On Wed, 18 Jan 2012 06:43:25 GMT, (Nico Coesel)
wrote:

John Larkin wrote:

On Tue, 17 Jan 2012 11:27:31 -0700, Jim Thompson
wrote:

On Tue, 17 Jan 2012 10:18:10 -0800, John Larkin
wrote:

[snip]

A uP would be good for sophisticated algorithms, like minimizing the
subjective effects of alternator drag.

John


So NOW it has drag?

...Jim Thompson

Conservation of Energy. Since a leisurely pedal down to the pub might
take, say, 20 watts of leg power, a few watts of charger kicking on
and off might be noticable and annoying. People already complain about
hub generator vibration. A commercial product would get bad reviews if
it annoyed the rider with erratic loading, so a $1 ARM with ADCs and
PWMs and algorithms would be appropriate to control it smoothly. But

Using a controller makes a lot of sense. I'm thinking about a PFC
scheme (about 25V into a big cap) and a forward converter-ish output
to drive a big LED. IMHO a battery is a bad idea. Better use a big
capacitor.

It does make sense to ride the high end of the load curve, namely
rectify the alternator output to a high voltage and then switch down.
That's the opposite from the "nearly shorted/constant-current" place
they usually work. The switcher will have to work from, roughly, 10 to
100 volts input, maybe more. I'm thinking the downhill run from the
Rainbow Bridge to Lake Donner...

John

On Wed, 18 Jan 2012 06:52:16 -0800, John Larkin
wrote:

On Tue, 17 Jan 2012 20:41:39 -0000, "Ian Field"
wrote:


"John Larkin" wrote in message
. ..
On Tue, 17 Jan 2012 11:16:46 -0700, Jim Thompson
wrote:

On Tue, 17 Jan 2012 12:49:23 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
om...

Here you go...

http://analog-innovations.com/SED/Bi...ubSwitcher.pdf

[snip]

I've only followed some of this "discussion" since it's become largely a
****ing match, but I see some questionable aspects of this design. First,
I
would want to examine the characteristics of the dynamo, and that may
mean
looking at several different models. The following websites list several:

I used the Magdowski model, link posted by Marcel.

I've noted in several posts that I was suspicious of the accuracy of
that model.

I'll check out your links, out of curiosity... I won't be doing
anymore posts on this subject... there's no point :-(


http://sheldonbrown.com/harris/lighting/shimano.html
http://sheldonbrown.com/harris/light...her-x-fdd.html
http://www.sheldonbrown.com/harris/l...g/schmidt.html

http://www.bikequarterly.com/VBQgenerator.pdf (efficiency testing)
http://www.nscl.msu.edu/~daniel/regulator.html (a simple bike generator
charger/regulator)
http://www.peterwhitecycles.com/schmidt.asp (detailed discussion of these
German hubs)

And most modern bicycle lamps are now LED, so the standard 6V 3W hub
generator can now produce a lot more light at the same power, or the same
amount of light with power left over to charge a battery. So the
incandescent lamp model is already obsolete, unless you insist on dealing
with antiques.

Yep, Ian is certainly an antique :-)

I did point this out also, just change to LED, and you've "loosened
up" enough juice to charge an added battery.

Remember my post upon return from lunch at Ra, where I looked over a
modern bicycle parked there?


Nonetheless, there seem to be flaws in the design. Assume the full 6V at
3W,
for a current of 0.5A. Diode R7 should be a Schottky, which will reduce
the
power loss from about 0.5W to 0.2W. The one ohm resistance of the
inductor
kills another 0.5W. And the charging current of the battery is not really
controlled in any way, so any excess voltage will just be dumped into the
battery and the power of the lamp will depend on its state of charge, so
a
low battery will limit the voltage to the lamp and/or cause possibly
excessive charging current.

You didn't read my text? Diode D7 was just for illustration
purposes... I suggested it be replaced by an active switch. I also
suggested regulation via burst mode control via the RESETbar of the
555.


Much more efficient, and simpler, would be a center tapped Schottky
rectifier which feeds the lamp from the greater of the generator voltage
or
the battery voltage, and then a PIC could be added to charge the battery
using a buck regulator. The lamp should be an LED which entails having
its
own buck switching supply which is available for less than a buck to
drive a
3V white LED from 6V with at least 90% efficiency. The PIC can monitor
the
dynamo voltage and current, and adjust the load for maximum power, while
charging the battery according to optimum current or voltage.

Such a system should give an efficiency of at least 85%, whereas the one
proposed is immediately crippled by losing 1W out of the available 3W, so
the efficiency must be less than 67%.

Anyone care to actually discuss this?

Paul
www.pstech-inc.com

I guess I seriously wasted my time finding out if the scheme had
potential?

That *was* the intent.

John


AFAICT - JT's intention is to screw everyone up with deliberate
misinformation.


You give him too much credit. He actually thought that switcher
circuit was clever.

John
Nope. Certainly not clever... just the usual game, except I used a
555, so just functional. The question _was_ will a buck buy some more
current. Answer: yes.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

"josephkk" wrote in message
...
On Mon, 16 Jan 2012 21:38:26 -0000, "Ian Field"
wrote:


I'm thinking maximise the minimalist.


How many switches do you want? What do they do?

As few as I can get away with.

As much as I can coax them into.


OK, be that way.

John


Eh!


Ian, i think you are starting to see some new light.

Can you get an actual sample of the waveform coming out of your dynamo?
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

My workshop is dismantled for refurb, my test gear is packed away in tea
chests at the back of the garage and the bicycle with the AG hub is chained
up behind the shed with a few snapped spokes.

"Tom Del Rosso" wrote in message
...

Ian Field wrote:
"Tom Del Rosso" wrote in message
...

Jim Thompson wrote:
My lawyer calls that tortuous interference.

Tortious interference.

"Tortuous interference" is like in the scene in "The Princess
Bride" where the machine is attached to the hero's nipples.

He'd probably enjoy that.

Well so would I.


--

Reply in group, but if emailing add one more
zero, and remove the last word.


TMI!

"josephkk" wrote in message
...
On Tue, 17 Jan 2012 21:48:22 -0000, "Ian Field"
wrote:


"Nico Coesel" wrote in message
...
John Larkin wrote:

On Tue, 17 Jan 2012 12:49:23 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
m...

Here you go...

http://analog-innovations.com/SED/Bi...ubSwitcher.pdf

[snip]

Anyone care to actually discuss this?

Paul
www.pstech-inc.com


If led's are so efficient that a couple of watts is enough, there's no
need to multiply the alternator current. No switcher, no transformer.
A rechargable battery is a nice idea, to have lighting when you're
going slow or stopped. Simple linear electronics is probably all you
need.

The tail light of my 15 year old bicycle uses a supercap to store
energy. It has enough storage to keep the led on for about a minute
after stopping. Ofcourse the tail light doesn't need to be very
bright.

I'd like to replace the front lamp with a led lamp though.


I bet whatever 'dynamo' you have is better than my old Sturmey archer AG
hub
which would only shift 1.8W loaded by the specified bulbs.

Currently I use it to charge a 1.2Ah SLA battery which powers a pair of
current sensing flyback converters that feed to series chains of LEDs, my
design was published in Elektor a few years ago.

The subject of my post on SED that triggered this thread here by JT was a
request on whether better load matching an old SA 'dynamo' could squeeze
more power from it - the consencus seems to be yes.

My read on that is more of a maybe, let's try it.

The extra power going into the battery would be handy for occasional use of
a 3W star LED "main beam" for unlit sections of cycleway.

Nice recap on what you have and where you want to go. Some others lost
sight of that.

I've lost count how many times I've corrected JT that *I AM* using LEDs -
but he still persists in calling me an "antique" for using bulbs!

Ian Field wrote:
"Tom Del Rosso" wrote in message

Well so would I.


TMI!

If you saw the movie you wouldn't take that seriously. It was a pain
machine.


--

Reply in group, but if emailing add one more
zero, and remove the last word.

On Wed, 18 Jan 2012 08:13:38 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 06:52:16 -0800, John Larkin
wrote:

On Tue, 17 Jan 2012 20:41:39 -0000, "Ian Field"
wrote:


"John Larkin" wrote in message
...
On Tue, 17 Jan 2012 11:16:46 -0700, Jim Thompson
wrote:

On Tue, 17 Jan 2012 12:49:23 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
news:rl46h7l10f6046gqr4f93vtmci1cnrle8r@4ax. com...

Here you go...

http://analog-innovations.com/SED/Bi...ubSwitcher.pdf

[snip]

I've only followed some of this "discussion" since it's become largely a
****ing match, but I see some questionable aspects of this design. First,
I
would want to examine the characteristics of the dynamo, and that may
mean
looking at several different models. The following websites list several:

I used the Magdowski model, link posted by Marcel.

I've noted in several posts that I was suspicious of the accuracy of
that model.

I'll check out your links, out of curiosity... I won't be doing
anymore posts on this subject... there's no point :-(


http://sheldonbrown.com/harris/lighting/shimano.html
http://sheldonbrown.com/harris/light...her-x-fdd.html
http://www.sheldonbrown.com/harris/l...g/schmidt.html

http://www.bikequarterly.com/VBQgenerator.pdf (efficiency testing)
http://www.nscl.msu.edu/~daniel/regulator.html (a simple bike generator
charger/regulator)
http://www.peterwhitecycles.com/schmidt.asp (detailed discussion of these
German hubs)

And most modern bicycle lamps are now LED, so the standard 6V 3W hub
generator can now produce a lot more light at the same power, or the same
amount of light with power left over to charge a battery. So the
incandescent lamp model is already obsolete, unless you insist on dealing
with antiques.

Yep, Ian is certainly an antique :-)

I did point this out also, just change to LED, and you've "loosened
up" enough juice to charge an added battery.

Remember my post upon return from lunch at Ra, where I looked over a
modern bicycle parked there?


Nonetheless, there seem to be flaws in the design. Assume the full 6V at
3W,
for a current of 0.5A. Diode R7 should be a Schottky, which will reduce
the
power loss from about 0.5W to 0.2W. The one ohm resistance of the
inductor
kills another 0.5W. And the charging current of the battery is not really
controlled in any way, so any excess voltage will just be dumped into the
battery and the power of the lamp will depend on its state of charge, so
a
low battery will limit the voltage to the lamp and/or cause possibly
excessive charging current.

You didn't read my text? Diode D7 was just for illustration
purposes... I suggested it be replaced by an active switch. I also
suggested regulation via burst mode control via the RESETbar of the
555.


Much more efficient, and simpler, would be a center tapped Schottky
rectifier which feeds the lamp from the greater of the generator voltage
or
the battery voltage, and then a PIC could be added to charge the battery
using a buck regulator. The lamp should be an LED which entails having
its
own buck switching supply which is available for less than a buck to
drive a
3V white LED from 6V with at least 90% efficiency. The PIC can monitor
the
dynamo voltage and current, and adjust the load for maximum power, while
charging the battery according to optimum current or voltage.

Such a system should give an efficiency of at least 85%, whereas the one
proposed is immediately crippled by losing 1W out of the available 3W, so
the efficiency must be less than 67%.

Anyone care to actually discuss this?

Paul
www.pstech-inc.com

I guess I seriously wasted my time finding out if the scheme had
potential?

That *was* the intent.

John


AFAICT - JT's intention is to screw everyone up with deliberate
misinformation.


You give him too much credit. He actually thought that switcher
circuit was clever.

John
Nope. Certainly not clever... just the usual game, except I used a
555, so just functional. The question _was_ will a buck buy some more
current. Answer: yes.

...Jim Thompson


I told you that a fixed-duty-cycle buck switcher would do that,
stably, a week before you posted that silly and unreliable circuit.
You know, back when you were still "puzzled."

I can't imagine why you considered something that fundamental to be a
"question" , or had to simulate it to find out.

John

On Wed, 18 Jan 2012 08:32:37 -0800, John Larkin
wrote:

On Wed, 18 Jan 2012 08:13:38 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 06:52:16 -0800, John Larkin
wrote:

On Tue, 17 Jan 2012 20:41:39 -0000, "Ian Field"
wrote:


"John Larkin" wrote in message
m...
On Tue, 17 Jan 2012 11:16:46 -0700, Jim Thompson
wrote:

On Tue, 17 Jan 2012 12:49:23 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
news:rl46h7l10f6046gqr4f93vtmci1cnrle8r@4ax .com...

Here you go...

http://analog-innovations.com/SED/Bi...ubSwitcher.pdf

[snip]

I've only followed some of this "discussion" since it's become largely a
****ing match, but I see some questionable aspects of this design. First,
I
would want to examine the characteristics of the dynamo, and that may
mean
looking at several different models. The following websites list several:

I used the Magdowski model, link posted by Marcel.

I've noted in several posts that I was suspicious of the accuracy of
that model.

I'll check out your links, out of curiosity... I won't be doing
anymore posts on this subject... there's no point :-(


http://sheldonbrown.com/harris/lighting/shimano.html
http://sheldonbrown.com/harris/light...her-x-fdd.html
http://www.sheldonbrown.com/harris/l...g/schmidt.html

http://www.bikequarterly.com/VBQgenerator.pdf (efficiency testing)
http://www.nscl.msu.edu/~daniel/regulator.html (a simple bike generator
charger/regulator)
http://www.peterwhitecycles.com/schmidt.asp (detailed discussion of these
German hubs)

And most modern bicycle lamps are now LED, so the standard 6V 3W hub
generator can now produce a lot more light at the same power, or the same
amount of light with power left over to charge a battery. So the
incandescent lamp model is already obsolete, unless you insist on dealing
with antiques.

Yep, Ian is certainly an antique :-)

I did point this out also, just change to LED, and you've "loosened
up" enough juice to charge an added battery.

Remember my post upon return from lunch at Ra, where I looked over a
modern bicycle parked there?


Nonetheless, there seem to be flaws in the design. Assume the full 6V at
3W,
for a current of 0.5A. Diode R7 should be a Schottky, which will reduce
the
power loss from about 0.5W to 0.2W. The one ohm resistance of the
inductor
kills another 0.5W. And the charging current of the battery is not really
controlled in any way, so any excess voltage will just be dumped into the
battery and the power of the lamp will depend on its state of charge, so
a
low battery will limit the voltage to the lamp and/or cause possibly
excessive charging current.

You didn't read my text? Diode D7 was just for illustration
purposes... I suggested it be replaced by an active switch. I also
suggested regulation via burst mode control via the RESETbar of the
555.


Much more efficient, and simpler, would be a center tapped Schottky
rectifier which feeds the lamp from the greater of the generator voltage
or
the battery voltage, and then a PIC could be added to charge the battery
using a buck regulator. The lamp should be an LED which entails having
its
own buck switching supply which is available for less than a buck to
drive a
3V white LED from 6V with at least 90% efficiency. The PIC can monitor
the
dynamo voltage and current, and adjust the load for maximum power, while
charging the battery according to optimum current or voltage.

Such a system should give an efficiency of at least 85%, whereas the one
proposed is immediately crippled by losing 1W out of the available 3W, so
the efficiency must be less than 67%.

Anyone care to actually discuss this?

Paul
www.pstech-inc.com

I guess I seriously wasted my time finding out if the scheme had
potential?

That *was* the intent.

John


AFAICT - JT's intention is to screw everyone up with deliberate
misinformation.


You give him too much credit. He actually thought that switcher
circuit was clever.

John
Nope. Certainly not clever... just the usual game, except I used a
555, so just functional. The question _was_ will a buck buy some more
current. Answer: yes.

...Jim Thompson


I told you that a fixed-duty-cycle buck switcher would do that,
stably, a week before you posted that silly and unreliable circuit.
You know, back when you were still "puzzled."

I can't imagine why you considered something that fundamental to be a
"question" , or had to simulate it to find out.

John


John, Is there some reason you have this need to be such a hateful
****-headed *******?

I was the one who _first_ posted that it wouldn't start as a usual
buck, which start (unless having a soft-start feature) at 100%... it
couldn't get over that initial "hump"... remember the "cartoon" you
made such a fuss over?

My puzzlement had to do with the dynamo's behavior, not how a buck
switcher works. I was, after all, designing buck switchers for
GenRad's portable products, while you were still a kid.

Why don't you knock it off?

And you're still clueless about why the dynamo won't work into an
auto-transformer.

But you'll still come screaming back with "say something technical",
rather than showing that you, yourself, have a clue... which you
don't, which is why you always revert to insults rather than facts...
and block diagrams supporting your cluelessness ;-)

But you'll remain a shiftless, hateful, narcissistic, ****-headed
******* forever.

I await your next shiftless, hateful, narcissistic, ****-headed
*******ly insult :-)

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Wed, 18 Jan 2012 09:48:56 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 08:32:37 -0800, John Larkin
wrote:

On Wed, 18 Jan 2012 08:13:38 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 06:52:16 -0800, John Larkin
wrote:

On Tue, 17 Jan 2012 20:41:39 -0000, "Ian Field"
wrote:


"John Larkin" wrote in message
om...
On Tue, 17 Jan 2012 11:16:46 -0700, Jim Thompson
wrote:

On Tue, 17 Jan 2012 12:49:23 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
news:rl46h7l10f6046gqr4f93vtmci1cnrle8r@4a x.com...

Here you go...

http://analog-innovations.com/SED/Bi...ubSwitcher.pdf

[snip]

I've only followed some of this "discussion" since it's become largely a
****ing match, but I see some questionable aspects of this design. First,
I
would want to examine the characteristics of the dynamo, and that may
mean
looking at several different models. The following websites list several:

I used the Magdowski model, link posted by Marcel.

I've noted in several posts that I was suspicious of the accuracy of
that model.

I'll check out your links, out of curiosity... I won't be doing
anymore posts on this subject... there's no point :-(


http://sheldonbrown.com/harris/lighting/shimano.html
http://sheldonbrown.com/harris/light...her-x-fdd.html
http://www.sheldonbrown.com/harris/l...g/schmidt.html

http://www.bikequarterly.com/VBQgenerator.pdf (efficiency testing)
http://www.nscl.msu.edu/~daniel/regulator.html (a simple bike generator
charger/regulator)
http://www.peterwhitecycles.com/schmidt.asp (detailed discussion of these
German hubs)

And most modern bicycle lamps are now LED, so the standard 6V 3W hub
generator can now produce a lot more light at the same power, or the same
amount of light with power left over to charge a battery. So the
incandescent lamp model is already obsolete, unless you insist on dealing
with antiques.

Yep, Ian is certainly an antique :-)

I did point this out also, just change to LED, and you've "loosened
up" enough juice to charge an added battery.

Remember my post upon return from lunch at Ra, where I looked over a
modern bicycle parked there?


Nonetheless, there seem to be flaws in the design. Assume the full 6V at
3W,
for a current of 0.5A. Diode R7 should be a Schottky, which will reduce
the
power loss from about 0.5W to 0.2W. The one ohm resistance of the
inductor
kills another 0.5W. And the charging current of the battery is not really
controlled in any way, so any excess voltage will just be dumped into the
battery and the power of the lamp will depend on its state of charge, so
a
low battery will limit the voltage to the lamp and/or cause possibly
excessive charging current.

You didn't read my text? Diode D7 was just for illustration
purposes... I suggested it be replaced by an active switch. I also
suggested regulation via burst mode control via the RESETbar of the
555.


Much more efficient, and simpler, would be a center tapped Schottky
rectifier which feeds the lamp from the greater of the generator voltage
or
the battery voltage, and then a PIC could be added to charge the battery
using a buck regulator. The lamp should be an LED which entails having
its
own buck switching supply which is available for less than a buck to
drive a
3V white LED from 6V with at least 90% efficiency. The PIC can monitor
the
dynamo voltage and current, and adjust the load for maximum power, while
charging the battery according to optimum current or voltage.

Such a system should give an efficiency of at least 85%, whereas the one
proposed is immediately crippled by losing 1W out of the available 3W, so
the efficiency must be less than 67%.

Anyone care to actually discuss this?

Paul
www.pstech-inc.com

I guess I seriously wasted my time finding out if the scheme had
potential?

That *was* the intent.

John


AFAICT - JT's intention is to screw everyone up with deliberate
misinformation.


You give him too much credit. He actually thought that switcher
circuit was clever.

John
Nope. Certainly not clever... just the usual game, except I used a
555, so just functional. The question _was_ will a buck buy some more
current. Answer: yes.

...Jim Thompson


I told you that a fixed-duty-cycle buck switcher would do that,
stably, a week before you posted that silly and unreliable circuit.
You know, back when you were still "puzzled."

I can't imagine why you considered something that fundamental to be a
"question" , or had to simulate it to find out.

John


John, Is there some reason you have this need to be such a hateful
****-headed *******?

I was the one who _first_ posted that it wouldn't start as a usual
buck, which start (unless having a soft-start feature) at 100%... it
couldn't get over that initial "hump"... remember the "cartoon" you
made such a fuss over?

My puzzlement had to do with the dynamo's behavior, not how a buck
switcher works. I was, after all, designing buck switchers for
GenRad's portable products, while you were still a kid.

Why don't you knock it off?

And you're still clueless about why the dynamo won't work into an
auto-transformer.

Explain why. Say something technical.

John

On Wed, 18 Jan 2012 09:35:40 -0800, John Larkin
wrote:

On Wed, 18 Jan 2012 09:48:56 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 08:32:37 -0800, John Larkin
wrote:

On Wed, 18 Jan 2012 08:13:38 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 06:52:16 -0800, John Larkin
wrote:

On Tue, 17 Jan 2012 20:41:39 -0000, "Ian Field"
wrote:


"John Larkin" wrote in message
news:7pfbh7h42jdv9ka7rorscs5csb6af226ti@4ax. com...
On Tue, 17 Jan 2012 11:16:46 -0700, Jim Thompson
wrote:

On Tue, 17 Jan 2012 12:49:23 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
news:rl46h7l10f6046gqr4f93vtmci1cnrle8r@4 ax.com...

Here you go...

http://analog-innovations.com/SED/Bi...ubSwitcher.pdf

[snip]

I've only followed some of this "discussion" since it's become largely a
****ing match, but I see some questionable aspects of this design. First,
I
would want to examine the characteristics of the dynamo, and that may
mean
looking at several different models. The following websites list several:

I used the Magdowski model, link posted by Marcel.

I've noted in several posts that I was suspicious of the accuracy of
that model.

I'll check out your links, out of curiosity... I won't be doing
anymore posts on this subject... there's no point :-(


http://sheldonbrown.com/harris/lighting/shimano.html
http://sheldonbrown.com/harris/light...her-x-fdd.html
http://www.sheldonbrown.com/harris/l...g/schmidt.html

http://www.bikequarterly.com/VBQgenerator.pdf (efficiency testing)
http://www.nscl.msu.edu/~daniel/regulator.html (a simple bike generator
charger/regulator)
http://www.peterwhitecycles.com/schmidt.asp (detailed discussion of these
German hubs)

And most modern bicycle lamps are now LED, so the standard 6V 3W hub
generator can now produce a lot more light at the same power, or the same
amount of light with power left over to charge a battery. So the
incandescent lamp model is already obsolete, unless you insist on dealing
with antiques.

Yep, Ian is certainly an antique :-)

I did point this out also, just change to LED, and you've "loosened
up" enough juice to charge an added battery.

Remember my post upon return from lunch at Ra, where I looked over a
modern bicycle parked there?


Nonetheless, there seem to be flaws in the design. Assume the full 6V at
3W,
for a current of 0.5A. Diode R7 should be a Schottky, which will reduce
the
power loss from about 0.5W to 0.2W. The one ohm resistance of the
inductor
kills another 0.5W. And the charging current of the battery is not really
controlled in any way, so any excess voltage will just be dumped into the
battery and the power of the lamp will depend on its state of charge, so
a
low battery will limit the voltage to the lamp and/or cause possibly
excessive charging current.

You didn't read my text? Diode D7 was just for illustration
purposes... I suggested it be replaced by an active switch. I also
suggested regulation via burst mode control via the RESETbar of the
555.


Much more efficient, and simpler, would be a center tapped Schottky
rectifier which feeds the lamp from the greater of the generator voltage
or
the battery voltage, and then a PIC could be added to charge the battery
using a buck regulator. The lamp should be an LED which entails having
its
own buck switching supply which is available for less than a buck to
drive a
3V white LED from 6V with at least 90% efficiency. The PIC can monitor
the
dynamo voltage and current, and adjust the load for maximum power, while
charging the battery according to optimum current or voltage.

Such a system should give an efficiency of at least 85%, whereas the one
proposed is immediately crippled by losing 1W out of the available 3W, so
the efficiency must be less than 67%.

Anyone care to actually discuss this?

Paul
www.pstech-inc.com

I guess I seriously wasted my time finding out if the scheme had
potential?

That *was* the intent.

John


AFAICT - JT's intention is to screw everyone up with deliberate
misinformation.


You give him too much credit. He actually thought that switcher
circuit was clever.

John
Nope. Certainly not clever... just the usual game, except I used a
555, so just functional. The question _was_ will a buck buy some more
current. Answer: yes.

...Jim Thompson


I told you that a fixed-duty-cycle buck switcher would do that,
stably, a week before you posted that silly and unreliable circuit.
You know, back when you were still "puzzled."

I can't imagine why you considered something that fundamental to be a
"question" , or had to simulate it to find out.

John


John, Is there some reason you have this need to be such a hateful
****-headed *******?

I was the one who _first_ posted that it wouldn't start as a usual
buck, which start (unless having a soft-start feature) at 100%... it
couldn't get over that initial "hump"... remember the "cartoon" you
made such a fuss over?

My puzzlement had to do with the dynamo's behavior, not how a buck
switcher works. I was, after all, designing buck switchers for
GenRad's portable products, while you were still a kid.

Why don't you knock it off?

And you're still clueless about why the dynamo won't work into an
auto-transformer.

Explain why. Say something technical.

John



Bwahahahaha ha! Now resorting to selective quoting. Answer the
technical question! But you don't know. Worse you don't know HOW to
check it.

I await your next shiftless, hateful, narcissistic, ****-headed
*******ly insult :-)

But no one awaits YOUR technical answer... because you can't.

You've been proven to be an ignorant blowhard.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jim Thompson wrote:

And you're still clueless about why the dynamo won't work into an
auto-transformer.

I asked about that transformer. (Which is not an autotransformer is it? It
has 2 coils.)

But Larkin did ask you to critique his architecture, and I pointed out that
if you just did that we could move along. So why don't you both explain why
it's necessary, or won't work, instead of this "you first".

Unless you want to make it a private conversation in which case you should
do it via email.


--

Reply in group, but if emailing add one more
zero, and remove the last word.

Jim Thompson wrote:

And you're still clueless about why the dynamo won't work into an
auto-transformer.

Oh, and I'm curious about this dynamo vs alternator issue. Some people have
said these things generate AC. If none of us have tested one, maybe we
should assume the worst.

Is that the only reason you oppose the use of a transformer? You might have
said so with less fuss.

Assuming the worst, I'd think to use a full wave bridge and no transformer.


--

Reply in group, but if emailing add one more
zero, and remove the last word.

On Wed, 18 Jan 2012 11:23:50 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 09:35:40 -0800, John Larkin
wrote:

On Wed, 18 Jan 2012 09:48:56 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 08:32:37 -0800, John Larkin
wrote:

On Wed, 18 Jan 2012 08:13:38 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 06:52:16 -0800, John Larkin
wrote:

On Tue, 17 Jan 2012 20:41:39 -0000, "Ian Field"
wrote:


"John Larkin" wrote in message
news:7pfbh7h42jdv9ka7rorscs5csb6af226ti@4ax .com...
On Tue, 17 Jan 2012 11:16:46 -0700, Jim Thompson
wrote:

On Tue, 17 Jan 2012 12:49:23 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
news:rl46h7l10f6046gqr4f93vtmci1cnrle8r@ 4ax.com...

Here you go...

http://analog-innovations.com/SED/Bi...ubSwitcher.pdf

[snip]

I've only followed some of this "discussion" since it's become largely a
****ing match, but I see some questionable aspects of this design. First,
I
would want to examine the characteristics of the dynamo, and that may
mean
looking at several different models. The following websites list several:

I used the Magdowski model, link posted by Marcel.

I've noted in several posts that I was suspicious of the accuracy of
that model.

I'll check out your links, out of curiosity... I won't be doing
anymore posts on this subject... there's no point :-(


http://sheldonbrown.com/harris/lighting/shimano.html
http://sheldonbrown.com/harris/light...her-x-fdd.html
http://www.sheldonbrown.com/harris/l...g/schmidt.html

http://www.bikequarterly.com/VBQgenerator.pdf (efficiency testing)
http://www.nscl.msu.edu/~daniel/regulator.html (a simple bike generator
charger/regulator)
http://www.peterwhitecycles.com/schmidt.asp (detailed discussion of these
German hubs)

And most modern bicycle lamps are now LED, so the standard 6V 3W hub
generator can now produce a lot more light at the same power, or the same
amount of light with power left over to charge a battery. So the
incandescent lamp model is already obsolete, unless you insist on dealing
with antiques.

Yep, Ian is certainly an antique :-)

I did point this out also, just change to LED, and you've "loosened
up" enough juice to charge an added battery.

Remember my post upon return from lunch at Ra, where I looked over a
modern bicycle parked there?


Nonetheless, there seem to be flaws in the design. Assume the full 6V at
3W,
for a current of 0.5A. Diode R7 should be a Schottky, which will reduce
the
power loss from about 0.5W to 0.2W. The one ohm resistance of the
inductor
kills another 0.5W. And the charging current of the battery is not really
controlled in any way, so any excess voltage will just be dumped into the
battery and the power of the lamp will depend on its state of charge, so
a
low battery will limit the voltage to the lamp and/or cause possibly
excessive charging current.

You didn't read my text? Diode D7 was just for illustration
purposes... I suggested it be replaced by an active switch. I also
suggested regulation via burst mode control via the RESETbar of the
555.


Much more efficient, and simpler, would be a center tapped Schottky
rectifier which feeds the lamp from the greater of the generator voltage
or
the battery voltage, and then a PIC could be added to charge the battery
using a buck regulator. The lamp should be an LED which entails having
its
own buck switching supply which is available for less than a buck to
drive a
3V white LED from 6V with at least 90% efficiency. The PIC can monitor
the
dynamo voltage and current, and adjust the load for maximum power, while
charging the battery according to optimum current or voltage.

Such a system should give an efficiency of at least 85%, whereas the one
proposed is immediately crippled by losing 1W out of the available 3W, so
the efficiency must be less than 67%.

Anyone care to actually discuss this?

Paul
www.pstech-inc.com

I guess I seriously wasted my time finding out if the scheme had
potential?

That *was* the intent.

John


AFAICT - JT's intention is to screw everyone up with deliberate
misinformation.


You give him too much credit. He actually thought that switcher
circuit was clever.

John
Nope. Certainly not clever... just the usual game, except I used a
555, so just functional. The question _was_ will a buck buy some more
current. Answer: yes.

...Jim Thompson


I told you that a fixed-duty-cycle buck switcher would do that,
stably, a week before you posted that silly and unreliable circuit.
You know, back when you were still "puzzled."

I can't imagine why you considered something that fundamental to be a
"question" , or had to simulate it to find out.

John


John, Is there some reason you have this need to be such a hateful
****-headed *******?

I was the one who _first_ posted that it wouldn't start as a usual
buck, which start (unless having a soft-start feature) at 100%... it
couldn't get over that initial "hump"... remember the "cartoon" you
made such a fuss over?

My puzzlement had to do with the dynamo's behavior, not how a buck
switcher works. I was, after all, designing buck switchers for
GenRad's portable products, while you were still a kid.

Why don't you knock it off?

And you're still clueless about why the dynamo won't work into an
auto-transformer.

Explain why. Say something technical.

John



Bwahahahaha ha! Now resorting to selective quoting. Answer the
technical question! But you don't know. Worse you don't know HOW to
check it.

I await your next shiftless, hateful, narcissistic, ****-headed
*******ly insult :-)

But no one awaits YOUR technical answer... because you can't.

You've been proven to be an ignorant blowhard.

...Jim Thompson

Say why an autotransformer won't work.

John

On Wed, 18 Jan 2012 13:40:13 -0500, "Tom Del Rosso"
wrote:


Jim Thompson wrote:

And you're still clueless about why the dynamo won't work into an
auto-transformer.

I asked about that transformer. (Which is not an autotransformer is it? It
has 2 coils.)

It doesn't matter if it's a transformer or an autotransformer. The
point is that, at decent speeds, the alternator is a high voltage and
a high impedance, practically a current source for low-resistance
loads like lamps. A step-down transformer can boost the current into
the load by better matching impedances. So can a
rectifier-filter-buck switcher, done right.

A 2:1 step-down autotransformer might be convenient to get from
Digikey, since you could use some standard part with dual primaries or
a center-tapped secondary.

John

On Wed, 18 Jan 2012 13:40:13 -0500, "Tom Del Rosso"
wrote:


Jim Thompson wrote:

And you're still clueless about why the dynamo won't work into an
auto-transformer.

I asked about that transformer. (Which is not an autotransformer is it? It
has 2 coils.)

An autotransformer simply is a winding-use expression. Think of a
simple 1:1 transformer, but connect the winding in series (minding the
"dots" :-) I assumed "perfect", K=1, and manipulated only inductance.
Input is end-to-end, output is across only one winding.

IF (and that's a big IF in my mind) the Magdowski dynamo model is
correct, an auto-transformer buys you only something on the order of
20% output current improvement.


But Larkin did ask you to critique his architecture, and I pointed out that
if you just did that we could move along. So why don't you both explain why
it's necessary, or won't work, instead of this "you first".

He claims, I asserted not. He won't/can't prove me wrong. But he
will continue to be crude. (I don't care, it's sort of fun... wonder
when he'll mentally crack ;-)

Unless you want to make it a private conversation in which case you should
do it via email.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Wed, 18 Jan 2012 13:46:47 -0500, "Tom Del Rosso"
wrote:


Jim Thompson wrote:

And you're still clueless about why the dynamo won't work into an
auto-transformer.

Oh, and I'm curious about this dynamo vs alternator issue.

Sort of interchangeable terms, but dynamos typically have permanent
magnet "fields", while "alternator" usually means a field made up of a
winding.

Some people have
said these things generate AC.

Yes. In automotive and some bicycle uses, followed by rectifiers.

If none of us have tested one, maybe we
should assume the worst.

Depends on your definition of "worst" :-)


Is that the only reason you oppose the use of a transformer? You might have
said so with less fuss.

I don't oppose the use of a transformer. Originally I thought
Larkin's idea was a good idea... that's why I tested it... it would be
an all-around easier device to regulate... but it fails, and I said
so, and have been castigated for it.


Assuming the worst, I'd think to use a full wave bridge and no transformer.

Yep. Full-wave bridge, no transformer, chased by an off-the-shelf
LiIon 3V charger chip to easily get the battery management (rolling
your own would take too many chips... I did my first LiIon
charge-discharge controller for CalMicro so long ago, pre-CAD, that I
only have paper schematics :-), LED lighting... add input regulation
to avoid over-voltage into the charger chip... at 3V it should be
_really_ simple.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Wed, 18 Jan 2012 12:01:10 -0800, John Larkin
wrote:

On Wed, 18 Jan 2012 11:23:50 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 09:35:40 -0800, John Larkin
wrote:

On Wed, 18 Jan 2012 09:48:56 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 08:32:37 -0800, John Larkin
wrote:

On Wed, 18 Jan 2012 08:13:38 -0700, Jim Thompson
wrote:

On Wed, 18 Jan 2012 06:52:16 -0800, John Larkin
m wrote:

On Tue, 17 Jan 2012 20:41:39 -0000, "Ian Field"
wrote:


"John Larkin" wrote in message
news:7pfbh7h42jdv9ka7rorscs5csb6af226ti@4a x.com...
On Tue, 17 Jan 2012 11:16:46 -0700, Jim Thompson
wrote:

On Tue, 17 Jan 2012 12:49:23 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
news:rl46h7l10f6046gqr4f93vtmci1cnrle8r @4ax.com...

Here you go...

http://analog-innovations.com/SED/Bi...ubSwitcher.pdf

[snip]

I've only followed some of this "discussion" since it's become largely a
****ing match, but I see some questionable aspects of this design. First,
I
would want to examine the characteristics of the dynamo, and that may
mean
looking at several different models. The following websites list several:

I used the Magdowski model, link posted by Marcel.

I've noted in several posts that I was suspicious of the accuracy of
that model.

I'll check out your links, out of curiosity... I won't be doing
anymore posts on this subject... there's no point :-(


http://sheldonbrown.com/harris/lighting/shimano.html
http://sheldonbrown.com/harris/light...her-x-fdd.html
http://www.sheldonbrown.com/harris/l...g/schmidt.html

http://www.bikequarterly.com/VBQgenerator.pdf (efficiency testing)
http://www.nscl.msu.edu/~daniel/regulator.html (a simple bike generator
charger/regulator)
http://www.peterwhitecycles.com/schmidt.asp (detailed discussion of these
German hubs)

And most modern bicycle lamps are now LED, so the standard 6V 3W hub
generator can now produce a lot more light at the same power, or the same
amount of light with power left over to charge a battery. So the
incandescent lamp model is already obsolete, unless you insist on dealing
with antiques.

Yep, Ian is certainly an antique :-)

I did point this out also, just change to LED, and you've "loosened
up" enough juice to charge an added battery.

Remember my post upon return from lunch at Ra, where I looked over a
modern bicycle parked there?


Nonetheless, there seem to be flaws in the design. Assume the full 6V at
3W,
for a current of 0.5A. Diode R7 should be a Schottky, which will reduce
the
power loss from about 0.5W to 0.2W. The one ohm resistance of the
inductor
kills another 0.5W. And the charging current of the battery is not really
controlled in any way, so any excess voltage will just be dumped into the
battery and the power of the lamp will depend on its state of charge, so
a
low battery will limit the voltage to the lamp and/or cause possibly
excessive charging current.

You didn't read my text? Diode D7 was just for illustration
purposes... I suggested it be replaced by an active switch. I also
suggested regulation via burst mode control via the RESETbar of the
555.


Much more efficient, and simpler, would be a center tapped Schottky
rectifier which feeds the lamp from the greater of the generator voltage
or
the battery voltage, and then a PIC could be added to charge the battery
using a buck regulator. The lamp should be an LED which entails having
its
own buck switching supply which is available for less than a buck to
drive a
3V white LED from 6V with at least 90% efficiency. The PIC can monitor
the
dynamo voltage and current, and adjust the load for maximum power, while
charging the battery according to optimum current or voltage.

Such a system should give an efficiency of at least 85%, whereas the one
proposed is immediately crippled by losing 1W out of the available 3W, so
the efficiency must be less than 67%.

Anyone care to actually discuss this?

Paul
www.pstech-inc.com

I guess I seriously wasted my time finding out if the scheme had
potential?

That *was* the intent.

John


AFAICT - JT's intention is to screw everyone up with deliberate
misinformation.


You give him too much credit. He actually thought that switcher
circuit was clever.

John
Nope. Certainly not clever... just the usual game, except I used a
555, so just functional. The question _was_ will a buck buy some more
current. Answer: yes.

...Jim Thompson


I told you that a fixed-duty-cycle buck switcher would do that,
stably, a week before you posted that silly and unreliable circuit.
You know, back when you were still "puzzled."

I can't imagine why you considered something that fundamental to be a
"question" , or had to simulate it to find out.

John


John, Is there some reason you have this need to be such a hateful
****-headed *******?

I was the one who _first_ posted that it wouldn't start as a usual
buck, which start (unless having a soft-start feature) at 100%... it
couldn't get over that initial "hump"... remember the "cartoon" you
made such a fuss over?

My puzzlement had to do with the dynamo's behavior, not how a buck
switcher works. I was, after all, designing buck switchers for
GenRad's portable products, while you were still a kid.

Why don't you knock it off?

And you're still clueless about why the dynamo won't work into an
auto-transformer.

Explain why. Say something technical.

John



Bwahahahaha ha! Now resorting to selective quoting. Answer the
technical question! But you don't know. Worse you don't know HOW to
check it.

I await your next shiftless, hateful, narcissistic, ****-headed
*******ly insult :-)

But no one awaits YOUR technical answer... because you can't.

You've been proven to be an ignorant blowhard.

...Jim Thompson

Say why an autotransformer won't work.

John

Because I say so. Prove me wrong.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

"Tom Del Rosso" wrote in message ...

Oh, and I'm curious about this dynamo vs alternator issue. Some people
have said these things generate AC. If none of us have tested one,
maybe we should assume the worst.

Is that the only reason you oppose the use of a transformer? You might
have said so with less fuss.

Assuming the worst, I'd think to use a full wave bridge and no
transformer.

I, too, am unsure whether hub dynamos produce AC or DC. Larkin's design with
the transformer assumes AC, while Thompson's assumes DC. If his "model"
includes diodes, then their specifications become very important to overall
efficiency, since two diode drops may constitute 1/4 of the voltage. If the
hub dynamo is a true alternator, then AFAIK it would contain diodes (as in
an automotive alternator), and would very likely use three (or six) phase.
But according to the following, the output IS AC, and it must be single
phase if there are only two terminals:
http://www.nscl.msu.edu/~daniel/sreg.htm

Perhaps even greater efficiency may be obtained by using a voltage doubler
consisting of two Schottky diodes and two capacitors. If the dynamo outputs
6 VAC then the doubler should produce about 16 VDC. However, the performance
at low speeds would depend on the frequency of the AC and the size of the
capacitors. The autotransformer is also subject to low frequency limitation,
and in fact may present a heavy load when it saturates at low frequency,
although not if the AC output is proportional to speed.

I think it would be advantageous to design a hub with a three-phase
topology, as it may reduce or eliminate the "cogging" effect that was
discussed in one of the articles. Another topology that might be
investigated is a three phase induction motor, which requires no expensive
magnets and is very rugged. But it does require sophisticated electronics
and a pre-existing voltage source to produce the rotating field. Or it might
be possible to use a SEIG, which could be accomplished with a small PM
generator to power the electronics which can then run off of a small
capacitor during times of no movement.

Since we have broached the subject of wheel hub generators, it opens up the
discussion to hub motors, which may provide enough power to assist the
cyclist on uphill climbs and then harvest the energy of downhill coasting,
even providing some braking force.

http://www.gizmag.com/green-wheel-el...bicycle/11076/
http://www.goldenmotor.com/
http://www.bicycle-power.com/diykits.html

Because of my problems with knees hips, and back, I can't really use an
ordinary bicycle, but one of these may fit the bill. But I may also try a
dog-powered cart, or bike-jouring equipment:

http://www.youtube.com/watch?v=1gwsKBcIrtk
http://youtu.be/12ZlXquqU8g

My dog Muttley sure pulls hard enough!
http://www.youtube.com/watch?v=HfQR5hZfrlk
http://youtu.be/MNOLgALlZuY (he helped pull my mower up the hill)

Paul and Muttley
www.muttleydog.com

Jim Thompson wrote:
On Wed, 18 Jan 2012 12:01:10 -0800, John Larkin

Say why an autotransformer won't work.

Because I say so. Prove me wrong.

Surely you realize that the only way to prove it _will_ work is by building
it.


--

Reply in group, but if emailing add one more
zero, and remove the last word.

Jim Thompson wrote:

Depends on your definition of "worst" :-)

I mean it would be best to make it work with AC or DC.


I don't oppose the use of a transformer. Originally I thought
Larkin's idea was a good idea... that's why I tested it... it would be
an all-around easier device to regulate... but it fails, and I said
so, and have been castigated for it.

That must have been another thread. I didn't see why it fails.


--

Reply in group, but if emailing add one more
zero, and remove the last word.

On Wed, 18 Jan 2012 15:50:39 -0500, "Tom Del Rosso"
wrote:


Jim Thompson wrote:
[dork delete]

Say why an autotransformer won't work.

Because I say so. Prove me wrong.

Surely you realize that the only way to prove it _will_ work is by building
it.

Possibly. I've said over-and-over, I'm suspicious of the Magdowski
model. Simulation using the Magdowski model fails.

But we're pursuing a dead horse. Anyone with half-a-brain would go to
LED lighting. Everything off-the-shelf for LED bicycle lighting is 3V
powered. If you've got an old hub dynamo-based bicycle you're home
free... only problem is that Ian doesn't have half a brain (likewise
Larkin ;-)

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

"Jim Thompson" wrote in message
...

Because I say so. Prove me wrong.

Jim, I'm not getting into this stupid ****ing match. But, erm, shouldn't you
be working on your mid-January project, rather than trading verbal volleys
with John? And, uh, what about your offer of free consulting, which I took
you up on a month ago? I had hoped to get at least a "little" bit more than
I paid for. The design is basically done, and I'm in the process of testing
some of the subcircuits and getting bobbins and ferrite cores for the
transformers. And I realize that my project is much more than a few hours
work. But what I WOULD like is at least a simple critique of my design for
the high-isolation DC-DC converter, and perhaps your official blessing (or
not) based on your PE credentials. I want to have some assurance that there
will be no design-related problems in the future from the 480V 200A mains
power jumping into the control circuitry and creating a big mess.

And if your advice and critique are sufficiently professional and valuable,
I may be interested in additional consulting work for which I would pay a
reasonable amount. Can you at least generate a report based on the material
I provided?

Please?

Paul
www.pstech-inc.com
www.etiinc.com (customer for whom I am doing this PI-200 project)

On Wed, 18 Jan 2012 15:53:24 -0500, "Tom Del Rosso"
wrote:


Jim Thompson wrote:

Depends on your definition of "worst" :-)

I mean it would be best to make it work with AC or DC.


I don't oppose the use of a transformer. Originally I thought
Larkin's idea was a good idea... that's why I tested it... it would be
an all-around easier device to regulate... but it fails, and I said
so, and have been castigated for it.

That must have been another thread. I didn't see why it fails.

The "Position Sensing" thread was also hijacked. To see why it fails,
run the Magdowski dynamo model into an auto-transformer whose
rectified output has to be = 6V.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Wed, 18 Jan 2012 15:45:52 -0500, "P E Schoen"
wrote:

"Tom Del Rosso" wrote in message ...

Oh, and I'm curious about this dynamo vs alternator issue. Some people
have said these things generate AC. If none of us have tested one,
maybe we should assume the worst.

Is that the only reason you oppose the use of a transformer? You might
have said so with less fuss.

Assuming the worst, I'd think to use a full wave bridge and no
transformer.

I, too, am unsure whether hub dynamos produce AC or DC. Larkin's design with
the transformer assumes AC, while Thompson's assumes DC.

Dynamo outputs AC, DC is required to charge a battery.

If his "model"
includes diodes, then their specifications become very important to overall
efficiency, since two diode drops may constitute 1/4 of the voltage. If the
hub dynamo is a true alternator, then AFAIK it would contain diodes (as in
an automotive alternator), and would very likely use three (or six) phase.
But according to the following, the output IS AC, and it must be single
phase if there are only two terminals:
http://www.nscl.msu.edu/~daniel/sreg.htm

As I've already stated, the CONCEPT works, efficiency can be brought
up in several ways.


Perhaps even greater efficiency may be obtained by using a voltage doubler
consisting of two Schottky diodes and two capacitors. If the dynamo outputs
6 VAC then the doubler should produce about 16 VDC. However, the performance
at low speeds would depend on the frequency of the AC and the size of the
capacitors. The autotransformer is also subject to low frequency limitation,
and in fact may present a heavy load when it saturates at low frequency,
although not if the AC output is proportional to speed.

The limitation is the dynamo characteristics. I tried
auto-transformers up to 100H inductance.

Besides, the output, according to Larkin is a CURRENT... not quite,
but almost.

[snip]

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Wed, 18 Jan 2012 16:04:39 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
.. .

Because I say so. Prove me wrong.

Jim, I'm not getting into this stupid ****ing match. But, erm, shouldn't you
be working on your mid-January project,

Starts Monday. Right now I'm revamping my office layout to fit in
some more file cabinets and storage.

rather than trading verbal volleys
with John? And, uh, what about your offer of free consulting, which I took
you up on a month ago? I had hoped to get at least a "little" bit more than
I paid for.

I asked for a description of WHAT you were trying to do. Schematics
and PCB layout did me no good, so I helped others.

The design is basically done, and I'm in the process of testing
some of the subcircuits and getting bobbins and ferrite cores for the
transformers. And I realize that my project is much more than a few hours
work. But what I WOULD like is at least a simple critique of my design for
the high-isolation DC-DC converter, and perhaps your official blessing (or
not) based on your PE credentials. I want to have some assurance that there
will be no design-related problems in the future from the 480V 200A mains
power jumping into the control circuitry and creating a big mess.

And if your advice and critique are sufficiently professional and valuable,
I may be interested in additional consulting work for which I would pay a
reasonable amount. Can you at least generate a report based on the material
I provided?

Tell me WHAT your circuit is supposed to accomplish, and I'll give it
a quick shot.

I didn't know that anyone here cares what I think ;-)


Please?

Paul
www.pstech-inc.com
www.etiinc.com (customer for whom I am doing this PI-200 project)

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jim Thompson wrote:

Possibly. I've said over-and-over, I'm suspicious of the Magdowski
model. Simulation using the Magdowski model fails.

Fails, with every circuit?


But we're pursuing a dead horse. Anyone with half-a-brain would go to
LED lighting. Everything off-the-shelf for LED bicycle lighting is 3V
powered. If you've got an old hub dynamo-based bicycle you're home
free... only problem is that Ian doesn't have half a brain (likewise
Larkin ;-)

Ian said a couple of times he is using LEDs.

Quote:

The extra power going into the battery would be handy for occasional use of
a 3W star LED "main beam" for unlit sections of cycleway.


--

Reply in group, but if emailing add one more
zero, and remove the last word.

On Wed, 18 Jan 2012 16:19:21 -0500, "Tom Del Rosso"
wrote:


Jim Thompson wrote:

Possibly. I've said over-and-over, I'm suspicious of the Magdowski
model. Simulation using the Magdowski model fails.

Fails, with every circuit?


But we're pursuing a dead horse. Anyone with half-a-brain would go to
LED lighting. Everything off-the-shelf for LED bicycle lighting is 3V
powered. If you've got an old hub dynamo-based bicycle you're home
free... only problem is that Ian doesn't have half a brain (likewise
Larkin ;-)

Ian said a couple of times he is using LEDs.

Quote:

The extra power going into the battery would be handy for occasional use of
a 3W star LED "main beam" for unlit sections of cycleway.

Then why was he pushing charging his _6V_ SLA ??

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

"Tom Del Rosso" wrote in message
...

Jim Thompson wrote:

And you're still clueless about why the dynamo won't work into an
auto-transformer.

Oh, and I'm curious about this dynamo vs alternator issue. Some people
have said these things generate AC. If none of us have tested one, maybe
we should assume the worst.

In British cycling terminology, the term "dynamo" is incorrectly applied to
the lighting generator - a dynamo has brushes and generates DC while bicycle
generators would be more correctly described as alternators.

Alternators come in a couple of principle types - permanent magnet and field
coil excited type.

Permanent magnet alternators are usual on bicycles and some types of
older/smaller motorcycles, field winding alternators are usual on
newer/larger motorcycles and on cars.

Alternators produce AC - you can always be fed through a rectifier if you
need to charge a battery.

AFAIK the misuse of the term "dynamo" is largely confined to Britain - the
term "generator" is used more widely in connection with bicycles.

"Jim Thompson" wrote in message
...

I asked for a description of WHAT you were trying to do. Schematics
and PCB layout did me no good, so I helped others.

I had sent you a fairly complete project outline
ETI_Next_Gen_Test_Set_PI-200.doc with my initial contact email sent on
December 18. But that was rather comprehensive and included the entire
design, whereas I later condensed my requirements to just the high-isolation
DC-DC converter, which mostly involved the transformer design and the driver
to obtain about 6-9 VDC at 300 mA from a 12VDC supply. The schematics
included my design for that subcircuit, and I really just wanted your
opinion on how the board should be laid out to achieve the safety and
isolation of the 480 VAC mains.

My description of this portion of the design, from my email of January 6,
2012:

================================================== ==================
I think the most reasonable approach at this point is to have you design a
small, but important, component of the system. The document I sent you
described the unit and some of the components, and most of that has already
been designed. But I am now working on the SCR gate drive, which requires a
high isolation DC-DC converter. I am getting quotes on the transformer I
need for this, but perhaps you can help. Here is what I have sent to some
local transformer shops we have used:

I am designing a new SCR trigger board for a smaller test set (PI-200, for
which you recently provided a transformer quote), but may also be used for
the larger ones, and I will need a special transformer for a DC-DC converter
for the gate drives. I will supply a 12 V P-P square wave to the primary,
and the secondary will be a full wave bridge using Schottky rectifiers to
produce a nominal 8VDC at about 400mA. I was planning to use a switching
frequency of about 20-40 kHz, to keep the transformer size small. But I need
to have isolation and safety for use with nominal 480 VAC mains. The best
commercial DC-DC converters I could find are the:

http://www.powergatellc.com/traco-po...converter.html

They are rated 4000 VRMS isolation but for continuous duty only up to 300V.
I would like a transformer that is no larger than these units (about 1.5€�
x 1€� x 0.5€�), and I can supply the drive and output electronics. I am
designing the circuitry now and I plan to design the PC boards in about a
week, so I need at least the basic form factor that a custom transformer
would take.

I think a split bobbin design might be best, something like the Atech
ATS-075A. (See attached files). It has 3750 VRMS hypot but it€„¢s 600 ohms
impedance. I have one and it appears to have steel laminations. That is
probably OK for 20 kHz but maybe ferrite is better if I use 40 kHz.

The Triad CSE187L is also the right size, but the split bobbin is of unequal
size, since it is a current transformer with a single turn 30A primary.

I have also made a transformer using a ferrite toroid and about 30 turns of
#26 enamel wire. But I don€„¢t know if the coated core can be trusted for
480 VAC use.

However, perhaps I can just use some very well insulated wire (perhaps
Teflon) for the primary and secondary of a toroid (or other type). If the
insulation is rated to withstand 480-600 VAC continuous then that would be
another option.

I have also found some laminations from Thomas Skinner
http://www.thomas-skinner.com/index.html that are 0.75€�x1.00€� (EE-24-25)
of 4-14 mils thickness, and I found a good selection of bobbins from
http://www.cosmocorp.com/en/corp-overview.cfm.

That should be enough to get you started. I have the PCB laid out for the
Atech ATS-075, but I can easily modify the decal for another type. But I
would like to have the size be not much larger. Maximum is about 1€� square
and about 0.75€Â� high. Basically I have 12 VDC available and I€„¢d like to
get about 8 VDC at a minimum of 300 mADC for the gate drive of the larger
SCRs. But if that causes a size problem, I€„¢d be OK with about 5 VDC at 250
mA.

And a major consideration is the 480 VAC mains. I plan to use the 1.25A 600V
SMT fuses for the gate and cathode wires, as discussed in S.E.D. recently.

Littelfuse 04611.25ER, Newark 34C6800

================================================== ===========

I don't know what more you need. And I was using this as a test to see if
you could offer help for other things in the future. Oh, well. There are
others who may be able to help with other issues. Good luck on your
renovations and main project. And please don't continue this ongoing
argument with Larkin, or at least snip all the previous worthless chatter.
What was it you said about his wife that got him all riled up, anyway?

Paul

Jim Thompson wrote:

Then why was he pushing charging his _6V_ SLA ??

I don't know. The supply for the big LED lamp could be anything.


--

Reply in group, but if emailing add one more
zero, and remove the last word.

On Wed, 18 Jan 2012 16:43:18 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
.. .

I asked for a description of WHAT you were trying to do. Schematics
and PCB layout did me no good, so I helped others.

I had sent you a fairly complete project outline
ETI_Next_Gen_Test_Set_PI-200.doc with my initial contact email sent on
December 18. But that was rather comprehensive and included the entire
design, whereas I later condensed my requirements to just the high-isolation
DC-DC converter, which mostly involved the transformer design and the driver
to obtain about 6-9 VDC at 300 mA from a 12VDC supply.
[snip]

My specialty is circuit design, primarily chips, so I can't help on
transformers. I was specifically wondering what you were trying to
accomplish with the SCR... particularly wondering if there wasn't
possibly a better way to hold current thru the zero crossing.

Larkin? He made a snarky remark about MIT, and how his wife, while at
BU, waited tables and thought MIT types were geeks (of course we are
:-). I truthfully remarked that, at MIT frats across the river, they
had telescopes set up to watch the BU gals parading at their open
dormitory windows, showing off their wares. I also asked for the
names of the restaurants she supposedly waited at table. They drove
Larkin into one of his mentally defective states, and he's not let up
since. (And I think he made up the part about waiting tables... he
still hasn't provided any restaurant names.)

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On 1/18/2012 4:24 PM, Jim Thompson wrote:
On Wed, 18 Jan 2012 16:43:18 -0500, "P E
wrote:

"Jim Thompson" wrote in message
...

I asked for a description of WHAT you were trying to do. Schematics
and PCB layout did me no good, so I helped others.

I had sent you a fairly complete project outline
ETI_Next_Gen_Test_Set_PI-200.doc with my initial contact email sent on
December 18. But that was rather comprehensive and included the entire
design, whereas I later condensed my requirements to just the high-isolation
DC-DC converter, which mostly involved the transformer design and the driver
to obtain about 6-9 VDC at 300 mA from a 12VDC supply.
[snip]

My specialty is circuit design, primarily chips, so I can't help on
transformers. I was specifically wondering what you were trying to
accomplish with the SCR... particularly wondering if there wasn't
possibly a better way to hold current thru the zero crossing.

Larkin? He made a snarky remark about MIT, and how his wife, while at
BU, waited tables and thought MIT types were geeks (of course we are
:-). I truthfully remarked that, at MIT frats across the river, they
had telescopes set up to watch the BU gals parading at their open
dormitory windows, showing off their wares. I also asked for the
names of the restaurants she supposedly waited at table. They drove
Larkin into one of his mentally defective states, and he's not let up
since. (And I think he made up the part about waiting tables... he
still hasn't provided any restaurant names.)

...Jim Thompson

Jim, you know that JL can't resist replying to your post (above). Let it
go, and I feel fairly certain that you will be one-up with the group, if
that matters.

John S

"Jim Thompson" wrote in message
...

My specialty is circuit design, primarily chips, so I can't help on
transformers. I was specifically wondering what you were trying to
accomplish with the SCR... particularly wondering if there wasn't
possibly a better way to hold current thru the zero crossing.

That may best be reserved for another thread. But we have discovered that,
for highly inductive loads, applying a gate signal on the positive excursion
of the voltage waveform means that it will be removed at the point of peak
current, and relies on the SCR's current latching characteristic to maintain
conduction through the zero crossing. But there is a point where the current
drops below this level, and I surmise that the current still flowing will
create an inductive voltage "kick" which causes a distorted waveform at the
zero crossing. At this point, the opposite device's gate drive will have
already been ON for a quarter cycle, so the distortion appears only at the
end of the current waveform.

Sometimes this seems to cause erratic behavior and latch-up, where the SCR
may be turned back on, and sometimes this happens only on one SCR, which
causes a net DC component and correspondingly very high input current which
trips the mains protection instantly. On a 200 amp source this means the
fault current is at least 2000 amps, and probably much higher.

I don't know exactly why the continuous gate drive works to solve this
problem, and it may not do so completely, but it has been shown to be
effective and I don't know of any downside. I don't think maintaining 300 mA
on the gates does any damage. We've had SCRs in the field using this method
for at least ten years, and most failures seem to be due to an open gate
wire or customer abuse. We have dealt with the former by using the new SCR
trigger board which checks for gate continuity before triggering, and we
have reduced the latter by using a "programmable overload device", or POD,
which limits the duty cycle of operation.

Last I heard from you it seemed you were interested in this phenomenon. But
I didn't realize you had no experience with transformer construction and
high isolation DC-DC converter design. Now that I review your areas of
expertise I see that the closest relative is switching power supply design,
and they are typically only rated for common mains voltages up to 265 VAC.
It would be really helpful to find one that works on 480 VAC mains, but I
have searched in vain. However I recall seeing something recently that might
be suitable for this purpose.

Thanks,

Paul

On Wed, 18 Jan 2012 18:17:40 -0500, "P E Schoen"
wrote:

"Jim Thompson" wrote in message
.. .

My specialty is circuit design, primarily chips, so I can't help on
transformers. I was specifically wondering what you were trying to
accomplish with the SCR... particularly wondering if there wasn't
possibly a better way to hold current thru the zero crossing.

That may best be reserved for another thread. But we have discovered that,
for highly inductive loads, applying a gate signal on the positive excursion
of the voltage waveform means that it will be removed at the point of peak
current, and relies on the SCR's current latching characteristic to maintain
conduction through the zero crossing. But there is a point where the current
drops below this level, and I surmise that the current still flowing will
create an inductive voltage "kick" which causes a distorted waveform at the
zero crossing. At this point, the opposite device's gate drive will have
already been ON for a quarter cycle, so the distortion appears only at the
end of the current waveform.

Sometimes this seems to cause erratic behavior and latch-up, where the SCR
may be turned back on, and sometimes this happens only on one SCR, which
causes a net DC component and correspondingly very high input current which
trips the mains protection instantly. On a 200 amp source this means the
fault current is at least 2000 amps, and probably much higher.

I don't know exactly why the continuous gate drive works to solve this
problem, and it may not do so completely, but it has been shown to be
effective and I don't know of any downside. I don't think maintaining 300 mA
on the gates does any damage. We've had SCRs in the field using this method
for at least ten years, and most failures seem to be due to an open gate
wire or customer abuse. We have dealt with the former by using the new SCR
trigger board which checks for gate continuity before triggering, and we
have reduced the latter by using a "programmable overload device", or POD,
which limits the duty cycle of operation.

Last I heard from you it seemed you were interested in this phenomenon. But
I didn't realize you had no experience with transformer construction and
high isolation DC-DC converter design. Now that I review your areas of
expertise I see that the closest relative is switching power supply design,
and they are typically only rated for common mains voltages up to 265 VAC.
It would be really helpful to find one that works on 480 VAC mains, but I
have searched in vain. However I recall seeing something recently that might
be suitable for this purpose.

Thanks,

Paul

Yep. I did a lot of off-line stuff, but before PF correction became a
requirement.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Ian Field wrote:

"Tom Del Rosso" wrote in message
...

Jim Thompson wrote:

And you're still clueless about why the dynamo won't work into an
auto-transformer.

Oh, and I'm curious about this dynamo vs alternator issue. Some people
have said these things generate AC. If none of us have tested one, maybe
we should assume the worst.


In British cycling terminology, the term "dynamo" is incorrectly applied to
the lighting generator - a dynamo has brushes and generates DC while bicycle
generators would be more correctly described as alternators.

Alternators come in a couple of principle types - permanent magnet and field
coil excited type.

Permanent magnet alternators are usual on bicycles and some types of
older/smaller motorcycles, field winding alternators are usual on
newer/larger motorcycles and on cars.

And let us not forget that these non-pm alternators have not used
brushes for the field for years now. Nothing but bearings and the
unexpected mishap to take place now.


Alternators produce AC - you can always be fed through a rectifier if you
need to charge a battery.

AFAIK the misuse of the term "dynamo" is largely confined to Britain - the
term "generator" is used more widely in connection with bicycles.



Jamie

"Jamie" wrote in message ...

And let us not forget that these non-pm alternators have not used brushes
for the field for years now. Nothing but bearings and the unexpected
mishap to take place now.

According to one reference, some models of wheel hub generators had problems
with water entering the enclosure when the bike was moved from a warm garage
to the cold outdoors and ridden in the rain. The temperature differential
created a relative vacuum in the hub which sucked water in through the seals
which were not designed with that in mind. Newer models apparently corrected
the problem. But if water does enter the assembly it tends to corrode the
rotor and stator poles which have very small clearance and cause them to
bind.

Paul

On Wed, 18 Jan 2012 18:46:14 -0500, Jamie
t wrote:

[snip]

And let us not forget that these non-pm alternators have not used
brushes for the field for years now. Nothing but bearings and the
unexpected mishap to take place now.

[snip]

Huh? How does that work?

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jim Thompson wrote:

On Wed, 18 Jan 2012 18:46:14 -0500, Jamie
t wrote:

[snip]

And let us not forget that these non-pm alternators have not used
brushes for the field for years now. Nothing but bearings and the
unexpected mishap to take place now.


[snip]

Huh? How does that work?

...Jim Thompson

They have not been using brushes in alternators in cars for a long time
now. They may still use them in very large units however.

Since you never believe me on anything, maybe you can believe others.

He

http://www.pearen.ca/dunlite/BrushlessAlternators.pdf

Jamie

On Wed, 18 Jan 2012 20:48:13 -0500, Jamie
t wrote:

Jim Thompson wrote:

On Wed, 18 Jan 2012 18:46:14 -0500, Jamie
t wrote:

[snip]

And let us not forget that these non-pm alternators have not used
brushes for the field for years now. Nothing but bearings and the
unexpected mishap to take place now.


[snip]

Huh? How does that work?

...Jim Thompson

They have not been using brushes in alternators in cars for a long time
now. They may still use them in very large units however.

Since you never believe me on anything, maybe you can believe others.

He

http://www.pearen.ca/dunlite/BrushlessAlternators.pdf

Jamie


OK. I've not seen that in a passenger car. My Q45 has slip-rings.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jim Thompson wrote:

On Wed, 18 Jan 2012 20:48:13 -0500, Jamie
t wrote:


Jim Thompson wrote:


On Wed, 18 Jan 2012 18:46:14 -0500, Jamie
et wrote:

[snip]


And let us not forget that these non-pm alternators have not used
brushes for the field for years now. Nothing but bearings and the
unexpected mishap to take place now.


[snip]

Huh? How does that work?

...Jim Thompson

They have not been using brushes in alternators in cars for a long time
now. They may still use them in very large units however.

Since you never believe me on anything, maybe you can believe others.

He

http://www.pearen.ca/dunlite/BrushlessAlternators.pdf

Jamie



OK. I've not seen that in a passenger car. My Q45 has slip-rings.

...Jim Thompson

Talking about slip rings. We still operate many large AC motors (Eddy
current clutches) via slip rings.. They actually work much better for
constant tension control over today's preferred vector systems.

But, they are getting old like the rest of us and soon to see their
demise.

Jamie