On 15/08/16 19:57, Tim+ wrote:
The Natural Philosopher wrote:
On 15/08/16 13:58, Fredxxx wrote:
but the significant thing about a DC motor is you apply DC to
it. What happens inside the box isn't helpful.

Well obviously from the comment above you DO NOT know what a brushless
motor is, because if you apply DC to it, it melts.

It needs a controller which is usually externnal to the motor.




Next you and harry will be saying that there is no such thing as an
electrically powered motor, they're all magnetic.

AS I keep saying, its a matter of what you call a motor.

Is this, for example, a DC or an AC motor?

http://www.hobbyking.com/hobbyking/s...ner_Motor.html


Or only 'part of' a motor?



Where does this fit in the scheme of things?

https://youtu.be/i7LOF1GZpdo

Tim

Think that's another unipolar


--
Outside of a dog, a book is a man's best friend. Inside of a dog it's
too dark to read.

Groucho Marx

On 15/08/2016 19:57, Tim+ wrote:
The Natural Philosopher wrote:
On 15/08/16 13:58, Fredxxx wrote:
but the significant thing about a DC motor is you apply DC to
it. What happens inside the box isn't helpful.

Well obviously from the comment above you DO NOT know what a brushless
motor is, because if you apply DC to it, it melts.

It needs a controller which is usually externnal to the motor.




Next you and harry will be saying that there is no such thing as an
electrically powered motor, they're all magnetic.

AS I keep saying, its a matter of what you call a motor.

Is this, for example, a DC or an AC motor?

http://www.hobbyking.com/hobbyking/s...ner_Motor.html


Or only 'part of' a motor?



Where does this fit in the scheme of things?

https://youtu.be/i7LOF1GZpdo

Its not a unipolar motor. It's commonly called a ball bearing motor
attributed to Stefan Marinov.

http://www.electricstuff.co.uk/bbmotor.html#article

It relies on the thermal expansion of the balls in a ball bearing.

On 15/08/2016 20:17, The Natural Philosopher wrote:
On 15/08/16 19:22, Fredxxx wrote:
On 15/08/2016 17:58, harry wrote:
On Monday, 15 August 2016 14:01:41 UTC+1, Dave Plowman (News) wrote:
In article ,
tony sayer wrote:
The current is reversed as it passes under a brush turning it into
AC.

No Harry .. thats switched reversed polarity DC...

Well, yes. AC is generally a sine wave. Be good to see how you achieve
that with a switch. Many inverters make a pretty poor job of
producing a
sine wave. ;-)

AC can be any wave form.

Ah, so we are now saying DC is a special case of AC.

No. the current and voltage have to reverse to be alternating.

I see your command of English is as poor as your understanding of motor
theory.

My motor theory is fine, thanks for your concern.

Your understanding is more worrying where you claim your DC motors
should not be supplied with DC.

Similarly if you don't know the difference between a unipolar motor and
a ball bearing motor then you really ought to stop here.

In article ,
Fredxxx wrote:
On 15/08/2016 17:58, harry wrote:
On Monday, 15 August 2016 14:01:41 UTC+1, Dave Plowman (News) wrote:
In article , tony sayer
wrote:
The current is reversed as it passes under a brush turning it into
AC.

No Harry .. thats switched reversed polarity DC...

Well, yes. AC is generally a sine wave. Be good to see how you
achieve that with a switch. Many inverters make a pretty poor job of
producing a sine wave. ;-)

AC can be any wave form.

Ah, so we are now saying DC is a special case of AC.

Love to see harry trying to send square wave AC over a distance. ;-)

--
*All those who believe in psychokinesis, raise my hand *

Dave Plowman London SW
To e-mail, change noise into sound.

On Monday, 15 August 2016 19:22:53 UTC+1, Fredxxx wrote:
On 15/08/2016 17:58, harry wrote:
On Monday, 15 August 2016 14:01:41 UTC+1, Dave Plowman (News) wrote:
In article ,
tony sayer wrote:
The current is reversed as it passes under a brush turning it into AC.

No Harry .. thats switched reversed polarity DC...

Well, yes. AC is generally a sine wave. Be good to see how you achieve
that with a switch. Many inverters make a pretty poor job of producing a
sine wave. ;-)

AC can be any wave form.

Ah, so we are now saying DC is a special case of AC.

Indeed it can be regarded thus.
The frequency in this case is zero.

On Monday, 15 August 2016 19:57:06 UTC+1, Tim+ wrote:
The Natural Philosopher wrote:
On 15/08/16 13:58, Fredxxx wrote:
but the significant thing about a DC motor is you apply DC to
it. What happens inside the box isn't helpful.

Well obviously from the comment above you DO NOT know what a brushless
motor is, because if you apply DC to it, it melts.

It needs a controller which is usually externnal to the motor.




Next you and harry will be saying that there is no such thing as an
electrically powered motor, they're all magnetic.

AS I keep saying, its a matter of what you call a motor.

Is this, for example, a DC or an AC motor?

http://www.hobbyking.com/hobbyking/s...ner_Motor.html


Or only 'part of' a motor?



Where does this fit in the scheme of things?

https://youtu.be/i7LOF1GZpdo


https://en.wikipedia.org/wiki/Lorent...-carrying_wire

On Tuesday, 16 August 2016 01:13:12 UTC+1, Dave Plowman (News) wrote:
In article ,
Fredxxx wrote:
On 15/08/2016 17:58, harry wrote:
On Monday, 15 August 2016 14:01:41 UTC+1, Dave Plowman (News) wrote:
In article , tony sayer
wrote:
The current is reversed as it passes under a brush turning it into
AC.

No Harry .. thats switched reversed polarity DC...

Well, yes. AC is generally a sine wave. Be good to see how you
achieve that with a switch. Many inverters make a pretty poor job of
producing a sine wave. ;-)

AC can be any wave form.

Ah, so we are now saying DC is a special case of AC.

Love to see harry trying to send square wave AC over a distance. ;-)

What relevance has that to the discussion?

On 16/08/2016 07:09, harry wrote:
On Monday, 15 August 2016 19:57:06 UTC+1, Tim+ wrote:
The Natural Philosopher wrote:
On 15/08/16 13:58, Fredxxx wrote:
but the significant thing about a DC motor is you apply DC to
it. What happens inside the box isn't helpful.

Well obviously from the comment above you DO NOT know what a brushless
motor is, because if you apply DC to it, it melts.

It needs a controller which is usually externnal to the motor.




Next you and harry will be saying that there is no such thing as an
electrically powered motor, they're all magnetic.

AS I keep saying, its a matter of what you call a motor.

Is this, for example, a DC or an AC motor?

http://www.hobbyking.com/hobbyking/s...ner_Motor.html


Or only 'part of' a motor?



Where does this fit in the scheme of things?

https://youtu.be/i7LOF1GZpdo


https://en.wikipedia.org/wiki/Lorent...-carrying_wire

That is about as relevant to Tim+'s post as:
https://en.wikipedia.org/wiki/Gravity

On 16/08/2016 07:02, harry wrote:
On Monday, 15 August 2016 19:22:53 UTC+1, Fredxxx wrote:
On 15/08/2016 17:58, harry wrote:
On Monday, 15 August 2016 14:01:41 UTC+1, Dave Plowman (News) wrote:
In article ,
tony sayer wrote:
The current is reversed as it passes under a brush turning it into AC.

No Harry .. thats switched reversed polarity DC...

Well, yes. AC is generally a sine wave. Be good to see how you achieve
that with a switch. Many inverters make a pretty poor job of producing a
sine wave. ;-)

AC can be any wave form.

Ah, so we are now saying DC is a special case of AC.

Indeed it can be regarded thus.
The frequency in this case is zero.

Why would it be alternating current is it never changes polarity? It
does however indicate poor your poor understanding of basic electrics.

On 15/08/16 22:04, Fredxxx wrote:
On 15/08/2016 20:17, The Natural Philosopher wrote:
On 15/08/16 19:22, Fredxxx wrote:
On 15/08/2016 17:58, harry wrote:
On Monday, 15 August 2016 14:01:41 UTC+1, Dave Plowman (News) wrote:
In article ,
tony sayer wrote:
The current is reversed as it passes under a brush turning it into
AC.

No Harry .. thats switched reversed polarity DC...

Well, yes. AC is generally a sine wave. Be good to see how you achieve
that with a switch. Many inverters make a pretty poor job of
producing a
sine wave. ;-)

AC can be any wave form.

Ah, so we are now saying DC is a special case of AC.

No. the current and voltage have to reverse to be alternating.

I see your command of English is as poor as your understanding of motor
theory.

My motor theory is fine, thanks for your concern.

Your understanding is more worrying where you claim your DC motors
should not be supplied with DC.

And that, in a nutshell, betrays your lack of understanding.


I asked you to tell me whether the motor I linked to was DC or AC, or
what it was. You didn't respond.



Similarly if you don't know the difference between a unipolar motor and
a ball bearing motor then you really ought to stop here.

I didn't look very hard.

THere are 'perpetual motion' machines that use the 'pressure of
sunlight'. Too.


--
You can get much farther with a kind word and a gun than you can with a
kind word alone.

Al Capone

On 2016-08-12, David wrote:
On Thu, 11 Aug 2016 09:20:09 +0100, charles wrote:
Bicycle generators are all AC. Why would they need to be DC? Have you
never dismantled one?

I'd never thought about this. For lighting it doesn't matter at all
whether you generate AC or DC - it's only when you need to power
electronic equipment (eg USB charger) that you need some form of
rectification and smoothing.

Modern bike lighting uses LEDs, so rectification does matter.
(It's generally built into the light though, not the dynamo, so in
that sense it doesn't matter.)


Do modern dynamos that can power USB devices still generate AC, or do
they have the commutator rings wired to reverse the phase of the
negative cycles to give full-wave rectification? I suppose it's about
as easy to modify the generator as it is to add a couple of extra
diodes as part of all the other electronics needed to provide a
smoothed and regulated 5V for USB, together with a bit of storage in a
battery to cover times when you are going slower or when you stop at
lights.

I remember seeing some dynamo systems which had a battery container
attached to the frame. The advantage of batteries was that when you
stopped moving - eg at traffic lights, your cycle lights stayed on.

I had one on my bike in the early to mid sixties (which also had a hub
dynamo). Alloy tube which held about three U2 batteries (whatever they are
called now). The headlight had a 3 position switch underneath; on, off,
battery.

http://www.sheldonbrown.com/dynohubs.html has a illustration of that from
a 1952 Sturmey Archer catalogue, and also describes use of a bridge
rectifier to charge NiCds from a dynamo, the battery also acting as
regulation for the dynamo output.

These days standlights generally use supercapacitors built into the lights
though; it's only if you also want consistent output for something like a USB
charger that cache batteries are used.

In article ,
Alan Braggins wrote:
http://www.sheldonbrown.com/dynohubs.html has a illustration of that from
a 1952 Sturmey Archer catalogue, and also describes use of a bridge
rectifier to charge NiCds from a dynamo, the battery also acting as
regulation for the dynamo output.

Think that's wrong. The rectifier acted as a one way valve to prevent the
batteries discharging into the alternator when stopped. The batteries were
dry cells. The system would change over to battery when the alternator
output dropped - ie when stopped. Accompanied by a considerable drop in
light output. Fitted as standard on the Raleigh Superb. That heavy green
bike your school teacher rode.

I don't think Ni-Cads were around in 1952 - at least at a price a cyclist
would pay for.

--
*If you tell the truth, you don't have to remember anything.*

Dave Plowman London SW
To e-mail, change noise into sound.

On 2016-08-16, Dave Plowman (News) wrote:
Alan Braggins wrote:
http://www.sheldonbrown.com/dynohubs.html has a illustration of that from
a 1952 Sturmey Archer catalogue, and also describes use of a bridge
rectifier to charge NiCds from a dynamo, the battery also acting as
regulation for the dynamo output.

Think that's wrong. The rectifier acted as a one way valve to prevent the
batteries discharging into the alternator when stopped. The batteries were
dry cells.
[...]
I don't think Ni-Cads were around in 1952 - at least at a price a cyclist
would pay for.

The 1952 illustration is labelled "Dry battery unit". The use of "a 6 volt
(5 x 1.2v cell) nickel cadmium battery", also described on the same page,
is not from 1952.

In article ,
Alan Braggins wrote:
On 2016-08-16, Dave Plowman (News) wrote:
Alan Braggins wrote:
http://www.sheldonbrown.com/dynohubs.html has a illustration of that
from a 1952 Sturmey Archer catalogue, and also describes use of a
bridge rectifier to charge NiCds from a dynamo, the battery also
acting as regulation for the dynamo output.

Think that's wrong. The rectifier acted as a one way valve to prevent
the batteries discharging into the alternator when stopped. The
batteries were dry cells.
[...]
I don't think Ni-Cads were around in 1952 - at least at a price a
cyclist would pay for.

The 1952 illustration is labelled "Dry battery unit". The use of "a 6
volt (5 x 1.2v cell) nickel cadmium battery", also described on the same
page, is not from 1952.

Ah. Certainly when I was into bicycles in the 50s, the cells used were
primaries. And the auto switching (which used a rectifier) exclusive to
Raleigh. As I rather fancied the same idea on my Philips. But it is a long
long time ago.

--
*IF ONE SYNCHRONIZED SWIMMER DROWNS, DO THE REST DROWN TOO?

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Fredxxx
scribeth thus
On 15/08/2016 17:58, harry wrote:
On Monday, 15 August 2016 14:01:41 UTC+1, Dave Plowman (News) wrote:
In article ,
tony sayer wrote:
The current is reversed as it passes under a brush turning it into AC.

No Harry .. thats switched reversed polarity DC...

Well, yes. AC is generally a sine wave. Be good to see how you achieve
that with a switch. Many inverters make a pretty poor job of producing a
sine wave. ;-)

AC can be any wave form.

Ah, so we are now saying DC is a special case of AC.

Well it's still DC isn't it

--
Tony Sayer

In article , The Natural Philosopher
scribeth thus
On 15/08/16 13:50, tony sayer wrote:
thats switched reversed polarity DC...

...otherwise known as 'AC'...



Well it runs off DC..

Hence its a DC motor;!
--
Tony Sayer

On Tuesday, 16 August 2016 08:02:32 UTC+1, Fredxxx wrote:
On 16/08/2016 07:02, harry wrote:
On Monday, 15 August 2016 19:22:53 UTC+1, Fredxxx wrote:
On 15/08/2016 17:58, harry wrote:
On Monday, 15 August 2016 14:01:41 UTC+1, Dave Plowman (News) wrote:
In article ,
tony sayer wrote:
The current is reversed as it passes under a brush turning it into AC.

No Harry .. thats switched reversed polarity DC...

Well, yes. AC is generally a sine wave. Be good to see how you achieve
that with a switch. Many inverters make a pretty poor job of producing a
sine wave. ;-)

AC can be any wave form.

Ah, so we are now saying DC is a special case of AC.

Indeed it can be regarded thus.
The frequency in this case is zero.

Why would it be alternating current is it never changes polarity? It
does however indicate poor your poor understanding of basic electrics.

It indicates your poor understanding of elementary maths.
I spent forty years working with electrical machinery.

On 16/08/2016 08:29, The Natural Philosopher wrote:
On 15/08/16 22:04, Fredxxx wrote:
On 15/08/2016 20:17, The Natural Philosopher wrote:
On 15/08/16 19:22, Fredxxx wrote:
On 15/08/2016 17:58, harry wrote:
On Monday, 15 August 2016 14:01:41 UTC+1, Dave Plowman (News) wrote:
In article ,
tony sayer wrote:
The current is reversed as it passes under a brush turning it into
AC.

No Harry .. thats switched reversed polarity DC...

Well, yes. AC is generally a sine wave. Be good to see how you
achieve
that with a switch. Many inverters make a pretty poor job of
producing a
sine wave. ;-)

AC can be any wave form.

Ah, so we are now saying DC is a special case of AC.

No. the current and voltage have to reverse to be alternating.

I see your command of English is as poor as your understanding of motor
theory.

My motor theory is fine, thanks for your concern.

Your understanding is more worrying where you claim your DC motors
should not be supplied with DC.

And that, in a nutshell, betrays your lack of understanding.


I asked you to tell me whether the motor I linked to was DC or AC, or
what it was. You didn't respond.

I don't see any link.

On 17/08/2016 08:18, harry wrote:
On Tuesday, 16 August 2016 08:02:32 UTC+1, Fredxxx wrote:
On 16/08/2016 07:02, harry wrote:
On Monday, 15 August 2016 19:22:53 UTC+1, Fredxxx wrote:
On 15/08/2016 17:58, harry wrote:
On Monday, 15 August 2016 14:01:41 UTC+1, Dave Plowman (News) wrote:
In article ,
tony sayer wrote:
The current is reversed as it passes under a brush turning it into AC.

No Harry .. thats switched reversed polarity DC...

Well, yes. AC is generally a sine wave. Be good to see how you achieve
that with a switch. Many inverters make a pretty poor job of producing a
sine wave. ;-)

AC can be any wave form.

Ah, so we are now saying DC is a special case of AC.

Indeed it can be regarded thus.
The frequency in this case is zero.

Why would it be alternating current is it never changes polarity? It
does however indicate poor your poor understanding of basic electrics.

It indicates your poor understanding of elementary maths.
I spent forty years working with electrical machinery.

Clearly you have forgotten all about your experiences.