12V fans query
 

Just as I was blowing out, with a 1KW Martindale, the crud of ages from an
amp and its fans.
Thought - these fans act as DC generators if blown forcefully. Presumably
you could damage, if driving negative volts into ps or fan contol circuit.
Next time I will jam something in the blades before zapping one with 1KW of
draught.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

12V fans query
 

On Tue, 25 Mar 2008 14:47:09 -0000, "N Cook"
wrote:

Just as I was blowing out, with a 1KW Martindale, the crud of ages from an
amp and its fans.
Thought - these fans act as DC generators if blown forcefully. Presumably
you could damage, if driving negative volts into ps or fan contol circuit.
Next time I will jam something in the blades before zapping one with 1KW of
draught.

All the fans I've seen were 'brushless' AC polyphase with protection
to the driver board (inside the fan) to prevent damage.

I suppose if you were reallyi creative you could turn one into an
alternator and generate (a small amount) of power with it... g

12V fans query
 

PeterD wrote:

On Tue, 25 Mar 2008 14:47:09 -0000, "N Cook"
wrote:


Just as I was blowing out, with a 1KW Martindale, the crud of ages from an
amp and its fans.
Thought - these fans act as DC generators if blown forcefully. Presumably
you could damage, if driving negative volts into ps or fan contol circuit.
Next time I will jam something in the blades before zapping one with 1KW of
draught.


All the fans I've seen were 'brushless' AC polyphase with protection
to the driver board (inside the fan) to prevent damage.

snip
Older DC Muffin Fans use DC permanent magnet motors, you can feel magnetic
detents as you rotate the blades.

Michael

12V fans query
 

"msg" wrote in message
...
PeterD wrote:

On Tue, 25 Mar 2008 14:47:09 -0000, "N Cook"
wrote:


Just as I was blowing out, with a 1KW Martindale, the crud of ages from
an
amp and its fans.
Thought - these fans act as DC generators if blown forcefully. Presumably
you could damage, if driving negative volts into ps or fan contol
circuit.
Next time I will jam something in the blades before zapping one with 1KW
of
draught.


All the fans I've seen were 'brushless' AC polyphase with protection
to the driver board (inside the fan) to prevent damage.

snip
Older DC Muffin Fans use DC permanent magnet motors, you can feel magnetic
detents as you rotate the blades.


They all have permanent magnet motors, but they're brushless. You can feel
detents on those too.

12V fans query
 

On 3ÔÂ25ÈÕ, ÏÂÎç10ʱ47·Ö, "N Cook" wrote:
Just as I was blowing out, with a 1KW Martindale, the crud of ages from an
amp and its fans.
Thought - these fans act as DC generators if blown forcefully. Presumably
you could damage, if driving negative volts into ps or fan contol circuit.
Next time I will jam something in the blades before zapping one with 1KW of
draught.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://home..graffiti.net/diverse:graffiti.net/



Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com

12V fans query
 

Meat Plow wrote in
:

On Tue, 25 Mar 2008 14:47:09 +0000, N Cook wrote:

Just as I was blowing out, with a 1KW Martindale, the crud of ages from
an amp and its fans.
Thought - these fans act as DC generators if blown forcefully.
Presumably you could damage, if driving negative volts into ps or fan
contol circuit. Next time I will jam something in the blades before
zapping one with 1KW of draught.

I've never given it a second thought. Nor have I ever damaged anything
by it. As a young lad I loved to turn my bicycle upside down and turn
the garden hose on the pedals and wheels and watch them spin.

I was having problems with my car. Was in a small town garage watching
while the guy removed the noisy wheel bearing from my front wheel. He
washed it a couple of swishes in solvent and grabbed the pressurized air
hose. As he started to blow the solvent out, the bearing started to spin.
It sounded like a warning siren.

Within a few seconds, it went 'BANG' and roller bearings ricochet around
the garage like bullets.

He yelled and started to nurse a sore hand.
His boss came out and explained to him why he should never do that.
(I think he had already learned the lesson.)

Well, I needed new wheel bearings, anyway.




--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

12V fans query
 

I used to turn my bicycle upside down and spin the devil out of the rear
wheel and then slam on the brake.I own a 1961 made in Germany moped with
sixteen original miles on it, it has bicycle pedals on it.
You can rig up an old computer hard drive motor if you want to make your
own wind speed aeronometer.I saw how to do it on the internet.
cuhulin

12V fans query
 

On Tue, 25 Mar 2008 11:04:22 -0400, PeterD put
finger to keyboard and composed:

On Tue, 25 Mar 2008 14:47:09 -0000, "N Cook"
wrote:

Just as I was blowing out, with a 1KW Martindale, the crud of ages from an
amp and its fans.
Thought - these fans act as DC generators if blown forcefully. Presumably
you could damage, if driving negative volts into ps or fan contol circuit.
Next time I will jam something in the blades before zapping one with 1KW of
draught.

All the fans I've seen were 'brushless' AC polyphase with protection
to the driver board (inside the fan) to prevent damage.

I suppose if you were reallyi creative you could turn one into an
alternator and generate (a small amount) of power with it... g

Brushless DC fan motors use integrated Hall effect sensors/ICs for
electronic commutation.

See these datasheets for examples:
http://www.anpec.com.tw/products/dow.../APX9141a7.pdf
http://www.anpec.com.tw/products/dow.../APX9140a8.pdf

These ICs have integral reverse voltage protection, as you have said.

Here is a more elaborate example:
http://web.archive.org/web/200605151...01/02/FIG2.JPG

I'm wondering how the EMF produced by the motor windings can generate
a current that passes through the switching elements, either in the
form of discrete transistors or internal to the commutator IC. I
suppose that in the latter example the current could flow through the
diodes.

As an experiment, I suppose you could attach two fan rotors
back-to-back with a suitable spacer (eg velco?) and use one fan to
drive the other.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

12V fans query
 

Meat Plow wrote:

On Tue, 25 Mar 2008 19:34:24 +0000, bz wrote:

Meat Plow wrote in
:

On Tue, 25 Mar 2008 14:47:09 +0000, N Cook wrote:

Just as I was blowing out, with a 1KW Martindale, the crud of ages from
an amp and its fans.
Thought - these fans act as DC generators if blown forcefully.
Presumably you could damage, if driving negative volts into ps or fan
contol circuit. Next time I will jam something in the blades before
zapping one with 1KW of draught.

I've never given it a second thought. Nor have I ever damaged anything
by it. As a young lad I loved to turn my bicycle upside down and turn
the garden hose on the pedals and wheels and watch them spin.

I was having problems with my car. Was in a small town garage watching
while the guy removed the noisy wheel bearing from my front wheel. He
washed it a couple of swishes in solvent and grabbed the pressurized air
hose. As he started to blow the solvent out, the bearing started to spin.
It sounded like a warning siren.

Within a few seconds, it went 'BANG' and roller bearings ricochet around
the garage like bullets.

He yelled and started to nurse a sore hand. His boss came out and
explained to him why he should never do that. (I think he had already
learned the lesson.)

Well, I needed new wheel bearings, anyway.

LOL great story.

I blew the rear end out of my 70 Dodge Charger R/T at a drag strip when I
was kid. A couple of the bolts that hold the ring gear to the carrier blew
right through the cover. Luckily nobody was standing behind me.


An Army buddy and I decided to head to Florida on a long weekend. We
got about 50 miles from Ft. Rucker when he threw a connecting rod, and
sent the piston through the oil pan. I found the piston about 150 feet
away with part of the sheared wrist pin and broken rod bolted to one
side. I took it back to the barracks and cleaned it up, and removed the
piece of the connecting rod. If you were careful, you could balance it
on the desk, on the one good surface. The next day we had some smart
ass sergeant along with the captain for Monday morning inspection. The
Sergeant grabbed it up and started yelling, demanding to know what it
was, and why it was on my desk. The captain had a big grin on his face,
so I smiled and told the jerk "It's a hemorrhoid extractor, would you
like me to demonstrate it on you?" He stormed out of the room, while
the Captain struggled to keep from laughing at him. :)


--
aioe.org is home to cowards and terrorists

Add this line to your news proxy nfilter.dat file
* drop Path:*aioe.org!not-for-mail to drop all aioe.org traffic.

http://improve-usenet.org/index.html

12V fans query
 

On Wed, 26 Mar 2008 06:41:05 +1100, Franc Zabkar
wrote:

On Tue, 25 Mar 2008 11:04:22 -0400, PeterD put
finger to keyboard and composed:

On Tue, 25 Mar 2008 14:47:09 -0000, "N Cook"
wrote:

Just as I was blowing out, with a 1KW Martindale, the crud of ages from an
amp and its fans.
Thought - these fans act as DC generators if blown forcefully. Presumably
you could damage, if driving negative volts into ps or fan contol circuit.
Next time I will jam something in the blades before zapping one with 1KW of
draught.

All the fans I've seen were 'brushless' AC polyphase with protection
to the driver board (inside the fan) to prevent damage.

I suppose if you were reallyi creative you could turn one into an
alternator and generate (a small amount) of power with it... g

Brushless DC fan motors use integrated Hall effect sensors/ICs for
electronic commutation.

See these datasheets for examples:
http://www.anpec.com.tw/products/dow.../APX9141a7.pdf
http://www.anpec.com.tw/products/dow.../APX9140a8.pdf

These ICs have integral reverse voltage protection, as you have said.

Here is a more elaborate example:
http://web.archive.org/web/200605151...01/02/FIG2.JPG

I'm wondering how the EMF produced by the motor windings can generate
a current that passes through the switching elements, either in the
form of discrete transistors or internal to the commutator IC. I
suppose that in the latter example the current could flow through the
diodes.


I wasn't clear, I was thinking rip out the electronics in there now
and add rectifiers...

As an experiment, I suppose you could attach two fan rotors
back-to-back with a suitable spacer (eg velco?) and use one fan to
drive the other.

- Franc Zabkar

12V fans query
 

I wasn't clear, I was thinking rip out the electronics in there now
and add rectifiers...



It works. A hard drive spindle motor also makes a decent miniature 3 phase
AC generator. You can even wire one up to another similar motor and it will
run, just like a regular 3 phase motor.

12V fans query
 

When anybody ask me about what something is for, I tell them it's a
windshield wiper for a billygoat's a..

You should never spin a dry bearing.One dry spin can ruin that bearing,
and often does.
cuhulin

12V fans query
 

Indeed this is true for modern versions, but DC Muffin fans from the 1960s
had brushes (electronic comutation would have been large and of
prohibitive
expense).



They had DC muffin fans in the 60s? I don't recall ever seeing one, what
were they used in? I've seen AC muffin fans powered by shaded pole motors,
and a few DC fans that were just a fan blade stuck on the end of a little DC
motor, but I've never come across one I'd call a muffin fan.

12V fans query
 

James Sweet wrote:

"msg" wrote in message
...

PeterD wrote:


On Tue, 25 Mar 2008 14:47:09 -0000, "N Cook"
wrote:



Just as I was blowing out, with a 1KW Martindale, the crud of ages from
an
amp and its fans.
Thought - these fans act as DC generators if blown forcefully. Presumably
you could damage, if driving negative volts into ps or fan contol
circuit.
Next time I will jam something in the blades before zapping one with 1KW
of
draught.


All the fans I've seen were 'brushless' AC polyphase with protection
to the driver board (inside the fan) to prevent damage.

snip
Older DC Muffin Fans use DC permanent magnet motors, you can feel magnetic
detents as you rotate the blades.



They all have permanent magnet motors, but they're brushless. You can feel
detents on those too.



Indeed this is true for modern versions, but DC Muffin fans from the 1960s
had brushes (electronic comutation would have been large and of prohibitive
expense).

Michael

12V fans query
 

msg wrote in
:

James Sweet wrote:

Indeed this is true for modern versions, but DC Muffin fans from the
1960s had brushes (electronic comutation would have been large and of
prohibitive
expense).




They had DC muffin fans in the 60s? I don't recall ever seeing one,
what were they used in? I've seen AC muffin fans powered by shaded
pole motors, and a few DC fans that were just a fan blade stuck on
the end of a little DC motor, but I've never come across one I'd call
a muffin fan.



I knew you'd ask ;) My recollections are from govt. contract gear
that used 24 or 28 VDC fans. These may not have been "Muffin" brand
fans but I am unable to inspect one any more as the gear is long gone.
Anyone else with these recollections?

One remarkable fan that I wish I still had was the 400 Hz "Minicube"
blower; about one inch on a side, it could easily levitate or blow
itself off of the bench under power. These were used on F111A
avionics boards (and no doubt other platforms as well)

Michael


I salvaged and ratholed some 12V fans from PC power supplies,and after
Hurricane Charlie knocked out power,I used two of them with a 12V/20 A-H
SLA battery to give me some quiet air circulation at night so I could sleep
in the 90+ deg temps. It was just enough to make me comfortable.
I also had a 8-AA cell 12v fluorescent lamp that I made an ext.power cable
to connect to a 12v SLA or car battery for lighting.

I was without power for 7 days.

--
Jim Yanik
jyanik
at
kua.net

12V fans query
 

James Sweet wrote:

Indeed this is true for modern versions, but DC Muffin fans from the 1960s
had brushes (electronic comutation would have been large and of
prohibitive
expense).




They had DC muffin fans in the 60s? I don't recall ever seeing one, what
were they used in? I've seen AC muffin fans powered by shaded pole motors,
and a few DC fans that were just a fan blade stuck on the end of a little DC
motor, but I've never come across one I'd call a muffin fan.



I knew you'd ask ;) My recollections are from govt. contract gear that used
24 or 28 VDC fans. These may not have been "Muffin" brand fans but I am unable
to inspect one any more as the gear is long gone. Anyone else with these
recollections?

One remarkable fan that I wish I still had was the 400 Hz "Minicube" blower;
about one inch on a side, it could easily levitate or blow itself off of
the bench under power. These were used on F111A avionics boards (and no
doubt other platforms as well)

Michael

12V fans query
 

msg wrote:

James Sweet wrote:

Indeed this is true for modern versions, but DC Muffin fans from the 1960s
had brushes (electronic comutation would have been large and of
prohibitive
expense).




They had DC muffin fans in the 60s? I don't recall ever seeing one, what
were they used in? I've seen AC muffin fans powered by shaded pole motors,
and a few DC fans that were just a fan blade stuck on the end of a little DC
motor, but I've never come across one I'd call a muffin fan.



I knew you'd ask ;) My recollections are from govt. contract gear that used
24 or 28 VDC fans. These may not have been "Muffin" brand fans but I am unable
to inspect one any more as the gear is long gone. Anyone else with these
recollections?


I had one out of a military radio or test set that was 24 VDC. It was
about 1.5" square, and about 2.75" deep. It was a regular brush motor,
about the size of the early dust buster with a regular fan blade.


One remarkable fan that I wish I still had was the 400 Hz "Minicube" blower;
about one inch on a side, it could easily levitate or blow itself off of
the bench under power. These were used on F111A avionics boards (and no
doubt other platforms as well)


The GRC-106 used them, too. I had a handful of ones pulled for noisy
bearings at the CE plant where we built the 106.


--
aioe.org is home to cowards and terrorists

Add this line to your news proxy nfilter.dat file
* drop Path:*aioe.org!not-for-mail to drop all aioe.org traffic.

http://improve-usenet.org/index.html

12V fans query
 

Jim Yanik wrote:

snip
I salvaged and ratholed some 12V fans from PC power supplies,and after
Hurricane Charlie knocked out power,I used two of them with a 12V/20 A-H
SLA battery to give me some quiet air circulation at night so I could sleep
in the 90+ deg temps. It was just enough to make me comfortable.
I also had a 8-AA cell 12v fluorescent lamp that I made an ext.power cable
to connect to a 12v SLA or car battery for lighting.

When I lost power some many years ago, I got six 200 AH deep cycle 12V
marine batteries (factory cosmetic seconds) to power a Sola 2.5KVA UPS
which I wired into the breaker panel, first disconnecting the utility
service. To charge the batteries I mated a 10 HP Briggs horiz. shaft
engine to an old military DC generator set; it's duty cycle was governed
by the batteries' specific gravity. The power was cleaner than what
I normally had and the UPS was continuous duty rated ;)

Michael

12V fans query
 

Deep cycle batteries are not suppose to be drained more than half way
down.More than that shortens the life span of those batteries.
cuhulin

12V fans query
 

As an experiment with no load other than DVM , neg to neg, 12V dc , 0.2A fan
, 1 foot from the nozzle of a 1KW fan then 17volt output from the fan I
tried.. Must have contained segmented magnets.
Turnuing the fan the other way in the airstream still produced "positive"
voltage.
I didn't try it any closer.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

12V fans query
 

wrote in message
...
Deep cycle batteries are not suppose to be drained more than half way
down.More than that shortens the life span of those batteries.
cuhulin


That rather depends on the construction of the plates in the battery, which
determine whether or not it is a genuine deep cycle battery, which is good
to 20%, or a sponge plated hybrid which is labelled "deep cycle", but is
only good, as you say, to 50% if you want a long life. Genuine marine
quality deep cycle batteries, as Michael suggested he was using, should be
of the former variety. The latter tend to be general leisure batteries, as
far as I know.

Arfa

12V fans query
 

On 3ÔÂ25ÈÕ, ÏÂÎç10ʱ47·Ö, "N Cook" wrote:
Just as I was blowing out, with a 1KW Martindale, the crud of ages from an
amp and its fans.
Thought - these fans act as DC generators if blown forcefully. Presumably
you could damage, if driving negative volts into ps or fan contol circuit.
Next time I will jam something in the blades before zapping one with 1KW of
draught.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://home..graffiti.net/diverse:graffiti.net/



Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com

12V fans query
 

On 3ÔÂ25ÈÕ, ÏÂÎç10ʱ47·Ö, "N Cook" wrote:
Just as I was blowing out, with a 1KW Martindale, the crud of ages from an
amp and its fans.
Thought - these fans act as DC generators if blown forcefully. Presumably
you could damage, if driving negative volts into ps or fan contol circuit.
Next time I will jam something in the blades before zapping one with 1KW of
draught.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://home..graffiti.net/diverse:graffiti.net/



Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com