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BushWhacker
Junior Member
Canada
332 Posts |
 Posted - 31/08/2007 : 00:09:21
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I have these great little fans that are powered by a brushless stepper motor. They are 12 VDC, draw 0.66 amps each, and are polarity protected. They have three wires coming out of each fan, a red+, a black-, and a blue/white Idunno? Any guesses?
For 7.9 watts they move a fair bit of air but actually make quite a bit of noise as well. I'm feeding two of them with a 9 volt wall wart but played around with a third fan and a multi voltage (universal?) wall wart and prefer the noise level when the fan runs on 4.5 volts. It will run on 3 volts but not 1.5 volts.
Keeping in mind the polarity protection, can I run these in series without hurting anything? Positive power lead+to+fan-+fan-to-negative power lead?
If so, would the fans be running at about 1/2 of the input voltage?
If so, and I added a third fan, would all three be running at about 1/3 input voltage?
I'm just thinking along the lines of running batteries in series and wondering if it works backwards as well. The polarity protection is another thing that I have not learned about.
TIA!
BW
Everything should be made as simple as possible, but not one bit simpler. - Albert Einstein
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spumanti
Starting Member
Denmark
4 Posts |
 Posted - 31/08/2007 : 13:53:57
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Hi BushWacker
The blue/white wire is probably for monitoring the RPM of the motor/fan. (in most computer fans there are 3 leeds; black(-), red(+) and blue(pulse)).
My guess is that it is the same thing here.
Regarding running the motors in series:
In theory it should not be a problem as long as the 2 or 3 motors are identical. if they are not identical, the voltage drop through each motor would not be equal, and as a result, one motor could be running full speed, and the other be stopped (acting as a piece of wire).
As you mentioned about the batteries. you would not run batteries in series if they were not equal size, as one battery would be run down before the others. Same thing here. 
correct me if i'm wrong, anyone 
--
there's no place like 127.0.0.1
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BushWhacker
Junior Member
Canada
332 Posts |
Posted - 01/09/2007 : 03:04:27
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Thanks Spumanti,
I'll give it a go as there was no corrections to your post. All three fans have the same specs, just different manufacturer stickers. They look identical and are probably made in the same factory, just "branded" differently. I'll also let you know the results on this string.
Cheers!
BW
Everything should be made as simple as possible, but not one bit simpler. - Albert Einstein |
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Electricity question (wiring)
