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Old 11th May 2011, 08:06 PM   #21
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Quote:
Measure the same wire i did for the volage feeding the controller?
yes

Where is the connection to power the PWM board? How are you powering the PWM circuit?
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Old 11th May 2011, 08:17 PM   #22
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Quote:
Originally Posted by sofaspud View Post
yes

Where is the connection to power the PWM board? How are you powering the PWM circuit?
Click the image to open in full size.

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Specs for the unit are

Quote:
1. Input 12VDC - 40VDC, output to motor is 12VDC - 40VDC corresponding.
2. Maximum current 10A.
3. Output frequency 25Khz.
4. Duty cycle adjustment range: 0%-100
I have 12V off the ATX PC PSU via a Molex and cable rated 12v 10A

2) Control knob all the way to the minimum 12.02v

(3) Control knob all the way to maximum 11.38v

When turning to max it dips to 11.26v these rises to the above

A100K Verable Resistor - It came with the kit is the speed control
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Old 11th May 2011, 08:35 PM   #23
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You can see that it drops below the spec'd 12v minimum input.
I can't be 100% sure that is the cause of the problem. It's not good in any case.
I don't know what else to tell you.
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Old 11th May 2011, 08:40 PM   #24
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Just a thought. I think the problem is it's PWM and really needs to be linear, so maybe a PWM to linear is needed
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Old 11th May 2011, 08:56 PM   #25
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I don't know what else to tell you.
The way I see it, it makes little sense here to generate significant heat to implement a working cooling project. Keep the fans and linear circuit separate by some distance.
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Old 11th May 2011, 11:07 PM   #26
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Runs @ 7V but not @ 7V PWM equivalent?

Try a BIG capacitor across the output. 10,000 uF, 16V working.

It's pretty fast switching, so if you can find a choke from a SMPS (this'll be a toroid wound with THICK wire) try that in series too. Not the common mode one (bifilar wound, a pair of wires), although you can just use one winding, or rewind it.

There's no guarantee this will fix it, so any large cap, or smaller ones in parallel, with >12V working you can scrounge from something broken.

w
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Old 16th May 2011, 02:14 PM   #27
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Originally Posted by wakibaki View Post
Runs @ 7V but not @ 7V PWM equivalent?

Try a BIG capacitor across the output. 10,000 uF, 16V working.

It's pretty fast switching, so if you can find a choke from a SMPS (this'll be a toroid wound with THICK wire) try that in series too. Not the common mode one (bifilar wound, a pair of wires), although you can just use one winding, or rewind it.

There's no guarantee this will fix it, so any large cap, or smaller ones in parallel, with >12V working you can scrounge from something broken.

w
Sorry thats flown over my head a bit
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