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Brand new Motor speed controllers (PWM) getting real hot

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kal.a

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I purchased a CanaKit like the one in this link and I correctly wired it to a 12VDC and did not wire any load to it. As soon as I turn the power on it gets quite hot that it is almost melting. After the first time I tried a few more times but for a second or two just to measure the output at M- and M+ without load and got almost 0 volts. Any ideas what I'm doing wrong?
 
I think you may have to have a load connected, wire a motor up to it and try again.
Plus your multimeter may not be able to read the o/p, you really need a meter that will measure duty.
 
Did you fuse the input?

Did you contact tech support?
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Did you connect a fan?
Does it recommend a snubber?

I think the battery or power supply should be close to unit otherwise a low ESR cap may be necessary on unit.

Tech support is your best bet.
 
Last edited:
Thanks guys.
I'm using a 4 Amp transformer and a NTE53020 rectifier1000V,50 A and they're all right there with the controller. No more than a foot of wire.


No fan though one is available as an option
 
@kal.l that power source does not satisfy the requirements as given.

What caps are used and what voltage? ripple? You better use a 12V battery if it is not damaged already.
 
Hi Tony,

Why do you say it doesn't satisfy power requirement? 12VDC and 4 amp transformer with no load. I am not drawing anything from it yet. Please explain in as simple a form as possible as all this is new to me.

Thanks
Kal
 
This unit shows no power conditioning and PWM switch mode drivers depend on a good DC voltage sources.

A transformer and bridge alone is an inductive source a switched load creates large voltage spikes which in turn can create false triggering.

If you are using 50 Hz then the bridge would output 100Hz.
Typically 10% ripple is allowed on input but may be excessive for this product.
If you are driving a motor it has a surge current of 5x to 8x times rated average.

Normally a resistive load only @4A needs almost at least 8 cycle time constant. or RC= 10x 1/100Hz= 1/10Hz ot 100ms time constant.
Using Ohm's Law 12V/4A=3 Ohms thus the demands for C from this type of supply are RC= 0.1sec or C = 0.1/ 3Ohms= 33,000 uF.
Then you need low ESR caps in parallel with this.

That's why I suggested a battery they are thousands of Farads. It can be float charged by your power supply to 13.8V

Although a better choice would be a SMPS such as a 350W PC PSU. ( almost free) using the HDD connectors.
 
"I purchased a CanaKit "

You either built it incorrectly or the parts are wrong or faulty.
 
Thanks Colin. The "kit" was put together and all I did was plug it in. But thanks for bringing up the thread as I just realized I unintentionally did not thank Tony for his detail and very informative reply. I believe he was right on the money and though my PWM is now no more, I was able to salvage four mosfets out of it:cool:
 
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