Paul & Sabrina's cheap DIY 144v motor controller

[isaac_alaska]

i don't think it's ever been socketed before....it's a good piece and the board has protection in it so there's a resistor that will burn out before the converter. the only problem i know of with the converter is sometimes soldering it to the ground plane can be hard, but i think that's been fixed since then.

[flores]

I'd say that socketing may cause more problems because of resonance and bad connections.

You can always desolder a component if it fails..

[apowers]

I have not had any problem with mine. One board is in a controller since 09, and another was in a charger. The one in the charger would run 8 to 10 hours a day for over a year not counting winter months. The control board still works but is just not being used now.

I used sockets almost everywhere too.

Alvin

[jmcginley]

I socketed all the IC's but not the Cincon. Everything's running fine!

[electricstorm]

Thanks everyone for the response.

I was mainly concerned with having to replace the Cincon should it happen to fail. But it sounds like no one has had a failure so I guess I'll go ahead and solder it in.

One other question. Can the control board be tested without the power board as far as using a scope and checking signals? Or is it best to have the whole unit assembled before testing?

Planning on doing some checking of the circuit and then completing the power board, assembling and testing with an old starter as a first load test.

Jim

[flores]

Yes. You can test the controlboard seperately with a scope.

[jyanof]

Originally Posted by electricstorm

Thanks everyone for the response.

I was mainly concerned with having to replace the Cincon should it happen to fail. But it sounds like no one has had a failure so I guess I'll go ahead and solder it in.

One other question. Can the control board be tested without the power board as far as using a scope and checking signals? Or is it best to have the whole unit assembled before testing?

Planning on doing some checking of the circuit and then completing the power board, assembling and testing with an old starter as a first load test.

Jim

for testing, i think you'll just have to hook up the current sensor. also, without any current actually flowing, the controller will just go to full on in an attempt to increase the output current. maybe if you use a really low kp and ki, you'll be able to see the transition between off and on, but i guess if it goes on and off, that means it's working.

as for desoldering, i'd recommend one of these. I've had nothing but success with mine and it's very affordable at $12.

RadioShack® 45-Watt Desoldering Iron - RadioShack.com

[MPaulHolmes]

I practiced different solder techniques yesterday for the TO-247 package backs to bus bars. I put a sample of paste on the Middle leg (it's connected to the back), and then put the component on a bar that is around 450-500 degF. It takes 5 seconds for the middle leg to melt the solder, and then I give it 5 seconds in melted state and then put it in a water bath. It cools in just a couple seconds. Here's some soldering of one of the phases of the AC controller (by the way, the skinny area in the middle is where the current sensor goes. Skinnier makes the current sensor more sensitive.:


That's going to actually be 4 igbts per phase later, but just one free (Thanks Rod Hower!!!) 50amp igbt per phase for testing.

I also ordered a 48 pound 200amp inductor that I'm going to use with testing the controller. I know I know, some resistance also needs to be added to increase the PWM duty and not just test the freewheel diode! haha. I have that covered too. This move proved necessary since my crappy motor threw some bars that the brushes rub against when it ran full tilt at around 120v. It was also rated for 24v. Man, that was friggen scary. Long story, must go to school!

[foor]

Originally Posted by electricstorm

Can the control board be tested without the power board as far as using a scope and checking signals? Or is it best to have the whole unit assembled before testing?

Electricstorm,
if you clip your oscope ground to the top of R17 (FET ground), and attach the signal probe to pin 7 of U7, you should be able to see the 12v PWM trace with period of about 60usec (~16kHz). I also set ki=20 (down from 160) to slow the pwm rise time in order to see the duty cycle changes more clearly. This can be done without the power board attached.

[twotires]

Electricstorm,
You can also build a quick voltage divider from 1/4W resistors to fool the control board into believing it's getting a signal back from the current sensor - keeps you from getting the yellow light - then scope the signals at U7 ....

Michael