Paul & Sabrina's cheap DIY 144v motor controller

[twotires]

Finished my controller this weekend. Don't have traction batteries to see if it will push the car, yet, but stay tuned.

Thanks, everybody for all the help.

Michael

[electricstorm]

Originally Posted by 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

Thanks for the info Michael!

How many resistors did you use, what values were they, and where did you connect them to on the control board? I am assuming you tapped each point in the divider network to simulate different current levels.

Jim

[twotires]

Electricstorm,
There are 4 pins leading from the control board to the LEM HASS current sensor - pin 1 isn't even hooked up to anything, you can omit it. Pin 4 gets +5V and pin 3 is gnd. Pin 2 is where the output comes back from the sensor. I hooked up two 100k resistors (I think they were - basically any two resistors of equal value), one from pin 4 to pin 2 and one from pin 3 to pin 2. This splits the +5V in exactly half so the 'output' looks like 2.5V so the controller thinks it's hooked up and getting a signal back. Yellow light doesn't light (assuming you have no other problems, unlike mine!) and you can move on to the next test.
Are you near the RTP?

[electricstorm]

Michael,

I will try your suggestion about the voltage divider once I solder in the Cincon DC-DC converter.

No, I am not near the RTP. I live in Concord, just outside of Harrisburg, NC. You are probably about 2-1/2 hours or so away from me.

[MPaulHolmes]

The AC control board is without mistake! But this is the DC controller section! dang it. haha. The driver boards for the AC work perfectly, pounding the igbts into turnoff harder than that one ranger pounded that guy in Texas (actually not quite as hard as that). The power section is perfect. I'm done bragging now. Now it's time to add a load of a motor.

As for the DC, I'm fairly certain that the new and improved "solder temperature for 5 seconds" approach will work and everything will be wonderful. yay.

[MPaulHolmes]

I tested out that big inductor (48 pounds) with the nichrome wire (4 strands of 12 gauge each). The nichrome was 0.14 Ohms and was in a big bucket of water. It was just liike a motor! Perfect current control. I could even ramp up the duty to 100%. I tested it out on a controller kit that was sent to me to test. At 100% duty, at 24v it was using about 170 amps. I also ordered some more Nichrome so I could do higher voltage testing, and keep the current from going into the stratosphere. It really works as a good motor simulation. Plus you don't have to worry about the motor running away when testing new controllers that fail ON.

[toddshotrods]

Hey everyone - if at first you don't suceed... I posted this in the wrong thread the first time. Take two:

This is awesome! I am planning to build a Open Revolt controller for my hybrid hot rod. I have an 11" GE SepEx motor to drive the front wheels and the idea of using the AC setup to control the arm and field from the same controller is more than intriguing.

Will there be, or can there be, two control boards to enable individual and/or manual control of the arm and field separately?

[dave koller]

[XmodAlloy]

Paul, you may want to buy a 500 amp slow blow fuse so that you don't liquefy your NiChrome wire assembly when you have a controller run away on you.

-Don

[isaac_alaska]

a fusible link and a fire extinguisher would be cheaper than a high voltage 500 amp fuse