Testing of the Motor and Finding Out Why EVE Got Bankrupt

This week we wanted to test the motor and controller.

Our first problem was that we had not gotten our batteries yet. But Simon went on a hunt and managed to get a hold of some batteries. We still were missing two so we had to borrow our car batteries as well. 

We tried to set up the controller but because we did not get a manual for the controller (the company EVE, went bankrupt) it was hard to know how the inputs should be connected. I had earlier opened the controller so i could reverse engineer it. The controller had a 3kW charger (for the battery bank), a small charger (for the 12V battery), 2 fuses, 3 relays and the controller unit. The controller unit is a Curtis  1238 controller and that we had a manual for. So i could with the help of the Curtis manual figure out some of the inputs and outputs, but many of them still depends heavily on how EVE programmed the Curtis. We could get the computer program that is needed to access the Curtis from a PC, but it cost a lot and it is not in the budget at this time.   

When everything was set up we held our breath and twisted the key, and nothing happened. We tried a couple of things but nothing helped. We took a break for the day and I went home to study the Curtis manual to see if I could understand what was wrong. 

The next day we tried again and I had actually found something that we missed the first time. It was an input that is usually programmed as a safety latch, so we put 12V signal on that input and then the master relay said click. The motor was still not turning, but it was progress. 

Now the Curtis flashed a error code, and according to the manual it was signaling "motor short circuit". Simon started to measure if there actually was a short circuit and I consulted the manual. After a few measurements Simon cried out that something is very wrong here.   

What we found was the most horrifying, idiotic mistake I have ever seen. But to understand the problem we need a little back story.

When we got the motor and controller we also got a few switches, signal cables and 3 shielded 50mm² motor cables. EVE had already put on cable terminals and heat shrink tubing with the yellow/green earth cable sticking out from the heat shrink tubing.

When you have a AC motor that is controlled by a frequency controller you must have shielded cables between the controller and the motor. You also have to ground the shield in both ends of the cable, if not you will get a lot of interference in the signal cables nearby.

The common way to do this is to take a yellow/green earth cable and stick it in next to the shield, and then you earth the cable. 

So when we saw the cables we said:

-"Great that they already have prepared this for us".

Nothing weird here, just a ordinary motor cable.

So we connected every shield cable together and bolted it to the chassis.

Motor cables connected to the controller and the earth cable is ready to be bolted down.

Okay so back to the problem Simon found.

He noticed that the cables was indeed short circuited and it was because the earth cables was not connected to the shield but instead connected to the motor cable itself. 

WHY!!!

It is so stupid that i almost got brain cancer. EVE must have been employed by idiots.

Not a surprise that EVE got bankrupt.

We are so happy the Curtis controller is protected against short circuit.

So after solving jet another problem EVE manage to create we could at last test the motor.

Ready for testing

Weeee, it works. We are so happy that it is working.

It is alive, ALIVE!

Next week we do not have any lectures in school so we are going to mount the motor and controller in the car and schedule an appointment for the blasting and paint work.

/Oskar