Possible causes for motor to cut off during acceleration?

[MrJo]

Hello!
I am currently completing my second car conversion, but now I have run into problems. The car is a Saab 99 from 1972 and the engine and controller I have used comes from a microvett (Fiat with ansaldo electronics).
The motor revs as it should in neutral, but under load, when I try to accelerate (over 40ish km/h) it will just cut out.

What could be the cause of the motor cutting out during acceleration?

What I could think of is, bad connections from battery leading to huge voltage drop, one or more bad batteries which will die when trying to drain to much amps, or bad cables to the encoder causing to much noise at high rpm and current

What else could cause this problem?

[arber333]

Do you get overcurrent event? Then it is usually encoder problem.
What kind of motor is that? ACIM?
I remember Ansaldo motors. They were 30kW liquid cooled ACIM yes? Try to inspect encoder for faulty GND shield connection.
Maybe you would want to replace sensing cable with Liycy cable with shield.

Hm... do you use motor with original controler? Maybe they had a speed limit installed because of some city regulations?

[MrJo]

I have no idea, I don’t get any information from the controller. I have some sort of old dos software which connect to the controller over rs232 but the information in it seems limited (or maybe it is that I don’t know how to use it, it is Italian (which I don’t speak))
Yes 30kw acim motor.
Thanks for the tip! I will check the shield. The cable is kind of long, like over a meter, much longer than I need.
Is the length of the encoder cable a big issue for the noise?
I will shorten it anyway.

I use original controller, but I have “nothing” connected to it. The controller don’t know the vehicle speed or which gear it is in.

However, the problem seems to be happening at kind of at a certain rpm (problem happens at lower speed in lower gear)

[MrJo]

After more troubleshooting I feel like I'm even more lost... I checked the encoder shield and it seemed to be correctly connected to ground.
The motor cuts directly on all gears if the throttle is used aggressively, if used very very very carefully it is possible to drive the car at slow speed.

I tried to measure the high voltage at the controller but both voltmeters I tried just started to flicker as soon as the motor started to spin, is this normal?!

I also tried to measure the current going to the engine as it cuts of, I got it to around 40A, so not much at all. The batteries I'm using can handle 280A.

I can't seem to get like a sinus curve showing the encoder signal in the software, but I can get a rpm signal and a signal showing the throttle pedal (both looks very nice when revving in neutral). I haven't been able to look at the signal as the motor cuts (due to lack of laptop with working battery and windows xp)

Could it some programming error?? Is there usually some kind of parameter which would cause this problem if wrongly tuned? Like if the motor rpm is not increasing as fast as it should depending on accelerator position or something (?!). There are 99 changeable parameters in the controller .....
I have attached a file that should explain the parameters (translated to english from italian), I have no clue which parameters which could maybe be linked to my problem. Maybe someone knowledgeable could help out?

[arber333]

I have seen similar error with one other ACIM motor. Inverter cut off at 150Arms. I thought it was faulty Igbt. But no finally we disassembled the motor and found one phase was shorted to casing. There were evidence motor had been under water. We had to get that motor rewound.
Maybe you want to inspect both sides of the motor winding.

[Jack Bauer]

Let me save you two years of pure frustration ending in a blown inverter. Get that motor out of your car as quick as you can.