Overcurrent protection for controller/motor in electric vehicle

Status
Not open for further replies.
I

IamJonscranium

Member
Location
Ohio
Hey guys. My previous experience with overcurrent protection for motors and controllers has been with VFDs like AB 700 series etc.. I understand that the wire feeding a VFD must be sized according to the VFD current rating.

What I am currently working on is the motor controller for an electric traction drive (the drive wheel) on a vehicle. Due to the availability of drives for this application, each motor pulls about 175A, but the controllers have a 2min RMS of 275A.

Does my circuit protection need to be sized for the motor controller? #1 AWG in ambient?

Thanks.

ETA: DC input, AC PWM output to induction motor.
 
Last edited:
Smart $

Smart $

Esteemed Member
Location
Ohio
How does NEC requirements apply to vehicle wiring?

No expert on vehicle wiring but I see a need for more info. The short of it is need enough info to determine input watts. Then considering DC voltage (if battery powered, at low charge voltage), determine starting and nominal running current and then appropriate ocp based on that value. Wire size determination follows.
 
I

IamJonscranium

Member
Location
Ohio
Smart $ said:
How does NEC requirements apply to vehicle wiring?

No expert on vehicle wiring but I see a need for more info. The short of it is need enough info to determine input watts. Then considering DC voltage (if battery powered, at low charge voltage), determine starting and nominal running current and then appropriate ocp based on that value. Wire size determination follows.
Click to expand...

The thing is, the controller current capacity is way above the motor's acceleration current draw.

I was able to get ahold of someone here. Basically I'll size it for the MC current draw, but since the actual draw of the motor is less, I can put two motors and controllers on one fuse. That way I'll get the current protection for each one, but allow both to run on a single source.

Now the question is, can our battery terminals handle the overall current draw and wire size?

Just to answer a few of the questions you had:

Our batteries will drop at most 1V between charges.
Starting current is under 200A for 1s, and these are time delay fuses so I only need to size for the nominal current draw.
 
Status
Not open for further replies.
Top