开云体育

I'm restoring a 1980 Comutacar, and I'm stuck on a problem: While the car can power itself forwards and backwards in my garage, it has very, very little torque. It can not make it up my driveway, which is about 2" of elevation over 15 feet. When testing the driveway climb, the motor pulls about 350A from the controller (with a 48V battery)

The specs on the car are as follows:

• Curtis 1209B-6402 controller, this is a remanufactured controller, and I've tested it with a string of lights, so it's good.
• 4 12V deep cycle batteries.
• The motor is the stock 6HP GE field coil motor.
• Brakes are fine, I can turn the rear wheels with my hand
• There's no voltage drop anywhere in the system, and all the wiring looks great (cool) when I run it for an hour and look at it with a FLIR camera.

, which covers most of the troubleshooting so far.
The setup for the car is 48V batteries into the contactors (which are wired up correctly), into the controller, and out to the motor. I've had a few people look at this, compare it to the controller manual, and no one can find anything wrong with the wiring. I took the motor into a shop to get inspected/diagnosed, and that came back fine. The motor, as much as I can tell, is fine.

Running the car on jacks makes the wheels spin, quite fast, actually. About 80mph per my laser tach. In this state it draws ~40A with no load, peaking to about 100A at startup. For the driveway test, the controller is pulling ~350A and honestly I have no idea where it's going

I've talked to a few people and there seems to be two theories for fixing this.

1. Somehow, the field coils in the motor aren't clocked right. The symptom of this is the car should have more torque in either the forward or reverse direction; I have not observed this. Also, there's no real way to adjust the 'phase' between the brushes and the field coils. I could swap it 180 degrees, but that would just be the same.
2. A competing theory is that something is wrong with the diff / transaxel. Here, I have nothing. I flushed the fluid in the diff and replaced it with new oil, so *that's* probably not it. Could it be the bearings? I don't know. The wheels spin freely, and I really can't find a good pic of how the diff is put together (the scan of the citicar manual I have is lacking in this regard).

So that's the problem. Any ideas? Anyone have a diff/rear axel for sale?

Frankly reading all of this my gut feeling is either you don't have 48v from the batteries or not getting the full current from the batteries. I don't see where you say how old the batteries are.? First I'd use a clamp on amp meter and measure the amps on the output of the controller. And at the same time measure the DC voltage to make sure you have 48 volts. I would test these things while going up your driveway.? If these things test good, then I'd move to the motor.? I remember something about motors armature becomes magnetized over time.? Looking at the pictures, the motor looks in poor shape.? I'd take the motor to a golf cart repair shop and have them check the motor under load. They should have the tools to evaluate the motor

Here is troubleshooting of the controller??

I've tested the batteries, voltage, and current on jacks and under load. Everything there checks out -- no voltage drop when it's running, and the motor pulls about 350A from the controller when it stalls out on the driveway. The batteries are new and charged; got that from O'reilly. Cables are good, 0/2 gauge wire.

The suggestion of a golf cart repair place is a good idea; I'll look into that.

are you reading volts at the motor? what?

high current & low torque, sounds like weak motor field, shorted?

I asked your question to a buddy that use to work and rebuild these types on motors and he says from the pictures and what it is doing it sounds like a bad commutator.
You didn't say where you are but he suggest Eurton Electric in Santa Fe Springs CA 800-423-4789??

Since this car has a grounded frame, I'd be suspicious of the brushes. When I got mine, the cheap, thin phenolic the brush mounts were fastened to was broken and one brush was touching the frame.

You can see here what I did to my motor to make it ready for 72 volts/ 1000 amps.

I'll bet that the almost foil-thin copper bus bar brush interconnect has burned out, delivering current to just 1 set of brushes and not two.

I'd also highly suspect that controller. Curtis controllers are pretty much junk. They use multiple small power transistors so there can be a partial failure and it continue to operate. I tossed mine in the garbage and replaced it with an Alltrax 72500 controller with a controller bypass contactor.

John