CC Precedent Motor Runs Forward NO MATTER WHAT

[rockfordpi]

I know controller,is damaged, just trying to understand HOW/WHY the motor runs forward only, even when in reverse and after swapping motor leads.

Background. 2015 CC Precedent

Cart was running rough. Owner tried to tap motor end for possible stuck brush and accidentally Shorted A1 and F1.

Obviously damaged controller, when I check controller output on a1-a2 and f1-f2 the polarity never reverses on either. Reverse buzzer sounds and computer shows the controller is getting a reverse signal.

So, just for the heck of it, I reversed f1 and f2 leads. Wheels still turn forward in both f and r positions.

[Put f1 and f2 back as they wereand swapped a1 and a2. Wheels still turn forward in both f and r positions.

I am testing with wheels jacked off the ground. No short between any motor terminal and motor case. No short between armature and field windings.When testing roll away, cart beeps but offers no resistance.

I can't understand how this is possible and it is driving me crazy!:

[NoleFan4Ever]

Unhook the motor leads as the short in the motor may be causing the motor direction regardless of controller signal thru F1/F2.

[WalterM6]

Just off the top of my head I would say that the transistors in the controller shorted instead of opening when he had his accident with the wrench.

[rockfordpi]

Originally Posted by WalterM6

Just off the top of my head I would say that the transistors in the controller shorted instead of opening when he had his accident with the wrench.

That makes sense, but why does the motor still run forward even after I reverse the leads oh, that's what's puzzling me

[JohnnieB]

Originally Posted by rockfordpi

That makes sense, but why does the motor still run forward even after I reverse the leads oh, that's what's puzzling me

In response to your PM. (I don't visit here much since I know very little about CC carts and have no desire to learn, but DC traction motors are DC traction motors. )

It is a mystery to me also. Maybe the people at D&D or EMP or PQ might have an answer.

My guess is there are 4 field windings connected 2P2S and the field coils in a sepex motor are designed for low amps (<50A), so shorting them to the high amps Armature output from the controller may have shorted across one half of one the series strings and the resulting weirdly shaped magnetic field caused by three field windings pulling the 4 pole (2 pairs of pole) armature in the same direction no matter which way the amps flow in the field.

The controller is easier to explain.

Here's a couple of drawings showing the motor field and brush wiring and generic sepex controller using an H-bridge for the field output.

[rockfordpi]

Originally Posted by JohnnieB

In response to your PM. (I don't visit here much since I know very little about CC carts and have no desire to learn, but DC traction motors are DC traction motors. )

It is a mystery to me also. Maybe the people at D&D or EMP or PQ might have an answer.

My guess is there are 4 field windings connected 2P2S and the field coils in a sepex motor are designed for low amps (<50A), so shorting them to the high amps Armature output from the controller may have shorted across one half of one the series strings and the resulting weirdly shaped magnetic field caused by three field windings pulling the 4 pole (2 pairs of pole) armature in the same direction no matter which way the amps flow in the field.

The controller is easier to explain.

Here's a couple of drawings showing the motor field and brush wiring and generic sepex controller using an H-bridge for the field output.

Thanks JB. If I understand correctly, you are saying possibly 4 poles, by way of a short, became 3 poles. If so, that that sort of makes sense, and is the best answer I have gotten so far. That probably explains why the motor turns, but has very little torque.

One other thing I found. Though neither f1 or f2 are shorted to the motor case per my meter, When I check voltage between f1 and the case while the motor is running, it reads 36v.

Hopefully I can get the motor off tomorrow and check it closer.