Motor issues

[CFD Fireman]

Ok, I am losing my religion here. First the background. I have a 1988 ezgo with the toaster oven that has been upgraded to 48V. The other day when I backed out of my garage and switched back to forward the motor stopped and the only thing it was doing was making a chattering noise as was the solenoid. During troubleshooting I took the motor out and tried to bench test it. I hooked A2 to S1 and applied voltage across A1 and S2. The motor only makes a chattering noise and it is locked down so it can not even turn by hand. With no power it turns freely by hand. I tested it out with an ohm meter and determined I has a short from the stator to the chassis of the motor. So I found a used replacement motor locally. When I picked the motor up, the guy I boght it from hooked it to a 12V battery and verified that it indeed runs. When I got home and tried it in my cart I got the same result. I removed the motor and attempted to bench test it as well. No mater what combination of connections I try it still will not run. Turns free when not on power but locks down under power and chatters. With a meger I have tested each coil independently, results that they have good continuity. I have tested each coil to each other with no continuity. As well as each coil to the chassis with no continuity.

Am I missing something here? The motor checks out. I saw it run before I brought it home. And under a normal bench test it should run.

Someone help me out here please I have worked as an electrician for years and this defies all I know about motors.

Any help woul be appreciated.

[Great white north]

First off we need more info. On what style of cart you have .
Is the front / reverse switch on the dash or down by your knee ?
This will determine if you have a series or sexpex drive system
Check out the stickeys on electric EZGO on the site -- read them , that will get you started
There could be a good chance your original motor is not the problem
Cheers !

[yurtle]

Originally Posted by CFD Fireman

Ok, I am losing my religion here. First the background. I have a 1988 ezgo with the toaster oven that has been upgraded to 48V. The other day when I backed out of my garage and switched back to forward the motor stopped and the only thing it was doing was making a chattering noise as was the solenoid. During troubleshooting I took the motor out and tried to bench test it. I hooked A2 to S1 and applied voltage across A1 and S2. The motor only makes a chattering noise and it is locked down so it can not even turn by hand. With no power it turns freely by hand. I tested it out with an ohm meter and determined I has a short from the stator to the chassis of the motor. So I found a used replacement motor locally. When I picked the motor up, the guy I boght it from hooked it to a 12V battery and verified that it indeed runs. When I got home and tried it in my cart I got the same result. I removed the motor and attempted to bench test it as well. No mater what combination of connections I try it still will not run. Turns free when not on power but locks down under power and chatters. With a meger I have tested each coil independently, results that they have good continuity. I have tested each coil to each other with no continuity. As well as each coil to the chassis with no continuity.

Am I missing something here? The motor checks out. I saw it run before I brought it home. And under a normal bench test it should run.

Someone help me out here please I have worked as an electrician for years and this defies all I know about motors.

Any help woul be appreciated.

Don't try and bench test the motor if it isn't installed, as it only has one bearing. The other bearing is in the rear end.

Links:

Owner's, Parts, and Service Manuals:
http://www.buggiesgonewild.com/elect...g-manuals.html

Dana Axle:
http://www.buggiesgonewild.com/attac...5-28148g01.pdf

[scottyb]

Series motor test ... curious what the battery pack voltage drops to when you try to go & the chattering begins ?

[Volt_Ampere]

These motors can not be bench run!!!!!!!!!!!!!!!!!!!! The armature will hit the stator and damage things big time. The front bearing is not part of the motor!

[CFD Fireman]

The F/R switch is by my knee and it is a series wound motor. By bench test I meant that I hooked it directly to the batteries bypassing the other electronics while mounted in the cart. I have not tested the load drop when hooked up but I did hook it directly to the charger with the same result. At this point I am sure there is a motor problem because I cannot get it to run with just the batteries and the motor. Any other suggestions?

[Volt_Ampere]

I agree with your diagnosis. Bad Motor. Could be brushes but often there is damage to the commutator when the brushes fail to a point that the motor doesn't run.

[gornoman]

Originally Posted by scottyb

Series motor test ... curious what the battery pack voltage drops to when you try to go & the chattering begins ?

Originally Posted by CFD Fireman

The F/R switch is by my knee and it is a series wound motor. By bench test I meant that I hooked it directly to the batteries bypassing the other electronics while mounted in the cart. I have not tested the load drop when hooked up but I did hook it directly to the charger with the same result. At this point I am sure there is a motor problem because I cannot get it to run with just the batteries and the motor. Any other suggestions?

The voltage drop under load is extremely important for any kind of long distance diagnosis. You cannot test these sparky carts without a known-good battery pack, and the way we determine if they are good is to watch and trace the voltage.