Electric Motor Problems !!!

[Snowman2]

I have a 2001 Ezgo Electric cart (36 volt, Raptor Motor, 500 Amp GE Speed Controller) and had a strange noise come from the motor today.

I was on a ride for about 1.5 hour and was at medium to low speed with 4 people on the cart. At the end of the ride the motor started to make a high pitch whining sound when I was on the accelerator. Once I got home I noticed the speed controller was warm and so was the motor.

After I inspected the cart, I took it for another ride and the sound did not return.

Question....Is it heat related ? Why would this sound happen ? Is the motor going bad ?

Any help would be great !!

Thanks in advance

Snowman

[remac]

Snowman

From what I've read, slow speed or four people takes more Amps.
You were doing both, that would explain the heat.
Hour and a half might have been close to the end of your batteries' capacity.
Depending on how full a charge you had to start.

What batteries do you have, what is their AH rating and how old are they?
What was the pack voltage when you finished the ride,
and what were the individual battery voltages.

[Sir Nuke]

snowman.....you said that the motor and controller were WARM.....could you hold your hand on them? if so, that is ok, as they were only WARM, not hot. I have the same motor as you.....and a 500A controller.

[Snowman2]

Remac, I have Trojan batteries, 105 I think. The batteries are 2 years old. I had a full charge when I left and came back with about a 2/3 left. I did not check the pack voltage or the individual batteries (wish I would have).

Sir Nuke, the motor was warm but the speed controller was hotter. I could touch the controller but just for a second.

I have never heard that noise before.

Is there a problem with my motor or is this just what happens when the cart is run a long time at low speeds with low bats ?

[Sir Nuke]

Originally Posted by Snowman2

Remac, I have Trojan batteries, 105 I think. The batteries are 2 years old. I had a full charge when I left and came back with about a 2/3 left. I did not check the pack voltage or the individual batteries (wish I would have).

Sir Nuke, the motor was warm but the speed controller was hotter. I could touch the controller but just for a second.

I have never heard that noise before.

Is there a problem with my motor or is this just what happens when the cart is run a long time at low speeds with low bats ?

well I really don't know about your controller, as I don't have any experience with the one you have.....I have a Alltrax SPM 48500 which has a built in cooling fan......

as far as your motor goes, I bet its just fine. I have ran mine 25 miles STRAIGHT at full throttle before when doing some testing......and never had any problems.

[remac]

you said '2/3 left' - sounds like a bar graph meter
other folks say those are not reliable, digital volt meter is best

[kellybell]

Originally Posted by remac

you said '2/3 left' - sounds like a bar graph meter
other folks say those are not reliable, digital volt meter is best

I agree with that! Ask me how I know......

[JohnnieB]

Originally Posted by Snowman2

..............I was on a ride for about 1.5 hour and was at medium to low speed with 4 people on the cart. At the end of the ride the motor started to make a high pitch whining sound when I was on the accelerator. Once I got home I noticed the speed controller was warm and so was the motor.

After I inspected the cart, I took it for another ride and the sound did not return.

Question....Is it heat related ? Why would this sound happen ? Is the motor going bad ?...............

In addition to what the others have said, the max allowable case temperature on your motor should be about 115°C (239°F), so if you were able to touch it more than a fraction of a second, it probably wasn't overheated.

I'm not familiar with the controller you are using, but comptrollers typically run cooler than motors.
Of course, running slowly for a long time with a heavy load might have done it.

As for the whine while accelerating, sounds like you might have gotten the oil temperature in the differential a bit hotter than it normally gets and it thinned out more than usual.

You've upgraded most of the drive system, so you might want to consider upgrading from motor oil to gear oil in the differential, or at last add a little STP or other supplement to the motor oil.

[cgtech]

Many times a high pitch whine that varies with motor speed are coming from the armature bearing at the cap end of the motor. But, most of the time when you have a armature bearing going bad the noise will be back the next time the motor is warm.