Need help with Speed Controller

[Snowman2]

I am in need of help. I have a high pitch singing sound coming from my cart. It happens when I have been running for a while with 3 people on it or when I go slow "stop and go". It only happens at the end of my ride, so I believe its heat related. I am thinking its my speed controller, but it has been running fine for 3 years without a hitch and now its starting to have this problem.

This is my set up...
2001 Ezgo, 36 volt Trojan Batteries, 4 years old
500 Amp, GE speed controller, replaced 2012
New Heavy Duty F/R switch & 800 peak/300 amp solenoid
Jakes lift kit with 22 inch tires, running on flatland in Florida
Rear stainless seat mount
4 gauge wire running all batteries and throughout
Cart runs in high 20s speed and has a 8:1 gear in the rear end

After replacing the solenoid, and test run....the temp on the wires from the batteries to the speed controller were 170..!!! The motor temp was 110

I am thinking of replacing the 4 gauge to 2 gauge from the batteries to the solenoid and so on...solenoid ....speed controller....motor....

My question is .....Is my speed controller going bad ? The shop is suggesting a Curtis 2 speed, 500 amp so I can control the low end and flip the switch to high end.

All I am wanting to do is solve the heat issues and stop the singing sound....

Any input would be great....

Thanks in advance...

[scottyb]

Which drive system is the Ezgo?

[Snowman2]

Its a series cart.....it has a high speed torque motor...6 hp.

[Snowman2]

I was wrong its a DCS cart....it has the F/R switch mounted between the two riders.....Sorry Scottyb....I was not sure of that part.....

The singing noise happens at the end of the ride and goes away when it is at full throttle, but it you back off the throttle it starts to sing again. If I let is sit for 20 minutes and it cools off the singing goes away.....

Any help would be great.....

[Snowman2]

Scottyb....I just looked a previous post of yours explaining the different carts and mine is a Series....it does not have a tow switch and the F/R is on the right in front of the controller

Sorry for the confusion....

[JohnnieB]

I'm a bit surprised the motor didn't get hotter.

But that could be due to loosing so much power in the cables. (Hot cables = lost power to motor).
Ideally, the high current cables shouldn't get more than about 10°F above the air temperature.
With your setup (500A controller, aftermarket motor, 22" tires, 8:1 gears and a rear seat with a 36V battery pack), you probably need 2Ga or heavier for all 13 of them.


If the pitch of the whine gets higher with cart speed, I'm more inclined to believe it coming from the differential (or motor) than the controller.
Controllers can whine, but the pitch doesn't change with cart speed and it is too high in frequency for most people to hear.

What oil are you running in the differential?
If it is SAE 30 motor oil, it is thinning out as it warms up.
I use SAE 85W-140 gear oil in my differential.


What is the Make/Model of the motor?

With your tire height and gear ratio, your motor is only turning at 3300 RPM when your cart is going 27 MPH, so a High-Torque motor may be better suited than a "high speed torque" motor.


BTW, the max temperature (measured at the case) for a motor with Class H insulation is 239°F and the motor is the only thing that should be getting hot. Controller and solenoid will only get warm and the high current cables and F/R switch shouldn't warm up very much.

[cartattach]

A set of 2 gauge welding cables will reduce temperatures significantly in a cart pulling big amps. I've seen 4 gauge get torched to the point of becoming brittle and failing where 2 gauge don't even get hot.

[scottyb]

Originally Posted by cartattach

A set of 2 gauge welding cables will reduce temperatures significantly in a cart pulling big amps. I've seen 4 gauge get torched to the point of becoming brittle and failing where 2 gauge don't even get hot.

Are you using 2g with your 400a controls?

[scottyb]

Originally Posted by cartattach

A set of 2 gauge welding cables will reduce temperatures significantly in a cart pulling big amps. I've seen 4 gauge get torched to the point of becoming brittle and failing where 2 gauge don't even get hot.

Are you using 2g with your 400a controls?

[cartattach]

No I'm not using a 400 at this point, I'm running a stock 1510. But as I see above, JohnnieB is using them on his 400.