PDS Motor temp?

[rockfordpi]

How hot should the motor be on a PDS with 20" tires after running 7 miles non-stop on paved roads with some inclines, not really hills. In my case, the motor was very hot, I could not touch for more than 1/2 second (or less) without it burning my hand.

All battery wires and terminals were barely warm. Solenoid was hot, but still working fine.

I am trying to help a guy who is complaining about range and battery life. Batteries are March 2016 and rated reserve capacity is 105 min at 75 amps. Load test gave 75 amps for 65 minutes.

Started with a full charge, pack was reading 36.4 volts after 7 miles and while cart would still move on level ground, would barely go up inclines.

I am not sure there is anything wrong here, but he guy swears that over the past couple of months his range has gone way down. Obviously the heat in the motor represents energy loss, just trying to figure out if that is normal under the condtions.

[biphase]

The controller is probably overheated and going into thermal cutback.

[rockfordpi]

Originally Posted by biphase

The controller is probably overheated and going into thermal cutback.

Would that cause the motor to heat up? The surface of the controller is barely warm.

[scottyb]

At about 225º outer case temperature the armature bonding material begins to soften. The motors continue to heat up even when the cart is left sitting to cool. I have seen temps go up 20º in the 30 minutes following a heat test shutdown.
The motor should never get so hot that you cannot hold you hand flat on the case for the count of 5 seconds. This is about 175º. I use 150º as my maximum temperature goal when testing as the 20º rise after the test raises inside temps to what I consider a safe repeatable temperature. Many temp gauges are available. The easiest to use is the harbor freight infrared handheld laser pin point type. Here we have installed a few amazon offerings > http://www.buggiesgonewild.com/elect...p-exist-5.html

You may have a worn motor - or a mismatch of components.

[Gibb]

A 1/2 second is definitely to hot. Maybe the motor is going bad or full pedal for 7 miles has something to do with it. Somebody will chime in with more questions. When you figure it out you can put a temp gauge on the motor. Reed this post.

http://www.buggiesgonewild.com/elect...p-exist-2.html

[Gibb]

Woops Scotty beat me to it while I wuz getting coffee

[JohnnieB]

Originally Posted by rockfordpi

..................
Obviously the heat in the motor represents energy loss, just trying to figure out if that is normal under the condtions.

True, heat in the motor is energy loss, but it is inevitable since motors are not 100% efficient.

Motors have an efficiency curve and are more efficient at a mid range RPM than they are at low RPM or High RPM. At WOT (Wide open throttle), series motor can probably turn 20" tire for 7 miles without getting excessively hot, but Sepex (DCS-PDS-TXT-4 motors probably cannot.

To get to its max RPM, the field current of a sepex motor is reduced (field mapping), which reduces the motors efficiency greatly and the motor get mighty hot mighty quick, and the 20" tires makes the situation worse.

Remember the drive system is designed to turn 18" tall tires and travel about six miles, or so, in 18 increments of less than 500 yards with several minutes of rest between increments. 20" tires deviates form the system design as does driving 7 miles without out any stops. Running WOT for miles instead of yards also deviates from the design.

To travel long distances with minimal motor heating, run at 80% to 90% of max speed. This will also slightly improve the cart's range.

[rockfordpi]

Originally Posted by scottyb

At about 225º outer case temperature the armature bonding material begins to soften. The motors continue to heat up even when the cart is left sitting to cool. I have seen temps go up 20º in the 30 minutes following a heat test shutdown.
The motor should never get so hot that you cannot hold you hand flat on the case for the count of 5 seconds. This is about 175º. I use 150º as my maximum temperature goal when testing as the 20º rise after the test raises inside temps to what I consider a safe repeatable temperature. Many temp gauges are available. The easiest to use is the harbor freight infrared handheld laser pin point type. Here we have installed a few amazon offerings > http://www.buggiesgonewild.com/elect...p-exist-5.html

You may have a worn motor - or a mismatch of components.

I have an infared thermometer, just could not locate it when I needed it, LOL.

I don't think it is mismatched components as everything is stock.

is it possible worn brushes or carbon build up on armature would cause this level of heat?

[coosa]

I have a couple of PDS carts and I have a thermometer similar to the one ScottyB mentioned. I have 22" tires on both and a 500 amp controller turned down to 80%. The highest temp I've ever recorded on a motor was 190, and that was after a long hard ride off road, immediately followed by a 1.5 mile wide open run down a county road. Maybe that will give you some idea of what a high temperature looks like.

I really need an aftermarket motor, but I'm pretty old so I think there is a good chance both motors will last longer than me. I plan to keep a close watch on the temp and hopefully let the next owner deal with it.

[rockfordpi]

Originally Posted by coosa

I have a couple of PDS carts and I have a thermometer similar to the one ScottyB mentioned. I have 22" tires on both and a 500 amp controller turned down to 80%. The highest temp I've ever recorded on a motor was 190, and that was after a long hard ride off road, immediately followed by a 1.5 mile wide open run down a county road. Maybe that will give you some idea of what a high temperature looks like.

I really need an aftermarket motor, but I'm pretty old so I think there is a good chance both motors will last longer than me. I plan to keep a close watch on the temp and hopefully let the next owner deal with it.

Based on your screen name, are you in Alabama? We are close to the Coosa River is the reason I ask