How hot should a motor get?

[JohnnieB]

Estimating an object's temperature by touching it with your fingertips is very subjective to say the least.

Accustomed to routinely handling hot horseshoes, a farrier might be able to replace a 250W incandescent light bulb immediately after it burns out, while an equine photographer will probably have to wait for it to cool.

Motors get hot because the amps passing through them not converted into motion are converted to heat and the hotter the motor runs, the sooner it will fail. However, motors with Class-H insulation are designed to tolerate fairly high temperatures, up to 239°F measured at the case, and still have a reasonable lifespan.

[bjbbiker]

Ok I'll go buy a heat gun. What's A normal operating temp and what's one for concern? You said 220 is borderline too hot and then later 230 is acceptable.

[scottyb]

Originally Posted by bjbbiker

Ok I'll go buy a heat gun. What's A normal operating temp and what's one for concern? You said 220 is borderline too hot and then later 230 is acceptable.

Again - if you are going to ride at 220º and not at 230º you are probably still going to get into trouble. You really want to stay away from the limits of rpm and heat if you want these motors to survive a long time.... pushing the limits is equivalent to driving your cart at 120 mph everywhere.

[bjbbiker]

I shave with a mach3, so driving that speed is normal to me! Motor limit on a stock 48v is 6k or 6.5? Also when I plug in the software will it give me previous data or only look at what's currently happening? It's not like a cars onboard computer and can tell you when it missed a "shift" or anything that is it?

[Sir Nuke]

Originally Posted by scottyb

pushing the limits is equivalent to driving your cart at 120 mph everywhere.

BUT BUT BUT that is SOOOOOOOOOOOO much fun!!

[Volt_Ampere]

The software only logs data when you set it up to do so. You can save it to a file and view it later. To do this, you need the Alltrax app loaded on your laptop and your laptop connected to the USB port. I say laptop but a PC would work but it's kind of hard to drive your cart while connected. :-) I put the laptop on my seat with the monitor set to log to a file and then do a test run. Afterwards I save the file. It saves to a .csv file so you need to load it into something to view it.

[JohnnieB]

Originally Posted by bjbbiker

Ok I'll go buy a heat gun. What's A normal operating temp and what's one for concern? You said 220 is borderline too hot and then later 230 is acceptable.

Originally Posted by bjbbiker

I shave with a mach3, so driving that speed is normal to me! Motor limit on a stock 48v is 6k or 6.5? Also when I plug in the software will it give me previous data or only look at what's currently happening? It's not like a cars onboard computer and can tell you when it missed a "shift" or anything that is it?

There are no magic numbers for either temperature or RPM.

Theoretically, if a cart motor will last for 20 years while operating at 220°F, it will only last about 15 years running at 230°F. In general terms, increasing the operating temperature by 10°C (18°F) halves the life expectancy, but getting a motor manufacturer to tell you what the life expectancy of one of their product is, while be a miracle.

You'll run into the same brick wall looking for a RPM "limit". All you can get is a "Maximum Recommended RPM" which is probably influenced as much by accountants and lawyers as it is by the engineers.

I asked about how fast I could spin my motor (listed below) and received a different answer from two different engineers at D&D. One said 6.0k while the other said 6.5k and when my cart is at its top speed on level ground, it is spinning at nearly 7.0k, so I seldom drive my cart at top speed.

Save a data log from your XCT and the column labeled "Speed" is the motor RPM, so you can find out how fast you have been spinning your motor. Or if you know the tire height, differential gear ratio and cart speed, you can do the math and determine motor RPM.

[gornoman]

Originally Posted by gornoman

By your description I'm gonna say it was about 120 degrees which is fine.

Originally Posted by gornoman

Hey, I was guessing, LOL.

What I meant by guessing was the actual temperature. If you can leave your hand on it for twenty seconds it should be within the safe operation zone.

[cgtech]

This does not apply to all motors by any means, but the Ezgo RXV begins to de-rate power at 120°c motor temp, and is totally done moving under its own power at 150°c.

[scottyb]

That sounds like a pretty wimpy motor. My boots get hotter than that!?