My motors are getting pretty hot...

[Hirudin]

I've got a few Keling KL23H276-30-8B motors on a Taig mill. I'm using Gecko 203Vs and a Keling KL-600-48 (48v power supply turned down to 40v) to drive them. Everything it working beautifully.

I'm concerned that my motors may be getting a little on the hot side though. They haven't got too hot to touch with my hand (and I have a low heat tolerance) but I also haven't run them for very long. Is there some point at which I should give the motors a break?

I've turned the voltage down to 40v on my power supply, which helped. I've been thinking about adding some passive cooling (I've got a bunch of heatsinks lying around). I've even thought about wrapping some copper tubing around the outside of the motors and pumping water through them. Would some kind of cooling be a good idea?

[jalessi]

Hirudin,

Do you have the correct current set resisitor installed?

I believe your steppers should be around 2 amps.

Running your steppers at 48 volts wont hurt, it will enhance the speed of your machine.

The steppers can generate a lot more heat than you think.

Your motors can safely handle 160 degrees Fahrenheit.

Jeff...

[Hirudin]

Thanks so much for your help now and in the past Jeff!

Hirudin,

Do you have the correct current set resisitor installed?

I believe your steppers should be around 2 amps.
...

I think so. I have the motors wired as bipolar parallel. I have a 68k ohm resistor in my 203Vs, which I think should give me somewhere between 4.1 and 4.2 amps.

The spec sheet for my motors (PDF)

203V resistor formula: R (in kilo-ohms) = 47 * I / (7 – I)
If my math is right...
4.2 amps = 70.5K ohms
4.1 amps = ~66.45K ohms

...
Running your steppers at 48 volts wont hurt, it will enhance the speed of your machine.
...

At the moment I've got my Taig going at 124.8 IPM without much weight on the table. That's more than what I was hoping/dreaming would be possible: 100 IPM.

...
Your motors can safely handle 160 degrees Fahrenheit.
...

160º eh? I don't think they're getting that hot... That's a relief! Like I said, I have a low heat tolerance and so far I'm able to grab and hold onto the motors.

[Crevice Reamer]

Your motors should be fine. I'm sure they are running well below temp limits. Don't forget that the 203V has idle current limiting which also helps keep motor temp down.

Now if you touch your motor with a wet finger and it SIZZLES--THEN you have a problem.

CR

[LeeWay]

About 120 degrees F is where my cutoff is for being to hot to rest your hand on for any length of time. I have one motor on my little lathe with201's that gets hotter than this. Possibly 140 F. It is still kicking fine. I would agree that 160 to 170F would need a solution. You run the risk of the magnets loosing it's attraction.

[Hirudin]

I'll prolly pick up an infra red temperature probe/tester, then crank the power supply back up to 48v, then crank up the acceleration/speed in Mach3... sweet!

[gandalf1]

I thought my motors were getting too hot so made a shroud to fit round them with a PC power supply fan to push air past the casings. Barely get warm now. I am using Nema 23 motors 5 volt, 1 amp per phase. Biggest problem is I cannot easily try a damper on the extended spindle now as there is a fan in the way.
John.

[Kelinginc]

I thought my motors were getting too hot so made a shroud to fit round them with a PC power supply fan to push air past the casings. Barely get warm now. I am using Nema 23 motors 5 volt, 1 amp per phase. Biggest problem is I cannot easily try a damper on the extended spindle now as there is a fan in the way.
John.

The motor Max Temp < 80 C

[Santa Fe Al]

Hi All,

I just got off eBay and found some panel mount digital temperature gauges that read up to 70 (158F) degrees Celcius. They are really cheap.

I'm not sure of the probe wire length, but they could be mounted tight against a stepper motor and you would have instant temperature reading letting you know how hot your steppers are.

Since it is generally agreed that steppers should not exceed 160 degrees F, this should be a shoe-in. I ordered three of them to mount on my stepper motors. Hopefully, I won't need to worry about overheating.

Al

http://shop.ebay.com/sis/_W0QQ_kwZLC...eleafcatZ40977