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Author Topic: Stepper motors-how warm is HOT?  (Read 3308 times)

garymck

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Stepper motors-how warm is HOT?
« on: May 26, 2015, 23:02:14 »
Hi Tom,

I have just swapped my stepper motors to some with a lower current requirement as the original ones were causing thermal shutdown despite having large heatsinks attached.

The new ones have the following specs:
Manufacturer Part Number   17HM15-0904S
Motor Type   Bipolar Stepper
Step Angle   0.9°
Holding Torque   36Ncm(50oz.in)
Rated Current/phase   0.9A
Phase Resistance   6.0ohms
Recommended Voltage   12-24V
Inductance   12.0mH±20%(1KHz)

I have set the current limit by measuring vref - set this to .42 volts, so the motors should be limited to a current within their specs. The driver chips barely get warm, however the motors get very warm - not too hot to touch, but about "cup of coffee" warm.... Is this OK? Don't want to damage the motors. Did notice that limiting the current to below the motors specs caused microstepping to become less smooth..

cheers
Gary
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TCWORLD

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Re: Stepper motors-how warm is HOT?
« Reply #1 on: May 27, 2015, 00:24:27 »
With the current limit set accurately as you have done, you shouldn't damage the motors. Some motors get warmer than others. According to the datasheet of those motors, they can withstand a temperature rise of up to 80*C, so it is probably quite normal for them to be running warm.
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Tom Carpenter (AstroEQ)