More information on stepper-motor temperature ratings and effects When in doubt, consult manufacturer documentation and ask motor-maker application engineers about allowable motor operating temperatures. This means that a motor can either feel quite hot yet be running perfectly fine or - even more deceptively - insulation makes it feel as if nothing is wrong. Not only can this be dangerous (because motor surfaces can get hot as well as pose electrical hazards) but it’s also a misleading technique - because motors are insulated to prevent them from becoming hotter than allowed by applicable safety standards. It’s impossible to tell how much hotter a stepper motor has become simply by feeling its surface. Note that this provides the increase in temperature internally. Notice the decreased performance as the motor temperature rises: This is a simplified representation of changes that occur in motor performance at elevated temperatures. A simplified graph below shows how a motor’s performance can change at elevated temperatures. However, actual values vary with temperature.Īs temperature increases, so does resistance - just as the torque constant and voltage constant decrease. So when reading performance and torque curves, determine whether the curves represent behavior at room temperature or maximum rated temperature.Īfter assembly, a motor’s theoretical torque constant K T and voltage constant K E (as well as terminal resistance R m) are fixed. Read the FAQ: Aren’t heat and noise common stepper motor problems? for more information on this. The main caveats here are that larger motors can be louder can transmit higher EMI and RFI than smaller options are costlier than compact alternatives and can have torque-to-inertia ratios than are sometimes prohibitive to speed.Ĭomplicating matters is that current overdraw can also overheat motors. Bigger motors keep cooler than smaller equivalents for a given job. One solution is to specify a larger stepper motor.
However, undersized motors are at risk of excessive heat (not to mention sluggish acceleration if not total stalling). In fact, most stepper motors are designed to operate at relatively high temperature without issue - even to 90° C in some cases. Edited by Zak Khan || Stepper motors like other motors deliver different levels of performance at different temperatures.