Linear actuator motors getting very hot with roboclaw
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Basicmicro Support
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- Joined: Thu Feb 26, 2015 9:45 pm
Re: Linear actuator motors getting very hot with roboclaw
Motors heating up significantly when idle(actually idle, not holding a position against force) can be caused by large current ripple in the motor. This is an indication the motor inductance is to low for a 20khz pwm in Locked Antiphase mode. Switching to Sign magnitude should elliminate this heating.
Note that Sign Magnitude has the disadvantage of not being able to read motor current draw when at very low duty cycles(5 to 10% or less). This is caused by blanking of the current sense input when the PWM pulse edges are too close to take a clean current reading. Locked antiphase doesnt have this problem because there is alwyas a PWM pulse with atleast 50% duty when using locked antiphase pwm mode.
Note that Sign Magnitude has the disadvantage of not being able to read motor current draw when at very low duty cycles(5 to 10% or less). This is caused by blanking of the current sense input when the PWM pulse edges are too close to take a clean current reading. Locked antiphase doesnt have this problem because there is alwyas a PWM pulse with atleast 50% duty when using locked antiphase pwm mode.