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Unread 18-06-2003, 01:36
Random Dude Random Dude is offline
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Well the main problem I see is that you are applying 2.5 times the rated voltage of the motor. Even if you use PWM to vary the speed of the motor the excessive power is still being applied to the motors.

I'm willing to bet that if you increase the frequency to 4000Hz you will still have the same exact problem, even if you limit the duty cycle to < 40%.

My reasoning:

At both 400Hz and 4000Hz with 40% duty cycle the .4 seconds of every 1 second (obvious but bear with me)

The reason the motors keep burning out is overheating due to the excessive power passing through them.

Now all that changing to 4000Hz would due is to apply the same power for more, shorter lengths, with pauses in between. At 4000Hz those "pauses" are ~150uS (.00015 S). That period is most likely too short to effectively radiate any large amount of the power just applied (Exact numbers would require the spec sheets of the motors)

However, even if the motors did happen to run at 4000Hz <40% duty cycle, you would definitely begin to run into problems again once you increase the duty cycle range toward 100%.



Summary:(I.E. the short version)

Decrease the voltage back to 13V.

Even that is technically pushing the limits of the motors but you have experience that they work with that voltage, so...
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