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  • el3ktr1k
    el3ktr1k

    Member • Oct 9, 2008

    PWM frequency

    I plan on getting a motor and controlling it with pulse width modulation. I noticed some motors don't function that well when the frequency of the PWM is too high and others work just fine. Is there something on motors' data sheets that will let me know their performance for different frequencies of PWM. Thanks for any help.
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  • silverscorpion

    Member • Oct 9, 2008

    Hi
    Yes u can get the info from the motor's datasheets.
    When u use PWM, what u are actually doing is switching an electronic switch
    On and OFF repeatedly at a particular frequency. Now, electronic switches
    like transistors can switch in times of the order of microseconds. Motors,
    being mechanical, cannot switch direction that fast. There's inductance in a
    motor and that prevents the motor from responding fast to a changing signal.
    So, if a motor doesn't work for a particular PWM, get a motor that has low
    inductance than the one currently being used. Or use PWM of a lesser
    frequency.
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  • el3ktr1k

    Member • Oct 10, 2008

    thanks. I'll look for a motor with low inductance since lowering the PWM frequency isn't really an option.
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