I mean basically the PWM is causing the motor to run, stop, run, stop, run, stop at different intervals, wouldn't it make a very uneven ride>?
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In what context? Under what circumstances? In fact, what are you talking about? – Jan 28 '14 at 07:54
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2This question appears to be off-topic because it is belongs on Electronics.SE – MSalters Jan 28 '14 at 11:40
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The PWM switching frequency is always so high that the inherent inertia of the load ensures a smooth behavior.
For example, for PWM-controlled computer fans, the PWM signal is around 25 kHz, while the fan rotates at 200 - 2000 RPM. No time for the fan to slow down between PWM pulses.
There are loads that can tolerate a slower signal: For an electric stove with big metal hotplates, a PWM frequency below 1 Hz (e.g. just few times a minute) is enough.
Chris
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i am thinking more of a PWM controlled step motor, where the RPM may be low to archive higher torque, in that case, a digital PWM may have a frequency under 100Hz, would that not cause a problem? I heard that a sine wave may be more suitable than PWM in this type of application, but again, a sine wave also have the effect of pushing the motor gradually instead of a linear motion – user97662 Feb 01 '14 at 05:01