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Unread 16-02-2012, 19:24
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Ether Ether is offline
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Re: Voltage vs. PercentVbus

Quote:
Originally Posted by dsirovica View Post
The PWM cycle is (I believe) 50KHz
No, it's 15KHz (for a Jaguar) and 150Hz (for a Victor).

Quote:
so a DC meter will read the average and indeed show 6V
There's no guarantee that any given DC meter will read average. A true RMS DC voltmeter will read 8.5 volts. Some DC voltmeters read RMS, some read algebraic average, and some read neither.


Quote:
But that is not reality. If you use a scope, in "normal" operation, you will see a 50KHz squarewave (ignoring inductance distortion for clarity) with a 50% on/off duty cycle
The voltage waveform you see on a scope will depend on the motor, the motor controller, and the test conditions. With high inductance motors and high PWM frequency, the stalled-rotor current waveform will be DC with slight ripple.



Last edited by Ether : 17-02-2012 at 11:19. Reason: made some clarifications and added some info