At 02:14 PM 7/6/2006 -0400, you wrote:
>Low voltage PMDC motors also have low inductance. I would expect to find
>high ripple current. This may or may not be a problem depending on the
>rest of your system. I would measure the ripple at whatever PWM
>frequency you use and increase that frequency if the ripple is too much.
>--
>Martin K

Or, if the motor is of a type that has very low inductance, just add a
series inductor to keep the PWM frequency reasonable. Needless to say(?)
switching losses will tend to be higher to begin with, all other things
being equal, just because of the low duty cycle, and thus low on time
in relation to (fixed) switching times.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com




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