> I know this subject has been discussed many times before,
> I have been through the archives but still find myself puzzled !!
>
> ...
>
> Well thats it - simply put, which is the best freq to drive a Dc
> motor using pwm and how to determine it ??

Short answer: a few 100Hz.

Long answer: there are lots of factors that have been beat to death here as
recently as a few weeks ago.  A high frequency heats the switching element
because it spends too much time in transition between on and off.  Too low a
frequency and the motor reacts to individual pulses instead of their
average.  An additional wildcard is audible noise.  There is no way to guess
this because it depends on things that are not specified, like how tight the
windings are held.  So after much calculations and wringing of hands you end
up with a few 100Hz.


*****************************************************************
Embed Inc, embedded system specialists in Littleton Massachusetts
(978) 742-9014, http://www.embedinc.com

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body