"Electromotive Guru" wrote in
message reenews.net...
I agree much with Default, yet there is one general rule for any
induction motor: They are not variable speed. You can select
different speeds based upon the wound poles, but to cause the motor
to slip excessively is not an operable condition. The only way to
safely adjust the speed of any induction motor (aside from
shaded-pole) is to reduce frequency and voltage amplitude on a
measured scale.

Am I right in thinking the RMS voltage should be proportional to the
frequency when this is done?