Then it would seem to be being used to create a rotating magnetic field. In this case too samll a value will lead to a reduction in full speed torque and possible speed variations, and too large a value will reduce the low speed torque (i.e. when the motor is running up). However having said that the value will be a compromise anyway and +/- 20% either way shouldn't hurt enough to notice. Lee. ________________________________________________________________________ This e-mail has been scanned for all viruses by Star Internet. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk ________________________________________________________________________