[sci.electronics] efficient, acoustically quiet motor controllers

bryan@marlin.NOSC.MIL (Dale Bryan) (06/06/91)

does anybody know of a dc brushless motor controller (120V) that is efficient
and acoustically quiet?  we are currently using 3/4 hp dc brushless motors
with built in motor controllers to power an underwater vehicle's thrusters.  the problem is that these controllers are radiating acoustic noise at the pwm frequency and its harmonics into the ocean.  this interferes with acoustic sensors on
board the vehicle operating within those frequency bands.  
thanks in advance

dale bryan