Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!caen!hellgate.utah.edu!dog.ee.lbl.gov!nosc!marlin!bryan
From: bryan@marlin.NOSC.MIL (Dale Bryan)
Newsgroups: comp.robotics
Subject: acoustically quiet motor controllers
Message-ID: <1775@marlin.NOSC.MIL>
Date: 11 Jun 91 15:04:47 GMT
Organization: Naval Ocean Systems Center, San Diego
Lines: 9

does anyone know of an acoustically quiet dc brushless motor controller (120V)?
we are using 3/4 hp dc brushless motors with buil in motor controllers to
drive thrusters on an underwater vehicle.  the problem is that the motor 
controllers pwm frequency and its harmonics is radiating sound into the water.
this sound is interferring with acoustic sensors aboard the vehicle.
thanks in advance.

dale bryan
email: bryan@marlin.nosc.mil