I would like to know what are the standards for maximum audible noise level in the machine room. We have an PWM AC drive, which is making around 75 to 82 dB noise. Is this acceptable level. It is measured at 1 meter distance from the motor. How to reduce this ??? PLEASE HELP

-- N.B.Patil (nbpatil@technologist.com), September 04, 1997

Answers

one way to reduce the audible noise is to increase the switching frequency which is user programmable in most of the new PWM drives. Typically the switching frequency will range from 1kHz to 15 kHz and the switching frequency is directly co-related with audible noise. Increasing the switching frequency will reduce the noise, however there are some issues with bearing fluting at >10 kHz swithcing frequency that you need to be aware of.

-- Arshad Mansoor (mansoorar@aol.com), December 09, 1997.