Detection of corona in small coils and motors

Newly introduced pulse width modulated type drives have an inherently fast rise-time resulting in transient voltages that are much higher than the operating voltage. A need has been created for corona detection in the motors used with these drives, preferably using a voltage impulse. A simple method has been developed to detect corona levels in a small coil or motor and experiments have been performed to verify the new method. This paper explains the theory and procedures used to determine corona levels experimentally. An automated system has been developed for corona detection and is also discussed