Motor insulation survival with new adjustable frequency drives

摘要

Motors connected to an IGBT adjustable frequencydrive may experience high peak voltage stress that will increase thepossibility of failure. This has become a greater problem with theIGBT-type drives. If an IGBT AFD is being installed as areplacement to an existing drive, the system setup must bereviewed to reduce or eliminate the peak voltage stress. Thecleanliness and condition of the motor being driven must beconsidered and the user should be especially careful when applyingfractional horsepower motors to adjustable frequency drives. In thespecification of new motors, the motor manufacturer should beaware of the circumstances of the system, including a prediction ofpeak voltage potential. Currently, special insulation is recom-mended for motors operating on IGBT drives above 460 v.