Existing reviews of 60 hp (45 kW) VFD, 3 Phase 240V, 380V, 480V
Question is for high shaft voltage. Does bearing insulation at one side is enough to protect both bearings of motor? Why shaft grounding is required?
From:
Guest
|
Date:
27/05/2017
Was this review helpful?
Yes
No
(0/0)
Best practice is to have a good earthing system for high frequencies, then insulate both bearings and then earth DE bearing to keep shaft voltage close to ground potential. For VFD drives it is essential to have correct earthing otherwise insulated bearings and brushes will not help.
In my option, it depends on the horsepower of the motor. The costs of motor under 60 hp doesn't not justify insulating either bearing. 75 hp (360 frames) to the end of t frames roughly 250 hp in a 4 pole, i would just insulating one bearing. Everything after t frames I would insulate both bearing if being used on a VFD. After 2000 hp I would insulate and add a shaft grounding ring for insurance. The level of protection must be weighted against how critical the motor is, and the costs of the protection versus the costs of replacement/time to reorder.
From:
Guest
|
Date:
05/06/2017
Was this review helpful?
Yes
No
(0/0)