HT (High Tension or High voltage) motor's shaft and our 300mw Alternator's exciter bearing are being grounded. Why they are grounded? plz explain a bit.. i also heard the ground is not solid but via a "capacitor" or so..Why its so..

{if some one have some pdf plz send at [email protected])

 

Dear santan,

i studied resistive grounding, inductive grounding, and solid grounding,
But I have not studied capacitor grounding.

If you have any material on capacitive grounding, please send to me for study.

 

Dear Sir,

Due to rotation, in influence of magnetic field, what so every small in intensity (sometimes due to even statics charge), there always will be some shaft voltage. Now if, end bearing is not insulated, the shaft will be 'Earthed' from front bearing carbon brush and un-insulated rear bearing. The circuit will be like a battery, and eventually end-up in damaging the bearings.

I request Mr. CSA to explain more in details about how hydrodynamic oil film behaves as an insulator and why GT bearing 3 is more effected more.