Trnasformer Question

[dannay]

transformer is a 4160v pri with a 208/120v secondary and the specification reads to have a 'BASIC IMPULSE INSULATION LEVEL: 75kV' however, the supplier wants to lower the level to 60kV

This is over my head and I'm just wondering if anybody can tell me the difference and/or impact on the performance of the transformer?

 

[rcwilson]

Re: Trnasformer Question

30kv, 45 kV, & 60 kV are typical BIL levels for 5 kV class dry type transformers. 75 kV BIL is not a standard rating. 30 kV is listed as the "standard", 45 & 60 kV are optional enhanced levels. The specification may have a typo or there may be a good reason to require the higher impulse voltage level for this application.

BIL represents the ability of the transformer to withstand a sudden voltage surge, like a lightning strike or surges from a large VFD.

Another way to add surge voltage protection without increasing the BIL is to select surge arrestors for the transformer to mitigate any high voltage surges above the transformer withstand level. This allows the use of a "standard" BIL level when high surge voltages are expected on the system.

 

[dannay]

Re: Trnasformer Question

RCWILSON...you just made my day, thank you very much!!