Internal Fusing of Transformer

[sech]

I have a project that requires a 12.470-4160 5000KVA cast Coil Transformer with internal oil immersed fuses. I have quotes from manufacturers that took exception to that spec, stating that they do not have internal fusing at that rating (5000 KVA)and 2500KVA is the largest KVA with internal fusing. This transfomer is within 500 feet of the MVS with RBA-400 fuses. Why would the designer want internal fusing so close to the primary? Does any manufacturer have internal fuses for 5000 KVA transformers?

 

[davidbeach]

I've never seen internal fuses on a cast coil transformer, and you certainly wouldn't have oil immersed fuses on a cast core transformer. Somebody needs to understand the equipment being specified and know what works together and what doesn't.

 

[jraef]

Sounds to me as though some engineer took it upon himself to blend specs, then ended up with something that nobody makes. That unfortunately happens quite a bit. One of the big benefits of spending the extra for a cast coil XFMR is to not have the oil!