Hi, I am currently working on a project where we are require to purchase 4 units of 1600 kVA hermetically seal transformer. I come to a situation where a few of our vendors are proposing a hermetically seal type transformer that the tank top of the transformer is NOT welded, but instead it is bolted with gasket to prevent oxigen ingress.

Based on my limited experience on transformer, I always understand that hermetically seal transformer shall be welded, including the tank top. This is applicable to our transformer which is purchased 10 years back, where the tank top is welded.

However, these vendor had now reply that the due to the advancement of the gasket technology, they are confident to propose a bolted type. Would like to understand anyone could share their experience on this issue ??

Rgds,
AK