絶縁 ぜつえん変圧 へんあつ ではありませんでした
zetsuenhen'atsukidewārimasendeshita

Noun
Desu Copula

The polite, past negative form of 絶縁変圧器

1. Was not an isolating transformer.

Past/Perfective
Negative
Polite
Formal Register