Safe series secondaries...sane, sacreligious, stupid??

[guest]

If I use these three 9KV tar potted transformers I've aquired with the three secondaries wired in series I'll run the risk of breakdown to the cases or the primaries as the HV climbs won't I?.

There's no secondary connection to the metal case as a neon sign transformer has and the outputs come out on 4 inch porcelain insulators. Will it lessen the risk of breakdown to the case if I mount the transformers on an insulating base and then power them off a 2KVA isolation transformer and 2KVA variac all mounted together inside an earthed cabinet?.

If this approach is on a par with trying to float a neon tranny or gang up some microwave transformers I would welcome being told so, the other alternative would be to parallell the secondaries and triple the voltage with all it's attendant hazards.

[Richard Hull]

If you truly have no secondary connection to the case, series connecting the transformers becomes a possibility provided, as you note, the trasformers are mounted well insulated from each other.

There is some probability of primary break over, but it is more likely only if you arc or spark the secondaries which would be more likely to stress the insulation.

Only assembly and testing would settle the issue.

Richard Hull