If you have a typical iron core mains step-down isolating transformer with a resistive load connected to the secondary, do you get a voltage spike when the load is disconnected, or is the magnetic energy diverted back though the core to the primary creating a voltage spike on the mains side, or do you get a combination of voltage spikes on both sides, or nothing at all?
Likewise if the primary is suddenly disconnected does the remaining magnetic energy generate a voltage spike on the secondary?
I haven't seen any info about this on the web and I don't have any mains (240v) rated test equipment for measuring voltage spikes.
My particular application uses a 240v to 9v @ 10amps step down transformer.
Mike