Questions...
Well, thanks for the interest but I am not at all an expert in either AC motors nor in ZV switching. If I knew these answers I would not have posted my question. I am talking here of a small fan motor (NMB brand, marked as impedance protected), not an industrial blower - my guess is that it could be slowed to half without overheating, and that triggering the triac with a ZVS would work and keep down the electrical noise. Possibly some simple way to trigger the ZVS on every other full cycle? The fan did not seem to overheat when I controlled the triac with a diac and phase control circuit, though I did not run it very long, really. Anyway, I'm pretty resigned to finding my 120mm DC fan and an appropriate wall wart this weekend. But if anyone knows an answer to my dilemma in the meantime I'd like to hear it. - kenne