Ferroresonant transformers and 3278

William Donzelli wdonzelli at gmail.com
Wed Dec 30 23:06:48 CST 2015

Sorry about digging up a slightly stale thread...

> I haven't done any troubleshooting yet but checking the manuals on
> Bitsavers tells me my US 3278s have ferroresonant transformers
> specified as 120V 60Hz only. This can be expected to cause problems
> with 120V 50Hz here in NZ from my knowledge of how ferroresonant
> transformers work; I'll get excessive magnetic currents - overheating
> - all kinds of nasties. I can wind the voltage down a bit and run them
> at 90-100V but that doesn't help much.

...but straight from the horses mouth, most IBM ferroresonant
transformers will work at 50 or 60 Hz. The capacitor may need to be
swapped, depending on the equipment.

I was hanging around some IBM old timers this evening, including the
Big Horse at Endicott.


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