Ferroresonant transformers and 3278

Guy Sotomayor ggs at shiresoft.com
Wed Dec 30 23:23:13 CST 2015

On 12/30/15 9:06 PM, William Donzelli wrote:
> 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.

I just looked up the FE manual for the 3278 and it shows 5 different 
part numbers for the
ferroresonant transformer (depending upon region) and only a single part 
number for the

TTFN - Guy

More information about the cctalk mailing list