Ferroresonant transformers and 3278

William Donzelli wdonzelli at gmail.com
Mon Dec 21 20:45:26 CST 2015

In the long term, you should probably break down and get a good size
frequency converter.


On Mon, Dec 21, 2015 at 9:33 PM, Mike Ross <tmfdmike at gmail.com> wrote:
> I recently blew up a 3278... it worked ok for a few hours then started
> blowing fuses.
> 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.
> 1. Does anyone in a 50Hz country have any dead/spare 3278s and/or
> transformers for them? The IBM part number for the 50Hz 220V are
> 8715343 or 4119686.
> 2. I have other equipment where this will be an issue and not so
> easily solved. Does anyone have any experience in or recommendations
> for frequency conversion equipment? My System/3s for instance all use
> 60Hz ferroresonants operating off 208V 3-phase - now voltage can
> probably be retapped or easily converted but I still need to make a
> lot of 60Hz to run them...
> Thanks
> Mike
> http://www.corestore.org
> 'No greater love hath a man than he lay down his life for his brother.
> Not for millions, not for glory, not for fame.
> For one person, in the dark, where no one will ever know or see.'

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