Ferroresonant transformers and 3278

Guy Sotomayor ggs at shiresoft.com
Wed Dec 30 23:30:38 CST 2015

On 12/30/15 9:29 PM, William Donzelli wrote:
> Of course! Find the exception that proves the rule!

;-)  However, it would've been nice if it were only necessary to change
the capacitor!

TTFN - Guy
> --
> Will
> On Thu, Dec 31, 2015 at 12:23 AM, Guy Sotomayor <ggs at shiresoft.com> wrote:
>> 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
>> capacitor.
>> TTFN - Guy

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