Ferroresonant transformers and 3278

jwsmobile jws at jwsss.com
Thu Dec 31 05:05:09 CST 2015

On 12/30/2015 11:45 PM, Mike Ross wrote:
> Thanks for the thought... my main concern is the System/3s and Henk
> Stegeman - who has forgotten more than most of us will ever know about
> S/3! - says that 60Hz S/3 on 50Hz power is a no-go. Different voltage,
> fine - transformer can be restrapped. Different frequency... trouble!
> And then there are rotary machines of course. I bet you half my disks
> drives need the right frequency or a spindle pulley change.. and even
> then *they* probably have ferroresonants in their power...
> Mike
Order a boatload of 8kw honda generators?  I think you could get 40 amps 
out of them.  Any reason the power has to be in phase?

I know for the mainframe power that might not be high enough, but on 
smaller machines it would take care of the problem.

> On Thu, Dec 31, 2015 at 6:37 PM, William Donzelli <wdonzelli at gmail.com> wrote:
>> I bet you (or Mike, actually) could get it to work by trial and error,
>> swapping in caps. The transformers (generally) are apparently pretty
>> forgiving - being off in frequency just results in lost efficiency,
>> maybe 10-15 percent lost at most. Not flames, anyway.
>> --
>> Will
>> On Thu, Dec 31, 2015 at 12:30 AM, Guy Sotomayor <ggs at shiresoft.com> wrote:
>>> 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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