Ferroresonant transformers and 3278

[William Donzelli]

If you can get a rotary one, those are really nice - just wasteful and
loud. With proper maintenance they last forever, can take a beating,
and do not give waveshape issues that cheap solid state units can
have. And, maybe most importantly, you can make one yourself.

But considering the mix of 50 and 60 Hz stuff you likely have by now
(that is what you get for moving!), spending some decent money on a
real VFD might be worth it. I might think a cheap VFD may give
ferroresonant iron fits with all those extra harmonics.

--
Will

On Mon, Dec 21, 2015 at 9:48 PM, Mike Ross <tmfdmike at gmail.com> wrote:
> Any recommendations for what type? Are solid-state devices up to the
> job these days? I still remember rotary converters...
>
> Mike
>
> On Tue, Dec 22, 2015 at 3:45 PM, William Donzelli <wdonzelli at gmail.com> wrote:
>> In the long term, you should probably break down and get a good size
>> frequency converter.
>>
>> --
>> Will
>>
>> 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.'
>
>
>
> --
>
> 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.'