[time-nuts] No more 60Hz! TEC Elimination

Will Matney xformer at citynet.net
Mon Jun 27 13:37:42 UTC 2011


Oz,

Some companies in the US are producing 50 hz transformers in their mass
produced units so they can readily sell them to the European market and
here. That is a plus for us, if we buy one, as they will run a lot cooler,
and last longer over it, when we apply 60 Hz to one. There's a bit more of
an amount of iron in a 50 Hz, which means for the applied line voltage, the
flux density will be lower, and thus, the whole thing will run cooler.
However, for a European, 50 Hz, transformer, you'll have a multiple
primary, if it's made to run here or there, as if I recall, their line
voltage is about double what ours is.

When I wrote most of the Wikibooks article on Transformer Design, I did a
major study on transformers, and probably now have 30+ books on the subject
alone. Some of the better information I read was written by Col. William T
McLyman, in his series of books on the design of transformers for NASA.
Another good book was written by engineers at MIT, and they still update
it, since it was written in the 1940's. From them, though, I learned a good
deal about their construction from wall-wart size, all they way up to the
huge oil-filled ones, now sitiing at our power stations. Plus, I used to
sell equipment to Kuhlman Electric, in Lexington, Ky., and another
transformer manufacturer in Cincinnati, Foster Transformer, and was privy
to how they built the things.

Best,

Will

*********** REPLY SEPARATOR  ***********

On 6/27/2011 at 6:44 AM Oz-in-DFW wrote:

>On 6/24/2011 9:20 PM, Will Matney wrote:
>> However, I should have
>> said, one should never run a 60 Hz transformer, or motor, on the same
line
>> voltage it was rated for at a lower 50 Hz.
>Most modern commodity transformers for electronic power supplies are
>specified for rated performance from 47 to 63 Hz.
>
>Most power distribution system products for use in the US I've seen are
>rated at 60 ± 3 Hz though some stuff from European manufacturers is
>rated at ± 2.5 Hz.  I guess it's a holdover from 50 Hz specs. 
>
>The power companies seem to spec normal variation at a max of 0.1 Hz
>though I understand the max offset they use by agreement for phase
>adjustment is about 0.02 Hz.
>
>A lot of large machinery has a a great deal of independence from the AC
>line frequency.  Even a 60 year old paper mill I did some work for had a
>mechanical phase adjustment driven by large DC motors on the machines in
>their line.  IIRC the controls guy said they could compensate for 1 Hz
>line frequency variations over 10 seconds. This was a lot faster than I
>expected.  Paper mills have lots of spinning mass that takes a long time
>to influence.
>
>Oz (in DFW)
>
>-- 
>mailto:oz at ozindfw.net    
>Oz
>POB 93167 
>Southlake, TX 76092 (Near DFW Airport) 
>
>
>
>
>
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