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Re: 60hz on a 50hz machine
Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>
Tesla list wrote:
> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> what would happen if i were to put 60 hertz on 50 hertz transformer?
I can relate a personal experience. Back in 1946 I worked at Naval
Research Laboratory in the Washington, DC area and built a TV set for
amusement. I got the transformer shop at the lab to build me a very
efficient transformer to provide 4000 VAC for the CRT circuit, and 600
VAC for the rest of the receiver. (Those were tube days, of course, and
the AC was rectified.) Anyhow, I moved to Altadena, California in the
summer of 1947 and unpacked my TV set and turned it on. Unbeknownst to
be, Edison Company power at that time was 50 Hz. Bottom line is that
after a few hours the transformer got so hot it fried its little self.
This particular transformer used a 1 mil Hypersil core and, in spite of
the fact that the losses were very low on 60 Hz, apparently ran pretty
close to core saturation. (Designer didn't waste any extra wire,
transformer ran quite cool on 60 Hz.) Apparently the increase in core
flux density was enough to it into saturation, with disasterous results.
I think this is an extreme example of running a device on a lower
frequency than that for which it was designed, or at a higher voltage at
the design frequency. Running a 50 Hz motor on 60 Hz would result in a
higher speed, but also reduced torque unless the voltage were
increased. The motor could take (60/50) as much voltage without
increase in core saturation.