Hal, The speed differences below are for a two and four pole motor.
Two Pole: 50 Hz: 3,000, 60 Hz: 3,600 Four Pole: 50 Hz: 1,500, 60 Hz:1,800 Those are not loaded speeds, however, 1800 / 1500 = 1.2 I mis-stated that post, it should have been 1.2 times greater than, or less than, the speed, but it's around 17%, I think, (17% of 1800 is 306 RPM). Thanks for catching that. I didn't see the graph, but in the case of 59.95 Hz, it wouldn't faze working motors or transformers enough to harm them, I would think. It would motors for clocks though, over a long time span. Thanks, Will *********** REPLY SEPARATOR *********** On 6/24/2011 at 7:13 PM Hal Murray wrote: >> Clocks is not what I'm concerned over as much as certain pieces of >> industrial equipment that must rotate at a certain speed, or are supposed >> to. Also, if they are going to allow the frequency to get slower, any motor, >> or transformer, needs more iron in it, and just a 10 Hz difference is enough >> to amount to a significant increase in iron. One can easily use a 50 Hz >> transformer on 60 Hz, but not a 60 Hz on 50 Hz. The speed difference in >> motors from 50 Hz to 60 Hz would be around 1.2%, just roughly guessing it in >> my head, at 1800 RPM, and we don't know how much they intend to allow it to >> vary. > >I think you are missing the decimal point. > >How do you get 1.2% from 50 to 60 Hz? I get 16%. > >The graph had events under 59.95 Hz. That's roughly 0.1%. > http://tinyurl.com/6ytqsx7 > http://www.nerc.com/page.php?cid=6|386 > > > > >-- >These are my opinions, not necessarily my employer's. I hate spam. > > > > >__________ Information from ESET Smart Security, version of virus signature database 5851 (20110206) __________ > >The message was checked by ESET Smart Security. > >http://www.eset.com _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
