On Sunday 13 December 2015 13:27:53 John Kasunich wrote: > Did you ever try running the contactor on the original 120VAC to see > if the hum is actually a problem? > > Many AC contactors and relays have a shorted turn around a portion > of the core. The current induced in that turn causes phase lag in > that portion of the core, so between the two halves the magnetic flux > never goes to zero and hum is dramatically reduced.... > True, and these have a shorted turn around about 1/3rd of the outside leg of the E core tips. And its something I haven't checked yet. But the shop has enough "hum" polution as it is. Eventually you just can't tune it out and it becomes distracting. Particularly when the hum turns in to a buzzy rattle. These coils are not shimmed to be motion restricted so the coil itself can potentially buzz all by itself.
I am running out of time today, but for that I'll have to test all 3, and perhaps use the quietest pair. > Seems like a lot of effort to re-design things for DC operation. > > > John Kasunich > [email protected] > > ---------------------------------------------------------------------- >-------- _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Some mill pix are at: Genes Web page <http://geneslinuxbox.net:6309/gene/GO704-pix> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
