On Sunday 14 June 2015 09:49:33 Kirk Wallace wrote: > On 06/14/2015 04:48 AM, Steve Stallings wrote: > >> -----Original Message----- > >> From: Gregg Eshelman [mailto:[email protected]] > >> Sent: Sunday, June 14, 2015 4:12 AM > > > > <snip> > > > >> If it has a 240 option on both primary and secondary, would not > >> using the 240 taps on both make it a 1:1 so putting 120 in would > >> get 120 out? > > > > Yes the voltage ration will hold. You can even swap the > > secondary and primary sides but there may be differences > > of a few percent because the listed voltages include a > > margin for internal losses. > > > > What you cannot safely do is exceed the current rating > > of any winding even though the total power is within > > specifications. This is because excess current can > > saturate the magnetic core which can result in suddenly > > lower impedance and bad things will happen. > > > > In the example that you gave, this would mean that you > > would only be able to safely get half as much power from > > the transformer. > > Hmmm, I'm wondering if this could be checked easily. Clamp -on > ammeters are cheap, maybe check the current going in, then compare the > current going out. At some point the input will start to get much > higher than the output.
It will do that very quickly in ferrite, such as a toroid, because that saturation point is often mirrored to the curie point, and when Ferrite goes non-magnetic due to core temps exceeding the curie point, its wrecked, magnetic impedance lost. The next thing is the invertor transistors, which usually fail about 100 milliseconds before a fast blow fuse can clear. > > Temperature might be a indicator too. > > (https://en.wikipedia.org/wiki/Saturation_%28magnetic%29) 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) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
