Al didn't say you had a "short". He said you had an "open". They are opposites of each other. He only mentioned "shorted turns" to imply that they are NOT likely to be the problem.
A broken wire is an "open", resulting in zero current. A "short" is two wires touching each other, causing the current to take a shorter path than intended. In a lamp cord a short would blow a fuse, whereas an "open" would prevent current from flowing. I recommend not saying "short" when you mean "open" (though many electrical novices do). If you said you thought "the motor has a short" at a repair shop, it would mark you as unknowledgeable, maybe setting yourself up to be ripped off. The symptom of an "open" in your motor would be that nothing happens at all. On the other hand, saying the motor has a short (or more specifically "shorted turns") means that a few of the loops of wire in the coils are shorted together, causing the current to bypass them. This would lower the overall resistance of the coils, thus increasing the current. The motor would still run, but would have less magnetic torque (because some of the turns of wire are not carrying current), and the remaining turns would get hot. Sorry for the lecture, but as an electrical engineer, this is one of my pet peeves. Jim On Feb 15, 2013, at 8:53 AM, Vinyl Visions <vinyl.visi...@live.com> wrote: > Al,Thanks for the reply. As you noted, I have been advised that it was a > short in the motor somewhere. The problem seems to be that this motor is > wound for three different types of power - AC/DC and maybe 220. So, either > the shops don't know what the problem is or they just don't want to mess with > it... I'm tending toward the latter, since the guys I sent it to are very > knowledgeable. There is a picture of the motor on our website: > www.carolinaphonosociety.com > A shortcut to the pic is: > http://open1234.wix.com/camps-site/twilight-zone-2#!__fairy-phono-lampCurt > >> To: phono-l@oldcrank.org >> From: clockworkh...@aol.com >> Date: Fri, 15 Feb 2013 04:01:17 -0500 >> Subject: Re: [Phono-L] Turntable Motor Question >> >> >> Induction motors that lack torque can usually be traced to an open field >> coil or an open armature loop. A shorted turn will eat torque but the motor >> will let you know by getting hot. How about a photo of the motor? Most >> good motor shops can fix anything from fractional horsepower to 100 HP. >> Do you know of a fan collector in your area? I have repaired fan motors >> that lost power and have the same symptoms of your phonograph. These things >> are not rocket science. >> >> Best wishes, >> Al _______________________________________________ Phono-L mailing list http://phono-l.org
