FW: Salient Pole Motor

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Original poster: "Colin Dancer by way of Terry Fritz <twftesla-at-qwest-dot-net>" <CMD-at-dataconnection-dot-com>

Resend due to mail problems

-----Original Message-----
From: Colin Dancer 
Sent: 04 March 2002 11:47
To: 'Tesla list'
Subject: RE: Salient Pole Motor


<snip>
	The simplest way is just to assume it IS in sync because nothing
	can go wrong :-))
<snip>

If only it were that easy! 

My current score is:

	3 motors that just worked
	1 that worked with a 6" disk but not with the 7" I'd hoped to use
unless I ran it at 110% line voltage or doubled the size of the run cap
	1 that had a stator fault and which I should have tested before I
went to the effort of machining the rotor ;-)

Apart from a proper line locked strobe, the best tester is your ears.  An
altered but not quite locked motor makes a sound which is absolutely
unmistakably once you've heard it once.  The best I can describe it is a
".....wwwwWWWWW.....wwwwWWWWW.....wwwwWWWWW" sound with a period between
0.5s and 4s.

If you illuminate a motor in this state you see the rotor slowly lagging
(the hum getting louder and louder) and then slipping (when it goes quiet).


Bigger disks and higher drag speed up the slip rate.

If your motor isn't quite locked then a higher voltage from a variac will
sometimes help, as will an increase in size of the run capacitor.

Colin.