Hallo.
yesterday i got a 1/2 hp, 2780 rpm capacitor run motor - you can see
some pics of it here - http://himplast.ru/father_dest/temp/370w/
this puppy has no "dead poles" at all, and was fully rewound by hands
of some drunk electrician % )))
i see that nobody on the list really know, how deep should one shave
that poor rotor down to perform so called "salient pole" conversion.
i mean nobody know any formulas, nobody can explain how wide exactly
should one cut that flats, nobody know how one could verify that
performed conversion was optimal in terms of lost torque and etc.
am i correct on this?
coz all that i can find in archives is something blurry like this:
"The info I supplied is more of a general guideline than anything --
you will inevitably see variations on the number of poles, etc."
"Maybe the flats should still be 3/4" wide like the 1750rpm motor, I
don't know. There are various opinions."
"In other 3600 rpm cases I made the flats narrower, but the motors
seemed weaker. But these were all different motors so it's hard to
judge."
does anybody know any real physics that stands behind all of this? what
should one monitor in process - input currents, any phase shifts,
something else?
or coilers prefer just to cut 1/3 of od and don`t want to know nothing
more? : )
p.s.
"If the cuts on the armature are sufficient, the motor will lock into
salient-pole mode at roughly 75 to 85% of full voltage."
i like this particular criterion, but what if the input current at 75%
would be 2 times (for example) more than at 90%? or say torque would
be 2 times smaller? then i`ll better go for 90% i think.
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Let the bass kick! =:-D