On 24 Mar 2015 at 0:27, Neil wrote:

> Hi all,
>=20
> My high-school robotics team has this mill (=20
> http://www.amazon.com/Grizzly-G1006-Mill-Drill/dp/B0000DD0AF ) and the=20
> motor recently stopped.  If I switch it on repeatedly, every few times=20
> it will "kick" is smidge as if it wants to come on, but does not.
>=20
> It has 2 capacitors (run and start) and a centrifugal switch on the=20
> motor shaft with a switch.  And it runs on 110VAC.  I'm not sure what=20
> type of motor it is.
>=20
> So far, I've checked both capacitors (had them tested and they're fine),=
=20
> plus I've checked the centrifugal switch, cleaned the switch contacts=20
> and verified that the switch makes contact when the centrifugal switch=20
> is manually flipped outwards.  I've also gone through the junction box=20
> on the side of the motor, verified and tightened up all connections and=20
> tested the power switch to ensure that works fine.
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> I was thinking that if I can get another motor from elsewhere I could=20
> swap that in to verify that everything I've tested so far does indeed=20
> work properly, but so far I can't get a hold of another. According to=20
> the manufacturer, since all else checks out, it must be the motor, but=20
> before I have that shipped off, what else can I check or how can I test=20
> the motor directly?

Hi Neil,

Sounds like your typical AC induction motor with typical start problems. Ca=
n you=20
(with due care) spin the motor then it runs ok? Will be possible if just st=
art=20
winding/circuit is open circuit for some reason... though typcial symptom i=
s sitting=20
still and humming which is not exactly what you describe. There should be 2=
 x motor=20
windings, start & run, you could measure the resistance of each to make sur=
e=20
neither is open circuit. Centrifugal switch I would intuitively expect to b=
e the opposite=20
of what you say, ie. should be closed while starting so that start winding =
& cap are=20
in circuit (cap gives it the phase difference to ensure a rotating magnetic=
 field, drops=20
out at speed when no longer required).



--=20
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