# Motor Starting Issues



## Latheman (Oct 1, 2015)

When I turn the lathe on the motor just hums. If I spin the pully it takes off just fine and runs fine until I shut it off and have to start again. It's a craftsman 1/3 hp 110. Should I replace the motor or is there a way to fix the way it starts? It doesn't matter if there is tension on the belts or not. Just won't start turning on it's own. A quick spin of the hand and it's off to the races. It does bother me a bit. All I want to do is turn on the switch and work. I can't say I like playing wheel of fortune when I machine. Any suggestions welcome. Thanks.


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## roadie33 (Oct 1, 2015)

Sounds like the start cap may be bad.


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## JimDawson (Oct 1, 2015)

roadie33 said:


> Sounds like the start cap may be bad.



Or the centrifugal switch is stuck open


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## RJSakowski (Oct 1, 2015)

Or an open start winding or a bad connection.  

It should be fairly easy to troubleshoot with an ohmmeter or continuity tester. One place to start would be to check the integrity of any spade connectors.  They can loosen up with time and once the connection starts to fail, it can self destruct fairly quickly.  If you have a reversing switch, all the wires leading to the reversing switch are suspect as well.

Bob


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## ericc (Oct 1, 2015)

Check to see if your motor has a capacitor.  It is often a lump on the side.  On the motor for my tiny lathe, there is no capacitor.  It uses a centrifugal switch and a start winding.


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## Latheman (Oct 1, 2015)

RJ. It does not reverse.  Ericc if it does have a capacitor, what then?


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## Latheman (Oct 1, 2015)

Dunlap (Craftsman) Motor 1/3 HP, SplitPhase, Volt 115, Amp 5.4, RPM 1750, CW-CCW This is exactly what it is.


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## Black13 (Oct 1, 2015)

Latheman said:


> RJ. It does not reverse.  Ericc if it does have a capacitor, what then?



Latheman I sent you a message with a link for troubleshooting split phase motors. If the capacitor is bad, you can swap it out in less than ten minutes. The cap should be marked with it's capacitance value. 
A quick Google search should find you a replacement in no time


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## VSAncona (Oct 1, 2015)

Many of the Craftsman motors have a flat capacitor that is housed in the base of the motor. Finding a replacement that will fit in the same space is often a challenge.


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## JR49 (Oct 1, 2015)

Black13 said:


> Latheman I sent you a message with a link for troubleshooting split phase motors. If the capacitor is bad, you can swap it out in less than ten minutes. The cap should be marked with it's capacitance value.
> A quick Google search should find you a replacement in no time


         Hey, Black13, how about posting that link here rather than in a PM, so that EVERYONE, not just Latheman, can benifit from it.  Thanks,  JR49


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## wa5cab (Oct 1, 2015)

Most capacitor start motors made since about 1950 (and many made earlier) have the start capacitor mounted under a cover on the outside of the motor body.  The start capacitor in this case is usually cylindrical,  And you can tell at a glance that the motor is a Capacitor Start type.  Some motors made earlier (and a few made since) have a rectangular start capacitor hidden in the base casting.  These you have to look more closely to ID.  However, if the nameplate on the motor says "Split Phase" as I assume from your most recent post it does, then there is no start capacitor.

That being the case, and given that the motor worked for a while and suddenly quit starting on its own but does run if you start it manually, the most likely culprit is that the centrifugal switch (which opens to disconnect the start winding after the motor starts and gets up above about half speed) is stuck in the open position or much less likely, the switch contacts are burned.  Less likely is that one of the connections to the start winding was loose or corroded and suddenly went open.  However, I would probably unplug the line cord and wiggle any spade connectors, loosen and then tighten any electrical contact screws, and tighten any wire nuts first.  And then try the motor.

If that doesn't fix it, then you should unplug the motor, remove it from the lathe, and carefully remove the bearing carrier casting from the field housing on eht end of the motor containing the wiring and check the centrifugal switch.  As there are many types, I can't describe exactly what it will look like   But the rotating part will be mounted on the armature shaft and the switch itself on the bearing carrier casting.  Be aware that jiggling things while removing the casting may unstick the centrifugal weights.  Lubricate the obvious points with a very little oil and if possible manually cycle the weights and the switch and then put it back together and try it.


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## Black13 (Oct 1, 2015)

JR49,
Not sure if the link would go against the copyright rules of the forum or not. I'll check up on it and post it here if it's ok.


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## wa5cab (Oct 1, 2015)

It's OK to post such a link unless the destination says otherwise.


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## Black13 (Oct 1, 2015)

Thanks for the quick reply "wa5cab".

http://www.fluke.com/fluke/uses/com...s-drives-pumps-compressors/single-phasemotors


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## Latheman (Oct 1, 2015)

http://www.woodworkingtalk.com/f12/repair-your-bandsaw-other-motor-crash-course-46405/ also found this link if helpful. I love your link too Black13.


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