# Delta contractor saw motor humming but not running



## Jeff Shafer (Nov 16, 2010)

Hi all, so I went down today to get some work done, and after some set up went to turn on the saw and the motor hummed but would not run. So I disconnected power and the drive belt, spun the blade which moved freely, spun the motor shaft which moved freely. Then with out the belt connected flipped the power switch and again the motor hummed but wouldn't run. Seems like I'm not getting enough power to run the motor. Any advice would be greatly appreciated?! :blink:


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## TomC (Oct 27, 2008)

Jeff Shafer said:


> Hi all, so I went down today to get some work done, and after some set up went to turn on the saw and the motor hummed but would not run. So I disconnected power and the drive belt, spun the blade which moved freely, spun the motor shaft which moved freely. Then with out the belt connected flipped the power switch and again the motor hummed but wouldn't run. Seems like I'm not getting enough power to run the motor. Any advice would be greatly appreciated?! :blink:


Sounds like the capacitor. I would try replacing it. I just had to do the same for my A/C unit. A total cost of less than$11.
Tom


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## Leo G (Oct 16, 2006)

Could be the capacitor or the startup windings switch which is internal to the motor. Did you blow everything out with air?


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## Steve Neul (Sep 2, 2011)

If the saw is 220v I would first check to see if both legs of power at the motor were hot. If so I would blow the motor out and if that didn't help then change the capacitor.


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## cabinetman (Jul 5, 2007)

You may have two capacitors...one for "start", and one for "run". If you have a multi-meter you may be able to check them yourself.



















.


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## knotscott (Nov 8, 2007)

A bad cap is a likely cause, but it could also a stuck centrifugal switch. If the caps both check out to be good, try spraying some WD-40 in the back of the motor, tapping on the back, and possibly gently probing with a screw driver to free it (it works a bit like a friction clutch and is usually located on the shaft at opposite end of the drive pulley).


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## GeorgeC (Jul 30, 2008)

I know of no way to check a capacitor with a standard multi-meter. How is that done?

George


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## cabinetman (Jul 5, 2007)

GeorgeC said:


> I know of no way to check a capacitor with a standard multi-meter. How is that done?
> 
> George


http://www.ehow.com/how_8523137_check-capacitor-multimeter.html
.
http://www.squidoo.com/how-to-check-capacitor



















.


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## Jeff Shafer (Nov 16, 2010)

Thanks all, I'll try all of the above suggestions!


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## TomC (Oct 27, 2008)

cabinetman said:


> http://www.ehow.com/how_8523137_check-capacitor-multimeter.html
> .
> http://www.squidoo.com/how-to-check-capacitor
> 
> ...


This works. However, it is easier to see with an analog meter. I did test my A/C capacitor with a digital meter and it was fairly easy to tell it was open.
Tom


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## GeorgeC (Jul 30, 2008)

cabinetman said:


> http://www.ehow.com/how_8523137_check-capacitor-multimeter.html
> .
> http://www.squidoo.com/how-to-check-capacitor
> 
> ...


All that will tell you is the voltage or resistance of a capacitor that is OUT of the circuit.

It does not tell you is the capacitor is is storing at it's rated capacity. There are high end (read expensive) meters that will read in farads.

George


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## TomC (Oct 27, 2008)

GeorgeC said:


> All that will tell you is the voltage or resistance of a capacitor that is OUT of the circuit.
> 
> It does not tell you is the capacitor is is storing at it's rated capacity. There are high end (read expensive) meters that will read in farads.
> 
> George


I t will tell you right quick if the capacitor will not take a charge or is shorted. 
Tom


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## GeorgeC (Jul 30, 2008)

TomC said:


> I t will tell you right quick if the capacitor will not take a charge or is shorted.
> Tom


Yes, but that is all that it will do. It will not tell you if the capacitor is "good." That is it will not tell if the capacitor holds the correct charge.

George


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## Jeff Shafer (Nov 16, 2010)

So it turns out the start capacitor is shorted out and the original has 2 screw connectors on top, and the wires coming out of the motor have eyelets for the screws to go through. So on Grainger I can only find capacitors with the correct micro farad rating with 4 quick connect terminals on them. I'm sure I could make one of these work but if there is a better source where I could find a unit with 2 threaded terminals that would be great!! It's always something?


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## woodnthings (Jan 24, 2009)

*try EBay*

http://www.ebay.com/sch/i.html?_trk...0&_nkw=starting+capacitors&_sacat=0&_from=R40


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## Tman1 (Jan 14, 2013)

Jeff Shafer said:


> So it turns out the start capacitor is shorted out and the original has 2 screw connectors on top, and the wires coming out of the motor have eyelets for the screws to go through. So on Grainger I can only find capacitors with the correct micro farad rating with 4 quick connect terminals on them. I'm sure I could make one of these work but if there is a better source where I could find a unit with 2 threaded terminals that would be great!! It's always something?


Per George's comment earlier, did you verify that it was shorted after disconnecting it from the motor? I assume you probably did. But, just wanted to make sure, because if it was still connected to the motor, it could appear shorted, even if it is not. 

Also, on the quick connect terminals, you can buy a handful and a crimper for them for a few dollars ( it's been a while since I bought mine, so I can't give a number) from most home stores or electronics stores, or even from Grainger when you order the cap.


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## Leo G (Oct 16, 2006)

If the capacitor was shorted out you would absolutely know. When you powered it up it would either blow up or trip the breaker.


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## Jeff Shafer (Nov 16, 2010)

So I got a start cap from Grainger that matches mfd, voltage and Hz rating of the shorted unit but it's got quick connect tabs instead of the screw mounts. Can I just get the female ends and connect them to the wires?


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## Leo G (Oct 16, 2006)

yes 
.......


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## Jeff Shafer (Nov 16, 2010)

New start capacitor did the job! Just a few more cuts then final assembly.


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## Leo G (Oct 16, 2006)

Way to go.


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## knotscott (Nov 8, 2007)

Good to hear...thanks for the update.


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