Older table saw motor stalling

[brad hays]

Just got this 30 year old Craftsman table saw for free because the motor's not spinning, 1HP 110v. Before sourcing another I'm curious if I can get this one working again. When you hit the power the motor makes a decent hum and sounds like it's trying to go. Also there's an quick intermittent screeching that I'm guessing is a bad bearing. If you take the belt off and spin the pulley it gets up to speed fairly quickly making no unusual sounds or vibration. The notched arbor protrudes from the opposite side as well and I get the idea I could kick start it with a drill if I could hack together some kind of adapter.


If I can do say a $20 dollar repair I'd rather do that as opposed to $80+ for a replacement. Any idea what's gone wrong with this poor old motor?

450836

450837

[Bill Bukovec]

Sounds like the centrifugal start switch inside the motor is not closed. Try wacking the motor with a hunk of wood when you first turn it on to get the switch to close.

Next, take the motor apart to see if the switch contacts are corroded or packed with sawdust.

[Lee Schierer]

Most likely the start capacitor under that black sheet metal lump is bad. Replace it with a new one and your saw should run.

It appears that there is a little yellow plug right under that red thermal reset switch and it is likely there is a second one on the other end of the motor. Pop those two plugs out and add a few drops of light oil down the holes. That will lube the oil lite shaft bearings. wait a day or two after adding the oil before running the motor. Then make a note to oil them about once a year or more often if is used every day.

[brad hays]

Thanks for the advice. Turns out it's the capacitor but I think it'd be wise to get the motor open and do some servicing as it's so old and filled with dust. I don't have any experience with working on these motors but I understand generally how they work. What should I do inside the motor besides cleaning contacts?

And I was glad to get your advice Lee on oiling the motor plugs but after getting the sawdust off I don't think this motor has the kind of plugs you mentioned. I see what you were suspecting though.

It is indeed my capacitor as it makes the concerning hum and blows the house breaker just like the repair video illustrated. I've searched for some of the numbers on the side here but haven't come up with anything yet. Wonder if ebay or amazon has them.

It says MALLORY just above the text

450844

[Ron Selzer]

Thanks for the advice. Turns out it's the capacitor but I think it'd be wise to get the motor open and do some servicing as it's so old and filled with dust. I don't have any experience with working on these motors but I understand generally how they work. What should I do inside the motor besides cleaning contacts?

And I was glad to get your advice Lee on oiling the motor plugs but after getting the sawdust off I don't think this motor has the kind of plugs you mentioned. I see what you were suspecting though.

It is indeed my capacitor as it makes the concerning hum and blows the house breaker just like the repair video illustrated. I've searched for some of the numbers on the side here but haven't come up with anything yet. Wonder if ebay or amazon has them.

It says MALLORY just above the text

450844

you want to be close or a little over on mfd rating, voltage rating needs to match or be over(can be a lot over, just not under)

ebay https://www.amazon.com/Motor-Start-Capacitor-270-324-220-250VAC/dp/B00CLJFZN0/ref=sr_1_16?dchild=1&keywords=255+mfd+start+capacitor&qid=1612057852&sr=8-16
https://www.ebay.com/itm/216-259-MFD-110-125-vac-Electric-Motor-Start-Capacitor-uf-HVAC-volts/401963477382?hash=item5d96e3e986:g:rxoAAOSwM0hd0zz b
https://www.ebay.com/itm/PMJ233-233-280-uf-mfd-110-125-Volts-Start-Capacitor-NEW/151843686097?epid=710127993&hash=item235a96c6d1:g:rK8AAOSwURhdoH6q

amazon https://www.amazon.com/dp/B00CLJFZN0/ref=nav_timeline_asin?_encoding=UTF8&psc=1

Ron

[Bill Dufour]

215-265 MFD is the capacity of the capacitor so anything in that zone will work. 110 volt rating is low and why it failed. It should be at least 169 volts unless it states RMS volts then 120 is okay. It is not polarized so do not worry about which wire goes where. Should cost under $10.00 from ebay
Bil lD

[Rod Sheridan]

Thanks for the advice. Turns out it's the capacitor but I think it'd be wise to get the motor open and do some servicing as it's so old and filled with dust. I don't have any experience with working on these motors but I understand generally how they work. What should I do inside the motor besides cleaning contacts?

And I was glad to get your advice Lee on oiling the motor plugs but after getting the sawdust off I don't think this motor has the kind of plugs you mentioned. I see what you were suspecting though.

It is indeed my capacitor as it makes the concerning hum and blows the house breaker just like the repair video illustrated. I've searched for some of the numbers on the side here but haven't come up with anything yet. Wonder if ebay or amazon has them.

It says MALLORY just above the text

450844

Hi, don’t take the motor apart there’s a reason to do it.

As others have said, oil it (not too much), blow out the dust, replace the capacitor and you should be good.....Regards, Rod

[Andrew Seemann]

I have a similar motor on my old 9" Craftsman table saw. The old man put it on some time in the early 70's. It will do OK in pine and most hardwoods up to around 3/4". It didn't like 7/8" white oak.

If it is an easy fix, I would consider it, but I wouldn't put a lot of time and effort into a motor that is at least 30 (more likely 40+) years old that was originally average at best. If you have to swap it out, look to see if a 1 1/2 HP will fit the saw.

[brad hays]

Well, lesson learned is if it walks like a bad capacitor and talks like a bad capacitor, it very well could be a bad centrifugal start switch...and that's what it turned out to be. After getting the new cap in it did the same growl no start and after getting it all apart and cleaning the switch it starts like a dream. Well almost, I have a replacement bearing on the way but after that this 30+ year old motor should run like new. Thanks for all the direction guys.