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Drill Press Starting Capacitor

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Blog entry by bosum3919 posted 07-22-2015 04:09 PM 1847 reads 0 times favorited 11 comments Add to Favorites Watch

I have an old Craftsman 2/3 HP drill press that I have been using for years and it suits my purpose for many small tasks. Recently, the starting capacitor went out. I can still start the press by hand, but the capacitor won’t carry the load to start it. All of the pertinent information is printed on the capacitor, so I orderd one through Amazon. I have had the same problem with ceiling fans and have replaced the capacitors from there as well. The problem arises in that it seems that all capacitors are now made in China and are of questionable quality and reliability. The new one from Amazon does not give any better results that the one I replaced. It won’t start the motor either. Therefore, the question is have others had this same problem with starting capacitors and how have you resolved it? Is there a reliable source of starting capacitors that I am not aware of?

-- Bob



11 comments so far

View dschlic1's profile

dschlic1

330 posts in 1433 days


#1 posted 07-22-2015 04:58 PM

There is a switch located at the rear of the motor. This switch operates on the speed of the motor. When the motor is stopped or is accelerating it is closed and connects the capacitor to the motor. Once the motor is up to speed, it opens and disconnects the capacitor. Perhaps this switch is open/bad.

View bosum3919's profile

bosum3919

338 posts in 1082 days


#2 posted 07-22-2015 08:25 PM



There is a switch located at the rear of the motor. This switch operates on the speed of the motor. When the motor is stopped or is accelerating it is closed and connects the capacitor to the motor. Once the motor is up to speed, it opens and disconnects the capacitor. Perhaps this switch is open/bad.

- dschlic1

Thanks. I appreciate the information. I will check for the switch tonight.

-- Bob

View greg48's profile

greg48

588 posts in 2221 days


#3 posted 07-23-2015 08:07 PM

I’ve experienced similar problems on my TS and ShopSmith. Took the motors down to the local motor shop expecting to be paying for an expensive repair or worse. He opened up the capacitor housing, blew out the accumulation of dust and debris, connected them to a power source and they spun right up. No charge, come again (I will).

-- Greg, No. Cal. - "Gaudete in Domino Semper"

View bosum3919's profile

bosum3919

338 posts in 1082 days


#4 posted 07-24-2015 02:46 AM

Based on the information provided above by dschil1 I have done some extensive reading and study. Have you ever heard the term “I know enough to be dangerous” ? Well, I am feeling dangerous. I have determined that the switch in question is correctly named a centrifugal switch. This switch basically operates similar to the way points used to work on cars. I now, in theory, know how to test for a defect, adjust misalignment and or replace the switch. Tomorrow, I will be opening the hood, so to speak, and applying this knowledge. Stay tuned as I will update the progress and or lack thereof.

-- Bob

View bosum3919's profile

bosum3919

338 posts in 1082 days


#5 posted 07-24-2015 02:50 AM



I ve experienced similar problems on my TS and ShopSmith. Took the motors down to the local motor shop expecting to be paying for an expensive repair or worse. He opened up the capacitor housing, blew out the accumulation of dust and debris, connected them to a power source and they spun right up. No charge, come again (I will).

- greg48

Greg, based on the info I have gathered, your description of blowing the dust out is the lucky version of what my problem may be. I hope my fix is that simple. However, Murphy may have his say in the problem.

-- Bob

View dschlic1's profile

dschlic1

330 posts in 1433 days


#6 posted 07-24-2015 04:55 PM

I suggest that you do your testing without power. If you don’t have an ohm meter (DVM) I suggest that you get one. HF have some for little$. Lacking that, open the motor with power removed, take some fine sandpaper (220 or 320) and sand the two contacts on the switch. Also inspect that the two contact are touching each other. You can sometimes operate the switch with the motor off by moving the “wings” on the armature (the rotating part). At this point you really do not have anything to loose.

View bosum3919's profile

bosum3919

338 posts in 1082 days


#7 posted 07-25-2015 12:16 AM

Dschlic1 thanks for all of the excellent advice. I took the motor apart today and the points on the centrifugal switch were locked open as you suggested. They were also pitted with a carbon build up. Took everything apart, cleaned and sanded. Took the air compressor to the whole thing. Collected parts numbers, then put it back together. Held my breath and flipped the switch. IT WORKS.

Not sure how long it will hold up, so I have started the search for a new switch. Murphy’s law is at work again. I can find all kinds of switches except mine. However, I am persistent so I will keep looking. If anyone knows where I can find part number LG17-154Y, it would sure make my day

-- Bob

View TheFridge's profile

TheFridge

5765 posts in 949 days


#8 posted 07-25-2015 12:35 AM

The problem prob has more to do with dust and junk getting between the contacts. If the switch is mechanically functioning properly and the contacts are clean, there is very little arcing. Throw enough dust in there and it’ll cook.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View changeoffocus's profile

changeoffocus

457 posts in 1080 days


#9 posted 07-27-2015 10:28 PM

Informative series of replies and feed back. Thanks for the lesson and posting.

View DaleM's profile

DaleM

952 posts in 2847 days


#10 posted 07-28-2015 12:09 AM

I’ve been starting my old 1950s Delta drill press by hand every since I got it. I haven’t even tried to figure out what’s wrong with it yet, but this will give me some things to look for when I do. Thanks guys. I guess the only good thing about starting it turning by hand is you can turn it in reverse and it will go that way if you want or need it to.

-- Dale Manning, Carthage, NY

View bosum3919's profile

bosum3919

338 posts in 1082 days


#11 posted 07-28-2015 04:16 AM



I ve been starting my old 1950s Delta drill press by hand every since I got it. I haven t even tried to figure out what s wrong with it yet, but this will give me some things to look for when I do. Thanks guys. I guess the only good thing about starting it turning by hand is you can turn it in reverse and it will go that way if you want or need it to.

- DaleM

Dale,

I thought I knew my problem, but with good advice from the LJ community and YouTube I was soon on the right path. If I can help any way, just ask.

-- Bob

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