LumberJocks

Diagnosis my tablesaw motor pop

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by Jeff_in_LSMO posted 11-28-2016 09:15 PM 852 views 0 times favorited 23 replies Add to Favorites Watch
View Jeff_in_LSMO's profile

Jeff_in_LSMO

347 posts in 2178 days


11-28-2016 09:15 PM

I’ve been putting more time in on my tablesaw lately, and today when cutting through a piece of thick maple the saw made a dull pop sound, stuttered a bit, and then I could smell electrical fault. I quickly turned it off, unplugged, and got the fire extinguisher at the ready.

After opening the cabinet, everything looks normal, except the, excuse my french, peckerhead was hot.

Given that I probably know the outcome, what happened? Is that the end of the motor?

UPDATE: got to taking apart the motor; here is what’s left of the capacitor


23 replies so far

View HerbC's profile

HerbC

1687 posts in 2697 days


#1 posted 11-28-2016 09:30 PM

Toast?

Hopefully not. Might be just a lead shorting out in the p-head. Disconnect the power, say a prayer and open up the connection box and check it out.

Good Luck!

Be Careful!

Herb

-- Herb, Florida - Here's why I close most messages with "Be Careful!" http://lumberjocks.com/HerbC/blog/17090

View MrUnix's profile

MrUnix

6006 posts in 2037 days


#2 posted 11-28-2016 09:35 PM

Would be kind of helpful if we knew what kind of saw/motor you have. Just pulling stuff out of thin air, maybe the centrifugal switch spring broke? If it was still running when you cut power, it ain’t toast yet and probably an easy fix.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View splintergroup's profile

splintergroup

1702 posts in 1060 days


#3 posted 11-28-2016 09:35 PM

Could be an internal breaker popped or the start/run capacitor let out the magic smoke. Motors are generally well protected these days.

View mahdee's profile

mahdee

3828 posts in 1606 days


#4 posted 11-28-2016 11:31 PM

I am thinking the capacitor. Mine did the same thing but it was the bearing that had seized up.

-- earthartandfoods.com

View CLowery15's profile

CLowery15

24 posts in 721 days


#5 posted 11-29-2016 01:22 AM

I just replaced the run capacitor on my Craftsman Contractor Table Saw…the old one was a Ming Fun capacitor from Taiwan, which I wasn’t going to try and find…so I wired in a 30 microfarad, 370vac run capacitor…the saw runs much much quieter.

-- - Craig

View Jeff_in_LSMO's profile

Jeff_in_LSMO

347 posts in 2178 days


#6 posted 11-29-2016 02:06 PM

excellent to hear clowery15. Not being good with electronics, what do i do? What does a capacitor look like? How do i know if it is bad? How do I replace it? etc?

View WhyMe's profile

WhyMe

910 posts in 1399 days


#7 posted 11-29-2016 02:24 PM



excellent to hear clowery15. Not being good with electronics, what do i do? What does a capacitor look like? How do i know if it is bad? How do I replace it? etc?

- JeffinLSMO

If you search the web for “test and replace motor capacitor” you’ll find plenty of information. Lots of YouTube instructions.

View Bonvivant1's profile

Bonvivant1

31 posts in 813 days


#8 posted 11-29-2016 06:18 PM

If you are going to tackle a change of capacitor make sure you read about discharging capacitors. A capacitor can contain enough of a charge to potentially kill you. Some people simply place a screw driver across the terminals to discharge a capacitor. I think this is dangerous. I use a contraption I rigged with a light bulb. You can also use resistors, depending on the size of the capacitor. Be safe!

-- You took your first pinch like a man and you learned the two greatest things in life...Never rat on your friends and always keep your mouth shut.--Jimmy Conway

View MrUnix's profile

MrUnix

6006 posts in 2037 days


#9 posted 11-29-2016 06:35 PM

Given that there was an audible ‘pop’, you should be able to instantly tell if it was the capacitor, as it would be split open or otherwise show signs of an unusual failure. Capacitors rarely explode… usually it’s the dielectric fluid that breaks down over time, sometimes resulting in bulging or leakage, but not always. If there is no physical damage that can be detected, it can easily be tested with a multimeter on its resistance setting.

But since there was an audible clue – that points more to a mechanical failure. Most likely will require opening up the motor to see what happened. Without knowing what type of motor we are talking about, it’s still all just a guess though.

Cheers,
Brad

PS: The capacitors on a small motor won’t store enough juice to do much damage, and shorting the terminals out with a screwdriver works just fine. If you were playing with the capacitors in something like an old TV or microwave oven however, that is a different story!

-- Brad in FL - In Dog I trust... everything else is questionable

View Bonvivant1's profile

Bonvivant1

31 posts in 813 days


#10 posted 11-29-2016 09:35 PM

I have no idea whether the capacitor would hold enough charge to hurt the OP. However, either way I would be careful.

As to discharging a capacitor with a screwdriver, I know it is done a lot, however, it is not the proper way to do it.

-- You took your first pinch like a man and you learned the two greatest things in life...Never rat on your friends and always keep your mouth shut.--Jimmy Conway

View CLowery15's profile

CLowery15

24 posts in 721 days


#11 posted 11-30-2016 02:30 AM

Hi Jeff…well, first, the capacitor stunk, then when I took off the metal cover, it was bulging out in several areas. The capacitor I reploneaced it with was a 2” diameter capacitor…granted it didn’t fit in the metal case. so, I zip tied it to the outside of the motor and wired it up.

Put several pieces through the saw this evening and it runs great. I don’t know what saw you have, but the one that blew in mine was rated at 30 microfarad / 350vac. So, you want to go up in voltage, not down & keep the microfarad rating. That’s why I went with the 30 microfarad / 370 vac capacitor. $13.25 as compared to $150.00 was an easy sell.

replacing is simple…even though a new one will have several areas for connections, I had 2 wires that came from the motor…I simply crimped a male connector on each wire, and slid them on each side…just place the crimped wire on each side and you should be good to go.

Hope this helps & best of luck!

-- - Craig

View Jeff_in_LSMO's profile

Jeff_in_LSMO

347 posts in 2178 days


#12 posted 12-01-2016 06:37 PM

update, the capacitor was done. see pics.

View Jeff_in_LSMO's profile

Jeff_in_LSMO

347 posts in 2178 days


#13 posted 12-01-2016 06:57 PM

so how do i know if this is the starting or run capacitor, and how do i select a replacement? i’m pretty sure it is a start capacitor.

View MrUnix's profile

MrUnix

6006 posts in 2037 days


#14 posted 12-01-2016 07:09 PM

Everything you need to know is written on that label stuck to the side of the capacitor. Can’t really read it good, but looks like 35uF?? Can’t make out the voltage. Maybe post a better, non-blurry picture.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Jeff_in_LSMO's profile

Jeff_in_LSMO

347 posts in 2178 days


#15 posted 12-01-2016 07:16 PM

Huizhong CBB60
35uF +/- 5% SH
250 VAC 50/60hz
25/70/21 C P0

showing 1 through 15 of 23 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com