2001 5 HP Powermatic Intermittent Power During Cuts

[Dale Osowski]

This just started happening yesterday. The saw is 20 years old however still in excellent condition, probably less than 40 hours actual use over those years. Anyway, while making a cut in 1.5" stock the power basically flicked on and off through the cut. I thought it may have been a freak thing and tried it again today and it did the same thing. It's a 5 HP with a sharp blade and I'm running it full 220 volts and 30 amp breaker. The motor starts fine and runs fine under no load. The motor doesn't come to a stop or slow but the power becomes intermittent. Belts are link belts with about 1/2" deflection. As said the saw is older but very light use. Any ideas?

Thanks!

[Maurice Mcmurry]

I would check for slipping belts, a pulley that has lost its key, or a slipping blade.

[Dale Osowski]

I would check for slipping belts, a pulley that has lost its key, or a slipping blade.

Very good possibility. I've been cutting a lot of Ebony lately. The dust is so fine and it's pretty visible on the link belts.

[Marc Fenneuff]

Start by removing the power, opening up the starter enclosure, and making sure all the wires are still securely connected.

[Maurice Mcmurry]

Does not sound electrical to me. Tighten those 20 year old belts, check the pulleys, and tighten your blade.

[Dale Osowski]

Does not sound electrical to me. Tighten those 20 year old belts, check the pulleys, and tighten your blade.

I'll tighten up the belts this weekend, they are actually only a few years old and maybe an hour run time on them total. I think the Ebony dust is the main cause of the problem, hopefully. ;-)

[Maurice Mcmurry]

Dale, What are you making with Ebony? I wish I has some.

[Dale Osowski]

Dale, What are you making with Ebony? I wish I has some.

Here is a link: https://sawmillcreek.org/showthread.php?296234-Krenov-Style-Apron-Plane

[Greg Quenneville]

If the belts are slipping and blade slowing, surely the motor sound would be the same, or louder. An intermittent electrical fault would be obvious by the changing motor (as opposed to blade) sounds.

As already mentioned, check all connections. Also check the switch for loose wires and dust. The plug connections and power cord too.

[Richard Coers]

A 1/2" of deflection is a lot for any style of belt. But I guess you don't mean an electrical situation when you say power? Most people assume power is electricity when running machinery. You really mean the blade is slowing or stopping and the motor remains at full rpm?

[Dale Osowski]

A 1/2" of deflection is a lot for any style of belt. But I guess you don't mean an electrical situation when you say power? Most people assume power is electricity when running machinery. You really mean the blade is slowing or stopping and the motor remains at full rpm?

It almost sounds like a clicking but that could just be the belts slipping then grabbing again. No slowing of the blade from what I see. I'm leaning more towards belts slipping because when run under no load there is no problem or strange noise. It's only when under a load that this has happened. At first I thought it could have been the overload protection but wouldn't that shut down the motor completely and require a reset? I won't have time to look at it more closely until the weekend or next week. Not a problem because I won't need to use it in order to finish up current projects. Just a little baffled and thinking about what the problem could be.

I probably won't get back here until tomorrow night so thanks for the replies everyone.

[Maurice Mcmurry]

clicking = lost pulley key (based on having had the same problem)

[Andrew Hughes]

I would like to add my experience with link belts. Once they start slipping they are done get rid of them. Buy a good cog belt. I recommend these ones I use them and find them smooth running and non slipping.
I have them on all my machines.
Good Luck

[Bill Dufour]

Maybe the tires are slipping so the blade looses power. Shut down and feel the belts and tires to see if they got hot from slippage. Does it have a transmission or variable speed reducer? Blow sawdust out of the stop switch contacts. Any burning rubber smell?
Bill D

[Michael Schuch]

My much older Powermatic 65 does the same thing every year or so. I blow all the saw dust out of the open frame motor and it is good for another year or so. If you have an open frame motor I would suggest blowing it out really well and see if that helps at all.

Slipping belts make a lot of sense too. I think you would notice some burning rubber smell from the belts slipping?

[Dale Osowski]

Well, it's not the belts. Today I was making light cuts in maple and it did the same thing. Went to make another cut and this time it sounded like the motor had a hard time starting, it hummed before starting. So, what could this be. I do have proper size breaker and the saw is wired directly into service panel with 8' of 10 AWG cord. Does this sound like something with the starter switch box or the motor? Could the clingy Ebony dust be causing this?

[Robert Hayward]

Motor capacitor/s.

[Tom Bender]

One simple test, mark the motor shaft and pulley. That should check the possibility of the key sheared or lost. A dot of paint or possibly tape, it may slip back to the same position.

[Dale Osowski]

Today I had a chance to pull out the capacitor cove, Ii was caked with dust but no burnt smell. I cleaned out all the dust and did a number of starts and runs. Regular start, stops and runs seemed fine but when I did a rapid stop and start it fluttered for a spilt second.I don't have a tester so is there a way to tell which capacitor is the bad one? I'll just probably replace the pair when budget allows.

That being the case will I harm the motor if I run it like this until I can replace the capacitors?

Thanks!476238

[Maurice Mcmurry]

That is some serious caked. I wonder if that amount of sawdust can conduct any electricity? It seems doubtful. If everything is not proper I suspect there is a chance for damage.

[Lee Schierer]

Today I had a chance to pull out the capacitor cove, Ii was caked with dust but no burnt smell. I cleaned out all the dust and did a number of starts and runs. Regular start, stops and runs seemed fine but when I did a rapid stop and start it fluttered for a spilt second.I don't have a tester so is there a way to tell which capacitor is the bad one? I'll just probably replace the pair when budget allows.

That being the case will I harm the motor if I run it like this until I can replace the capacitors?

Thanks!476238

If it doesn't want to start, it is likely the start capacitor. If it loses power while running it is the run capacitor. For sure, I would get rid of all of that dust. I would also check the centrifugal switch and cooling fan to make sure they aren't clogged with dust.

[Dale Osowski]

Ok guys, I need a little help finding the correct capacitors. I do a search via entering the numbers and when I click on links and a different part number and specs appear. Photos show what I need, both capacitors are the same number. These are are a 5 HP Baldor.

Thanks!

477053

477054

[Todd Sebek]

I had the exact same issue with my PM 8” jointer and I realized that one of the keys in the top pulley had shaken loose. I found it while I was sweeping up my floor (lucky me). I truly don’t know how the pulley wasn’t falling off. I reattached the key properly and got the right tension on the belt and it has been awesome since. Cost me no money. Hopefully that helps. I had the same radical pulley deflection and this buttoned it up.

[Maurice Mcmurry]

I did not get far with the Baldor part number either. Grainger has these two with your Uf specs. Check the measurements. Hopefully other contributors will double check.

477070 477071

[Bill Dufour]

The run and start capacitors will be 4-5 times different in MFD. Since they have the same number that number is probably just indicating physical size or terminal location/type.
After you clean the start switch I would run a strip of brown paper page through the contacts.Hold them lightly closed with finger pressure if needed. That is probably be enough to clean them of any crud. Using any file or sandpaper risks leaving conductive dust behind.

Bill D

[Dale Osowski]

Is it normal for both start & run capacitors to be the same? These seem to be what the saw & motor came with in 2001. Both are marked as 161 - 193 UF.

[Dale Osowski]

I'm thinking this set will do the trick but not sure about the bleed resistor. I assume it can be left off.

https://www.amazon.com/Pack-161-193-250-VAC-092A161B250CD6A/dp/B07XZM6TCY/ref=pd_ybh_a_1/146-9844479-5788060?pd_rd_w=tt1Ct&pf_rd_p=48b4f440-2099-4e34-afeb-210417d3bf51&pf_rd_r=6MTYTNWK1YVN30X33RR0&pd_rd_r=a1da2f31-ab63-4a96-a39e-b3012509c07c&pd_rd_wg=2zxtw&pd_rd_i=B07XZM6TCY&psc=1

[Bill Dufour]

No need for the bleed. Just be careful and aware they hold a charge after the power is off. You can short them with a screwdriver if you want.
Bill D

[Dale Osowski]

Just ordered two of these. They are a better fit in length & diameter than the ones in the Amazon link.

https://www.justcapacitors.com/product/161-193-mfd-x-250-start-capacitor-092a161b250be5a/

[Dale Osowski]

The new capacitors are in and I'm sure it's my imagination but it sure seems to start much smother. :-)

477343