LumberJocks

Who uses compressor motors?

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by nicksmurf111 posted 06-07-2014 04:34 AM 1270 views 0 times favorited 12 replies Add to Favorites Watch
View nicksmurf111's profile

nicksmurf111

361 posts in 918 days


06-07-2014 04:34 AM

Topic tags/keywords: compressor motor electric dust

I was wondering how many of you used compressor motors on your woodworking equipment? What’s your opinion? Have you had much trouble clogging them up with saw dust? So far I got a Leeson 3hp, Century 2hp and Century 1hp. I paid $30, $40, and $20 for them. I feel like I stole them in comparison to current retail prices. I just moved the 3hp to my Belsaw planer, 2hp to my 14” Delta bandsaw, and 1hp to my 6” delta shortbed jointer. I need to create a homebrew stand that has some dust control for the jointer, the tin one it came with didn’t have a dust shoot.

Nicholas

-- Nicholas


12 replies so far

View ,'s profile

,

2387 posts in 3014 days


#1 posted 06-07-2014 04:50 AM

I think most of our motors are TEFC motors, not compressor motors. In the end, dust will get into a totally enclosed motor as well.

No real advise as to your motor situation.

I will say that we really love our woodmaster, which is very similar to your Belsaw. You have a very nice planer in that Belsaw I believe.

Have fun woodworking…

-- .

View MrUnix's profile (online now)

MrUnix

4244 posts in 1666 days


#2 posted 06-07-2014 04:54 AM

Most air compressor motors are not designed for continuous duty.. look at the time rating on your motors and verify they are rated “CONT” (continuous), as otherwise you risk burning them up pretty quick.

Cheers,
Brad

PS: they also usually have thermal overload protection that automatically resets, instead of manual reset.. which is a safety issue.

-- Brad in FL - To be old and wise, you must first be young and stupid

View William Shelley's profile

William Shelley

151 posts in 936 days


#3 posted 06-07-2014 05:53 AM

a TEFC is, for all practical purposes, completely impervious to dust. Because typically the bearings are shielded, which would be the last possible entry point.

On the other hand, a washdown motor is going to be even “better” (and holy-crap expensive), but you can, of course, wash it down.

My dad has a grizzly table saw with a ODP motor and the centrifugal switch got gummed up last year but other than that it seems to work fine.

For those prices you stated, you made off like a bandit.

EDIT: Also if you don’t see a duty rating, there should be a ‘service factor’ which, if it’s greater than 1.0, means the motor can run at 100% speed continously. A motor with a service factor of 1.25 can be run with a 25% increased speed (via a variable frequency drive, for example). Most motors have thermal overload protection as well.

-- Woodworking from an engineer's perspective

View nicksmurf111's profile

nicksmurf111

361 posts in 918 days


#4 posted 06-07-2014 09:15 AM

I’ve never seen a compressor motor that wasn’t rated for continuous duty. I believe that may be a myth (that they are commonly used on compressors). The reason I’m bringing this up is because of how this, at those prices, has allowed me to get setup. Even if I need to crack open one of these motors every couple years to clean the swich or change the bearings, that is easy to do.

From what I understand service factor had to do witg availalbe hp, not speed. We are talking about single phase motors here.

There has to be a bunch of people using drip proof motors for their machines. Let me know.

-- Nicholas

View nicksmurf111's profile

nicksmurf111

361 posts in 918 days


#5 posted 06-07-2014 09:20 AM

MrUnix, I’m calling you on the carpet, I think your “most” clame is invalid. We are talking about belt drive air compressors with single phase motors. I dare you to find one that isn’t rated continous duty. Many folks beat the daylights out of them grinding on cars with an undersized compressor. They are designed to withstand that.

-- Nicholas

View bigblockyeti's profile

bigblockyeti

3668 posts in 1188 days


#6 posted 06-07-2014 01:22 PM

I have TEFC motors on over 90% of my wood working equipment as being totally enclosed removes the possibility of dust ingress. Of the thousands of induction motors I’ve worked on, far less than 1% have been anything less than continuous duty rated.

View Shawn Masterson's profile

Shawn Masterson

1297 posts in 1416 days


#7 posted 06-07-2014 02:00 PM

they work fine. Just be aware of it and blow it out once in a while. my 50’s delta jointer has an open frame motor and it appears to be original. twice a year I blow it out.

View MrUnix's profile (online now)

MrUnix

4244 posts in 1666 days


#8 posted 06-07-2014 08:02 PM

LOL.. ok, maybe not ‘most’, but not all are rated for continuous duty, which is why I mentioned it and something that you need to check for. Even so, they will still work fine as long as you operate them in accordance to their rated specs. I think the confusion stems from the fact that many manufacturers/retailers list classifications such as “Farm Duty”, “Compressor Duty”, “Fan Duty”, “General Purpose”, etc.. when in fact those classifications are pretty much arbitrary and vary from company to company. Both NEMA and IEC have specific duty classifications that are much more meaningful.. NEMA has basically three: Continouous, Intermittent and Special (usually expressed in minutes). The IEC breaks it down into 8 classifications which are pretty much the same but with more granularity between classifications: S1 and S6-S8 are continuous duty classificatons with various conditions applied, while S2-S5 are intermittent duty, again with various conditions applied (load types, starting conditions, breaking, speed, etc..).

As for enclosure type.. ODP motors have been used for decades on WW tools. My 1954 Boice Crane jointer has its original BC badged ODP motor and it’s still working just fine. My 1950 Delta BS is the same. TEFC motors are nice, but not a necessity. Like Shawn says, blow them out every now and then if you have any concerns.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

View MrRon's profile

MrRon

3927 posts in 2711 days


#9 posted 06-07-2014 11:08 PM

I have an open frame motor on my drill press. I’ve use it for 30 years and never blew out the motor with air. It just keeps on running. The motors that were built way back were built to last.

View runswithscissors's profile

runswithscissors

2192 posts in 1492 days


#10 posted 06-08-2014 01:20 AM

Here’s another angle I’ve heard/read, though I can’t verify it. Compressor motors have to start against a load, sometimes a considerable load if the pressure regulator is set to come on well before the tank is emptied. I’ve seen a compressor motor (didn’t check out any details about the motor itself, however) that couldn’t start the compressor because it was at the end of a very long, not very heavy gauge extension cord (even though the compressor and the outlet were only about 6 feet apart). I realize that was a voltage drop issue, but it does illustrate the stresses a compressor subjects a motor to.

I notice that many motors say “not for compressor use.” I’ve never seen one that says “for compressor use only.”

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View Shawn Masterson's profile

Shawn Masterson

1297 posts in 1416 days


#11 posted 06-08-2014 01:28 AM

I will never understand people saying compressors start under load. every compressor I have ever worked on had a check valve, and an unloader valve. the check valve keeps the pressure in the tank, and the unloader valve bleeds out the pressure in the line from the head to the tank. so where is the load???

View nicksmurf111's profile

nicksmurf111

361 posts in 918 days


#12 posted 06-08-2014 01:28 AM

I think compressor motors are designed with a stronger staring winding, but I’m not sure if that’s true. I know all 3 of these motors that I’m putting to use gave a LOT of starting torque.

I’ve experienced the extension cord thing first hand. I’ve lectured coutless people. My buddy almost junked a compressor that he thought he burnt up, he didn’t know it overheated due to the 16 gauge cord.

Yes all compressors have unloader and check valves. People are dumb, that’s why. That’s why I was wondering how many people were thrifty enough to use second hand motors.

The load is the flywheel inertia and the unloaded pistons and valves.

-- Nicholas

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