Old jet bandsaw motor

[Derek Voigt]

I have an older Jet 14” (blue color not white) closed stand, with the 6” riser block. I recent acquired some large chunks of wood that I wanted to process into 16” bowl blanks. So I basically split the log down the middle leaving me with half circles about 18-20” long and about 8” radius (from the cut face at the pith to the bark edge.



Before I mount them on my lathe I wanted to get them basically round, so I made a circle cutting jig to us on my band saw. The pieces are large (as they are half a tree trunk) about 8” tall when I lay it face down to run it through the bandsaw. I cut a few round blanks but it was a lot hard then I thought and I had A LOT of blade twist and drift. I figured the blade was old and dull so I broke out a brand new resaw blade that is 3TPI and gave that a shot. The results were better at first, no blade twist and it seems to require less effort to cut. However, at the deepest point of the cut I started tripping breakers and the motor ended up getting super hot and there is a smell of burning. I eventually was able to back out the in process bowl from the saw and turned on the saw with no load and the breaker tripped.

Did I fry my motor, or does it just need some time to cool off? Is it worth replacing a motor, or should I start looking for deals on the new Laguna saws? (I really like the newer 14” saw with 14” resaw and 3Hp motor)

[Larry Komroff]

Derek,
I am assuming you have a single phase motor on the band saw. If you slowed the motor down to the point the centrifugal switch in the motor engaged and then wouldn't release, it could cause the symptoms you describe. You would need to "unstick " the switch witch is usually located behind the rear cover. Hopefully the start winding is not burned up. Another possibility is a capacitor is blown. You might want to look under the "humps" on the motor. They can be checked with an ohmmeter but if there is oil all over or it shows signs of melting, then the cap is bad. Please let us know what you find.

Larry

[Derek Voigt]

Ok thanks for the info. I have a juijitsu tournament this weekend, so it will probably be next week before I can check into it.

derek

[cody michael]

I have the same saw, I have cut blanks on it bigger then that... hopefully yours is ok

[Derek Voigt]

After a couple days of rest I tried to start the saw and it instantly trips the breaker, no movement. I might try to pull the motor out this weekend and see what I can see.

When I opened up the back of the saw and looked at the motor, I did notice some drips of what looks like wax on the floor directly under it. Any idea what that is from?

[Allan Speers]

After a couple days of rest I tried to start the saw and it instantly trips the breaker, no movement. I might try to pull the motor out this weekend and see what I can see.

When I opened up the back of the saw and looked at the motor, I did notice some drips of what looks like wax on the floor directly under it. Any idea what that is from?

That has to be either bearing grease or melted insulation. Is it hard, or sticky?

Do the bearings turn freely? If not maybe you can just re-lube them (I'm not sure) or worst-case replace them. If insulation melted, you got problems.

You should try to find a motor rebuilding place nearby, and have THEM check it out. They can run a continuity check on the windings, etc.

BTW - Did your bandsaw NOT have heaters? If not, consider getting a mag starter once things are running again. The heaters' job is (primarily) to pop open when the motor overheats.

[Derek Voigt]

It is hard and feels like wax.
I didn't try to spin at the motor, so I'll have to try that.
There was no breaker or anything on the motor itself. I just tripped the 20amp breaker for the outlets it was plugged into.

[Allan Speers]

It is hard and feels like wax. .

So you melted your insulation. Time to have the motor rebuilt.

- Or look at the bright side: Now you have a good excuse to finally upgrade to a 2 HP motor !


If you can find a 2-3 HP, 3 phase induction-rated motor (the kind typically with external fins) with the proper mount, and an inexpensive VFD inverter like TECO, you can even have vari-speed, to some degree (+ / - about 50% with the very best motors, + / - 20% with a non-inverted rated motor) which could be useful for things like cutting aluminum & brass.

Also, if your Jet has no brake, the 3phase / VFD combo gets you dynamic breaking.

And if you have no mag starter, which you probably don't which is why you have this problem in the first place, that $200 VFD takes the place of the mag switch, so it's money well spent.

Dump the old motor and be happy.

[Derek Voigt]

From what I have read finding a replacement motor that will easily fit with the saw without modification is difficult and a factory replacement is like $400.

Anyone have any ideas?

[Allan Speers]

From what I have read finding a replacement motor that will easily fit with the saw without modification is difficult ....

Why? Is it a direct drive?

If it's a vintage JWBS-14CS, then it's your standard "motor in the base, with a pulley on its shaft, and belt going up to the wheel pulley" design.

You should be ale to mount any counter-clockwise motor with a flanged base in there, by installing a hinged platform. (The hinge is so you can adjust belt tension.)

[M Toupin]

From what I have read finding a replacement motor that will easily fit with the saw without modification is difficult and a factory replacement is like $400.

Anyone have any ideas?

From the sounds of it I'd venture a guess that Larry may be correct in that bogging down the motor allowed the centrifugal switch to re engage the start windings and caused the overheating. Though that's complete speculation on my part from a couple hundred miles away. I'm also guessing that the waxy substance is the remnants of the grease from the bearings. If the BS is more than 20 years old, which the blue color indicates, and the bearings are original (good bet) then the lubricants (oils) in the grease are long gone which just leaves the carrier which is a soap (waxy) emulsification.

Pull the motor out and look at the data plate. The data plate will have a frame size code which I'm guessing is probably a 56 series. The frame sizes are standard indicating the mounting hole pattern, shaft size, distance from the base to center line of the shaft etc. Just replace the motor with a identical frame size and RPM and you'll be back in business. WW manufactures seldom if ever manufacture their own motors, they're just off the shelf standard motors. The last place I'd look is Jet, the mark up is crazy! Personally I'm a fan of quality stuff but if it was my BS I'd just stick with inexpensive. A 1.5 hp motor should run in the $150ish range. Putting a $4-500 Baldor or Leeson on a $200 BS doesn't make much sense nor does going crazy with a motor starter or VFD.

Mike

[John Lanciani]

... Putting a $4-500 Baldor or Leeson on a $200 BS doesn't make much sense nor does going crazy with a motor starter or VFD.

Mike

+1. The saw is only worth +/-$200 in running condition. Putting a big motor and a VFD on it is akin to putting lipstick on a pig. 1 or 1.5 HP motors are readily available from places like surplus center for reasonable money and there is no reason to put a magnetic starter on this saw other than to spend extra money needlessly.

[Allan Speers]

+1. The saw is only worth +/-$200 in running condition. Putting a big motor and a VFD on it is akin to putting lipstick on a pig. 1 or 1.5 HP motors are readily available from places like surplus center for reasonable money and there is no reason to put a magnetic starter on this saw other than to spend extra money needlessly.

Nonsense.

Having a brake & protection from post-blackout starts are both excellent safety factors, whether the saw is worth $2,000 o $50. Every machine should have them. You might as well say, "well, I wouldn't bother with a good dust collection system, because that would cosy 4X what the saw is worth."


Of course, it might make more sense to sell the saw for parts, and buy something better, (I would) but that's a different subject altogether.

[Dave Cav]

If the motor trips the breaker instantaneously then that means you probably have a dead short to ground somewhere.

If you have a "waxy substance" on the floor, my first suspicion would be that some of the sealing compound has leaked out of the start capacitor. I don't think I have ever seen bearing grease leak out of a small motor like this and on to the floor.

If it's a 1 HP motor, it is not economical to have rebuilt at a motor shop. The rule of thumb used to be that unless a motor was at least 5 HP, it wasn't worth rewinding.

Pulling out a motor, tearing it down and going through the parts with a meter is a fairly straightforward process if you know what you're doing and understand how the components work. Repairing and replacing centrifugal switches and replacing start capacitors isn't a huge task, again, if you have some experience in this area. If the windings are burned (burned windings have a very characteristic odor you won't forget), and/or shorted out, then the motor is no good.

The best course of action, assuming you aren't comfortable with a bench teardown, would be to find the cheapest replacement available and drop it in. Grizzly and even Harbor Freight sell reasonably priced replacement motors; I have been using a replacement HF motor in a horizontal band saw for years with no problems.

[John Lanciani]

Nonsense.

Having a brake & protection from post-blackout starts are both excellent safety factors, whether the saw is worth $2,000 o $50. Every machine should have them. You might as well say, "well, I wouldn't bother with a good dust collection system, because that would cosy 4X what the saw is worth."

So now the 1000's or 10,000's of small home shop bandsaws that are used safely and reliably every day for the past 80 or so years without either of these features are suddenly unworthy of use? Did the 14" Delta that you had (or maybe still own) and have over and over professed to be the best 14" saw Delta ever made incorperate either a VFD or a brake or magnetic switch with heaters? Seriously, The OP needs to replace the motor with one of identical size and quality and get back to work.