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Jet 1642 motor gone bad

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Forum topic by Underdog posted 05-11-2015 06:53 PM 1363 views 0 times favorited 35 replies Add to Favorites Watch
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Underdog

899 posts in 1496 days


05-11-2015 06:53 PM

Welp. It finally happened. I was turning some coffee table legs this weekend and the noisy motor got a LOT noisier. Time to do something about it.

I have a Jet EVS1642 that I bought new May of 2009. And unfortunately, it’s past the 5 year warranty date. By the time I noticed the noise, last year, it was already out of warranty. Darn.

The new motor is right at $460 and then there’s shipping. I called the local motor rebuilders, and their take is that it’s cheaper to buy the new motor than to rebuild this one.

I took the motor out and clamped it to my bench and tried to get it to make noise or wobble like it’s been doing under power, but it seems smooth as silk. Probably what’s happened is the rear motor housing has gotten wallowed out… and only when it’s under power does it give way.

Those table legs aren’t going to pay for this… Sigh.

Why’s a motor going bad on a 6 year old machine anyway? Not like I run the dog crap out of it running it a couple times a month….

-- "woodworker with an asterisk"


35 replies so far

View exelectrician's profile

exelectrician

2327 posts in 1888 days


#1 posted 05-11-2015 07:23 PM

Hmm, perusing the parts manual on pages 25 through 29 I came to the following conclusion the motor is a three phase unit (very robust usually) the problem is probably in the inverter unit (part # 64) Here is what I would do,
1. Do this check with the power off, spin the motor by hand and listen for any roughness, It should spin freely and quietly. If this test reveals a quiet motor then the problem lies elsewhere.
2. Check the lathe spindle and the pulleys, also check for missing teeth in the drive belt, If these parts are all okay, then the problem is most probably in the inverter unit.

Let us all know how your tests go, good luck.

-- Love thy neighbour as thyself

View Underdog's profile

Underdog

899 posts in 1496 days


#2 posted 05-11-2015 07:31 PM

Thanks for the tips, but there’s no way it’s the inverter. The inverter won’t cause the motor shaft to wobble. It’s definitely the motor.

-- "woodworker with an asterisk"

View MrUnix's profile

MrUnix

4208 posts in 1660 days


#3 posted 05-11-2015 09:06 PM

Making noise and motor shaft wobble sure sounds like bearings. I would open it up and check before writing the motor off completely. If you have already resigned yourself to buying a new one, it can’t hurt any. I’d also be suspicious of any motor shop that made such a claim over the phone without actually seeing the motor in person, but that’s just me :)

Cheers,
Brad

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

View exelectrician's profile

exelectrician

2327 posts in 1888 days


#4 posted 05-11-2015 10:40 PM

Oh, the shaft wobbles? Is the shaft bent? Most good motor shops could replace the shaft. But if it is just the bearings then it is a simple job to change the bearings, there are many good YouTube videos showing you what to do for three phase motors, not expensive at all, so good news, you should be up and running soon.
Or a replacement motor from Baldor through Global here: #VM3554T $341.95
http://www.globalindustrial.com/g/motors/ac-motors-2-phase/3-phase-general-purpose-motors/general-purpose-3-phase-200-and-575-volt-motors-103643

-- Love thy neighbour as thyself

View bigblockyeti's profile

bigblockyeti

3666 posts in 1181 days


#5 posted 05-12-2015 01:17 AM

Unless it’s a proprietary motor, used three phase units can usually be had very inexpensively. What is the motor frame size as listed on the nameplate?

View Underdog's profile

Underdog

899 posts in 1496 days


#6 posted 05-12-2015 02:55 PM

Yeah. Bent shaft. The weird thing is that the pulley doesn’t wobble UNTIL it’s under power. Just spinning it by hand won’t make it wobble or scrape. Smooth as silk.
The magnetic force has to be pulling it to one side.

I pulled it apart last night and got a look. The armature is scraping the stationary coil laminations and popped quite a few out of place. The armature is loping, or jumping rope. The bearings are still in good shape, and the end caps aren’t wallowed out. So basically the shaft has gotten bent somehow.

HOW? I have no friggin idea. This thing has been in my shop for the last 6 years and used probably on average a couple times a month. Never transported anywhere except when bringing it home the first time. Never been dropped or hammered on. Never had the motor off, never had changed the belt even…

Here are some pix.
Here’s the tag:


You see where the armature has been scrubbing on one side. I mounted this between the 60 precision centers on the lathe, and turned it by hand. You can see it loping, even though the ends of the shaft don’t really move much.

If you look close you can see where the armature hit the laminations and has pushed several out of place:

-- "woodworker with an asterisk"

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Underdog

899 posts in 1496 days


#7 posted 05-12-2015 02:58 PM

As for the replacement Baldor motor, there’s a great thought. I’m all for spending less money if the quality is at least the same, and it will actually replace this one. If the quality is better, and I mean that the shaft won’t bend under normal use, then so much the better.

-- "woodworker with an asterisk"

View WoodNSawdust's profile

WoodNSawdust

1417 posts in 637 days


#8 posted 05-12-2015 03:26 PM

Baldor is a well know manufacturer of quality motors. I would not hesitate to use one as a replacement.

-- "I love it when a plan comes together" John "Hannibal" Smith

View MrRon's profile

MrRon

3926 posts in 2704 days


#9 posted 05-12-2015 03:46 PM


Baldor is a well know manufacturer of quality motors. I would not hesitate to use one as a replacement.

- WoodNSawdust


Some Baldor motors are now made in China. Check out this site for 3 phase motors: https://www.surpluscenter.com.

View MrUnix's profile

MrUnix

4208 posts in 1660 days


#10 posted 05-12-2015 03:56 PM

You will be hard pressed to find a better motor than a Baldor. Absolutely better quality than that made in Taiwan thing you have now! However, I find it hard to believe that the armature could be bent from use, as they are pretty stout and would require quite a bit of force to damage. If it really is, then it most likely had to have been that way since it left the manufacturer. But, the damage you see looks exactly like what happens when bearings start to fail. It might be entirely possible that cleaning up the worn areas a bit and replacing the bearings could be a cheaper alternative than a motor replacement. Even though the bearings ‘look’ good, they can be worn enough to allow enough lateral movement under power to cause the contact damage you have. Would cost less than $20 to test that theory :)

Cheers,
Brad

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

View bigblockyeti's profile

bigblockyeti

3666 posts in 1181 days


#11 posted 05-12-2015 04:02 PM

I hate it when they don’t list the frame size so everything has to be reverse engineered to end up with a quality product instead of just making something worth a darn in the first place. $460 for a motor that doesn’t even have a frame size listed is about $459 too much. I bought a brand new 6 pole 3 phase Toshiba motor for my drill press to be used with a VFD. I think I paid $40 from a local industrial surplus center. I looked up the MSRP and it was just under $1100. That might be a thought, surpluscenter.com is basically the same, only everything is online and shipping can get steep pretty quick with something that weighs as much as a motor. Looking at the parts list online, it really looks like a 56C frame which is fairly ubiquitous and even brand new for a quality motor shouldn’t be over $300. Do you have shaft, key and mounting bolt diameter and pitch dimensions? Those could indicate if it actually is a standard frame size.

View Underdog's profile

Underdog

899 posts in 1496 days


#12 posted 05-12-2015 04:09 PM

No, I’d have to measure all that.

And NO the bearings are NOT bad. I’d know. I’ve replaced enough as a mechanic and maintenance man to know what a bad bearing is like. For them to be bad enough for this much movement in the pulley, and those bearings would be absolutely grinding… And they aren’t. They don’t even make any noise when you spin them by hand. No roughness, no noise. Smooth as silk…

I mean come on. If I can SEE the lope in the armature when the shaft is mounted between centers and rotated by hand, and the bearings are totally out of the picture, what makes anyone think that it could be bearings? I don’t even have to measure the runout in that armature to see that it’s past the point that bearings would fix it.

Don’t you think I’d jump at it if it could be fixed that easily?

-- "woodworker with an asterisk"

View MrUnix's profile

MrUnix

4208 posts in 1660 days


#13 posted 05-12-2015 04:23 PM

Don t you think I d jump at it if it could be fixed that easily?

Was just a suggestion :)

And was based on rebuilding a lot of motors that had the exact same damage. The fact that the noise progressively got worse over time and use, combined with the damage seen, was what prompted it. Bearings can go bad without showing any indication or making any noise. A worn bearing still full of grease will appear perfect until loaded up.

Again, it was just a random thought thrown out there for consideration… feel free to ignore it :)
I guess your next move is to try and find a suitable replacement… bummer.

I mean come on. If I can SEE the lope in the armature when the shaft is mounted between centers and rotated by hand, and the bearings are totally out of the picture, what makes anyone think that it could be bearings? I don t even have to measure the runout in that armature to see that it s past the point that bearings would fix it.

Another random thought – spinning it between centers might not prove anything. The critical area is between the bearings, and the shaft end past the bearings may have runout that won’t cause clearance problems between the windings/armature. It would cause uneven wear in the bearing on one side though. Just saying.

Cheers,
Brad

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

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Underdog

899 posts in 1496 days


#14 posted 05-12-2015 08:40 PM

I’ll humor you and double check those bearings… Perhaps you’re right. But I’ve been doing some perusing of the internet, and apparently Jet had a bad batch of these motors. I just haven’t used it enough for it to show up until now.
Gonna lobby for help with Jet customer service…

-- "woodworker with an asterisk"

View TheDane's profile

TheDane

4997 posts in 3124 days


#15 posted 05-12-2015 08:46 PM

Gonna lobby for help with Jet customer service…

That sure won’t hurt … they may cut you some slack since it is a evidently a problem they have run into before. I had a problem with my new Jet bandsaw several years ago … not only did they come up with a solution, they sent me a free set of clamps for my trouble.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

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