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Belt/Disc Sander Motor Question

7.1K views 21 replies 7 participants last post by  RedBarnRob  
#1 · (Edited by Moderator)
I found a JET JSG-6DC combination belt/disc sander on Craigslist. It includes a 1.5 HP motor that is wired for 110 VAC power and requires a 30-amp circuit to run. The person selling it doesn't have a suitable circuit in his house, so I am unable to test the sander. He says that he bought it at auction from his father's workplace when they were selling off a bunch of equipment and that it worked at the house he moved from two years ago, but would consistently trip the circuit breaker there, which also was not a 30 amp circuit. It would not even begin to turn at his current house without tripping the GFCI circuit breaker he had it plugged into.

I'm interested in it but would rewire it for 220 VAC in my shop. It's manual includes instructions on how to do that which are very straightforward. The belt and disc both turn freely by hand and feel solid, though I've obviously not been able to see it run at speed. My questions are these: If something had gone wrong with the sander, would it likely be anything other than the motor? And if the motor had died on it, how likely am I to find a suitable replacement that would fit?

My suspicion is that the sander actually runs. He's asking $450 for the unit, which seems reasonable if I could verify how well it works. I suspect I could buy it for less than that and am trying to work out what price at which I'd be willing to take a chance on it. Information on it is available on the JET site here.

Thank you for any thoughts you have.
 
#2 ·
I am no expert but it surprises me that a 1.5 HP motor requires a 30 amp circuit. Must have one heck of a start up surge. Did he show you the motor's name plate?

I suppose you might be able to rent or borrow a generator that can handle up to 30 amps, though I don't have any idea if that is a good idea or not?
 
#3 · (Edited by Moderator)
I'm not sure why they recommend a 30A circuit requirement - the manual states it has an FLA of 12.8A, so a 15 amp circuit should easily handle it, and the plug/outlet shown in the manual is the normal 15A variety. Something sounds goofy there.

As for the price - I wouldn't pay even half of the asking price for that machine, which appears just to be a grinder with sanding attachments bolted on instead of grinding wheels. They are probably nice machines, but I can't figure out how they justify the price they are selling those things for.

Cheers,
Brad
 
#4 ·
Good thought, Nathan. Here's the motor nameplate. It calls out 22A.
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Brad, I see that in the manual as well, but also the requirement for a 30A circuit with 115 VAC power. Inrush current at startup was my thought on why, but I don't know for sure.

Thank you both.
 

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#6 ·
A new Grizzly may be the better option, Brad, but the Grizzly unit I see has a smaller disc 9" vs. 12" (which isn't a big deal to me) and a much smaller motor, 3/4 HP vs 1-1/2 HP, which is a bigger deal to me, though admittedly most things I would want to sand on a unit like this are smaller and less likely to stall the motor out.

I would still like to figure out what could possibly be wrong with this unit and how likely I am to be able to replace the motor if that were a problem.

Thank you.
 
#7 · (Edited by Moderator)
If the larger disc isn't necessary for you, I would think that the smaller motor would be fine on the Grizzly. I built my own 6Ă—48 belt sander and just use an old 1/2 HP blower motor and it has plenty of power for anything I sand on it.

I wonder if you could get it to work on his existing circuit by removing all of the load from the motor by taking off the disc and the belt sander drive? If not and since he can't demo it for you but you still want to take a chance, I would only offer him half his asking price at the most and probably less. If you just have to replace the start capacitor, for example, ereplacement parts lists a new one at about $60, though you can probably find a compatible one for less. A new motor, because it is double shafted with a custom housing will probably cost you the price of a brand new Jet machine.

Personally, I would walk away.
 
#8 · (Edited by Moderator)
Just as a reference point, I have a DeWalt 6×48 w/10" disc sander (thanks to a fellow LJ Member!) that uses a pretty standard frame 3/4hp induction motor… so if the motor ever did let out its magic smoke, it would be pretty trivial to replace. It would be much more difficult (and probably much more expensive) to replace the motor on that Jet due to its design should you ever need to. BTW: I've done a lot of sanding on mine over the years, and I have never been able to stall it - and I don't think I could even if I wanted to.

Also, the further out on the disc you sand, the faster it is moving, so you can pretty easily burn your work piece unless you are very careful. With a 12" disc, that would be even more problematic. Most of the sanding on the disc is done towards the middle where it's not as critical. And for what it's worth, I do not use the disc nearly as much as I do the belt - but that really depends on the individual and what projects you use the machine for.

Cheers,
Brad
 
#10 ·
The asking price is usually more than what he will settle for. I wouldn't buy it without knowing if the motor runs or not. Jet usually makes good equipment and can be placed among such companies as Delta and Powermatic. Most if not all their machines are made in Taiwan, not China, which is a big plus. Not knowing how old the machine is, I would put a price of $300 on it. My take on it is; the older a machine is, it means to me it is better because it has lasted this long without any major failure. Failures usually begin to appear within the first year. This sander was in a commercial work place and probably saw much use and if it has stood up to a lot of use, it has proven to be a good machine. When I buy a machine, I always look for older machines because they have proven themselves over the years. Sure you don't get all the bells and whistles of newer machines, but that is not of basic importance.
 
#12 ·
RedBardBob: I did end up buying it. I was able to get it for $250, rewired it to 230 VAC and discovered the motor wouldn't start. It will turn slowly if I manually spin the shaft, but I suspect the start winding motor contacts are corroded. I found a YouTube video on how to clean them and plan to do that when I have a few hours in a row to work on it. I've also got a local motor shop lined up to look at it if needed. It might work, it might not. It was a good flyer for that cost.

What do you want to know?
 
#13 ·
It's usually the cap or the centrifugal switch.

Pull the cover off the pulley side and pull the rotor out. Sometimes you have to disconnect some wires to get enough room to pull the other side off and check the contacts. Most I've messed with had the mechanism on the rotor gunked up.
 
#14 ·
I was just looking for a wiring diagram to convert it to 230 V. The only ones I found online seem to be for the newer model and after a quick test I've determined that the directions don't apply to our model. I have four leads that need to be rewired one yellow one black one red and one gray just want to determine what's the proper configuration for 230. Any help will be much appreciated. You got yours for a great price. I hope you're able to sort out the issues you are having with it
 
#15 ·
I remember some confusion about that. The user manual is clear enough but the wire diagram on the sander itself messed me up. I called Jet customer service and they basically said to cut the gray and red wires from the motor side of the start/stop switch and to tie them together. Before and after pictures of the switch on my sander are below.

Before - 115 VAC
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After - 230 VAC
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The gray and red wires get tied together.
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I hope this helps. Gary
 

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#19 ·
Thanks again. That diagram appears to be different than the way you have it wired for 230. Could that be why yours is not working. The diagram appears they have black and yellow wire nutted together and gray and red going to switch. Unless I'm reading it wrong. But the 110 wiring diagram appears the match how you had it wired before you convert it.
 
#20 ·
I tried to based on the diagram… black and yellow together and gray and red to the switch and it worked perfectly. (I tried the way you have it and no luck).The wiring instructions you got from Jet is for the newer models and do not work for ours. Thank for your help. I hope this may solve your problem as well. Let me know.
 
#21 ·
That was it. I rewired based on that wiring diagram and your suggestions and it runs smooth. I was not aware that there was a newer version and believe the user manual I have is for the newer version as well. I had been using the wiring diagram in it and the direction from Jet customer service and not the diagram on the wiring cover. Thank you for your help. I really appreciate it. Makes my $250 flyer even better! I'm glad yours works as well. It is good that we could help each other!