Why is my lathe not running?

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GouletPens

GouletPens

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Joined
Nov 9, 2008
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1,449
Location
Ashland, VA
I have a Delta Midi, but that's irrelevant b/c I replaced it with the PSI 1/2 hp VS motor. For some reason today, it stopped working. I hit the reset button, checked the motor brushes, the lathe turns freely, there's no visible damage anywhere, so what could it be? The only real clue I have is that for a few on/off tries it would start to turn for about 1/2 second then stop. It's not even doing that anymore. I'm thinking it might be the on/off switch?
 
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Can you wire it around the on/off switch and see if the motor comes to life? If so, the on/off switch is shot. If not, the motor is shot. You should be able to route the wires directly into a 3-prong plug and see if it works.

The only other thing I can think of is to check your breaker and your GFI.
 
Another option, from PSI's website:

Your lathe has a motor equipped with carbon brushes (ZTCL4-
68). They and the commutator need periodic maintenance. During
break in and high power usage, a carbon track may be formed on the
commutator. This carbon track will insulate the brushes from the
commutator causing poor performance and eventually stopping the
lathe. Remove the brushes and clean the commutator with a new
pencil eraser through the brush port. If the brushes are not broken in,
shape them with a round file leaving a crescent shaped indentation in
the brush end approximating the diameter of the commutator.
Reinstall brushes so this indentation is oriented to the shape
of the commutat
 
If it's the start capacitor, it would normally run after you manually spin it up. But if the VS motor is bigger than the OEM motor, the switch may have arced internally, like Keith said. If it's not the switch, you'll have to consider the VS electronics...
 
I had a PSI variable, and this happened frequently. I sent back the power box and they switched out some circuit boards, but it continued to happen. I bought a Jet and haven't had a problem since. I suspect that the motor cannot handle any significant load and shuts down when overloaded. Give it an hour and it will start again. I just didn't have a hour down time to give to a 30 minute project.
 
maxwell_smart007 said:
I doubt the motor is 'shot'...likely, it's your start capacitor...

Is there a cigar-shaped bump on the motor housing - that'd be your start capacitor...I hear that they tend to go from time to time...
Click to expand...

Could be wrong; but I am reasonably certain that DC motors don't have start capacitors??

Brian: One thing to check on VS systems, when they just quit, is the circuit board. Most of them have a fuse that can blow or be defective. However, a blown fuse would cause the lathe to quit dead and not offer any 1/2 sec turns.

It certainly would be easy enough to check the switch and worth doing since they are usually a weak link; but I think it is more likely to be a component on the circuit board (other than the fuse) which will necessitate a replacement of the entire board or the complete VS control box at PSI's discretion.

I think you need to get on the horn and chat with the techies at PSI. Hope that thing is still under warranty!!
 
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Brian,

I have the same set-up and that happens regularly to me after I have used it for an hour or so. I have found that if I tap lightly on the box, it usually starts up. Once it begins to stop, I often have to tap it about every 3 to 10 minutes. Plum aggravating! I don't dare tap it hard, just jiggle it as though there is a loose connection.

Because so many people have reported this I feel that it might be something in the adjustable rheostat and not a loose wire. It could be the brushes as the web site mentions but I don't think this is the problem after 1 1/2 years. (Could be though.)


I am comfortable with electronics and one of these days, if I am not in the middle of something that can't wait, I am going to take that box apart and look at it. And then I will check the brushes.
 
Only north of the border --

The electronics change the ac to pseudo dc to provide variable speed -- at about 90 volts max. Sounds like connectors are not solid. I have not had that problem with the PSI swap out I have

(and yes, DC motors do not have a capacitor start -- that is on AC motors to decrease the voltage drops on startup with extra voltage capacity - or close to that -- been along time since college class in circuits).
 
i have a jet mini vs and had the same problem. It was the switch. I took it out and went to ace hardware and they had one almost identical. I had to grind down the terminals on the switch so it fit the connectors in the lathe. All in all it only took about 30 minutes, including the trip to ace.
 
In an effort to not offend anyone by stating something simple I will tell on myself.:tongue:

I have old outlets in my shop. Sometimes somthing similar happens to me and I have to wiggle the plug in the outlet. It is not unplugged, but the contact in the outlet are old (I know I need to replace it, but that would ruin the story) so it just doesn't get good power. I get about 1/2 revolution and then nothing. Wiggle (perhaps Jiggle for the Canadians) the plug and all is good again.
 
Just have to speak up on an issue that I do know about. DC motors don't have or need a starting capacitor. On an AC motor, a capacitor is used at start time to produce a phase offset between voltage and current so there will be torque in a predictable direction upon starting. On an AC motor when the capacitor goes bad, you can usually get the motor to rotate in either direction just by spinning it.

My money is on the brushes. Sometimes just removing them and replacing them will reconcile the issue temporarily. If it is the brushes, they are usually inexpensive.

Sorry guys, I just had to geek out for a short while.

John
 
Brian,

Just happened to my variable speed PSI. It's the switch. They swapped mine out and it now works fine. Had same symptoms. They are warranteed for 3 years.

Ken
 
I have had this happen to several of my tools over time. It is the switch.

Easiest and cheapest thing to do is disconnect power. Take switch apart and inspect contact points. I would be willing to bet that the contact points in the breaker switch have "gump" on them. This has happened to my lathe, table saw, router table and dust collector twice. I little bit of effort with a brass wire brush will do wonders.
 
jedgerton said:
... Sorry guys, I just had to geek out for a short while.

John
Click to expand...

Being a geek is good, very good in my book. Especially in a reply of this nature!

I also concur with your expressed opinion. :smile:

KIRK ... replace that outlet ASAP and any other that may have the same characteristics! Arcing in any switch is an excellent source of fires in your home. Ask our fellow IAP Firefyter about this and he will tell you some horror stories I am sure of fires hidden in walls and not noticed until the home/shop was engulfed in smoke and flames. Let's see now ... cost of home and everything vs a $3.50 switch! Hummmm, no doubt in my mind which I would choose!

I hope this is sufficient to scare the hell out of you and anyone else that won't perform preventative repairs ... Git'er done, dude! :eek:

DO THE REPAIRS NOW before it is too late. It will only take a few minutes to change out and you can then go about business in safety. Use the best GFIC outlets and switches possible ... don't skimp on cost just to save a few cents.
 
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Wow, I completely wasn't expecting so many replies so soon! I love IAP.

So to answer some questions: it's not my electrical circuits....I rewired the entire shop last summer and the circuits are fine....they are GFI but at the panel, and other things plugged into the same circuit work fine.

I took the brushes out and put them back in, they have that nice curved indentation and are far from being worn out...I haven't tried cleaning any other part of the motor, but from doing a 'look-see', there's no gunk anywhere...this motor is only about 8 months old.

I opened up the switch box and the fuse is not blown. There's no gunk on the switch terminals but I'll try cleaning them anyway....from everything you guys have said I suspect the switch has gone bad. I'm going to see if I can find the switch I pulled off the original delta motor and try that one. If not, I have an Ace hardware 5 minutes away, so a road trip may be in order!! I'll let you all know how it goes. *sigh*
 
My steel city lathe's switch is junk. Replaced it 2x already. So I just wired the lathe in the on position and bought one of those foot switches from HF. It works great and I can turn off the lathe w/o using my hands.
 
The reason I suggested moving OFF from a GFCI, is that when I first bought my Jet 1642, it would not work on a GFCI circuit -- plugged it into a non GFCI by recommendations by others, and have never had a problem since.
 
leehljp said:
Brian,
I have found that if I tap lightly on the box, it usually starts up. Once it begins to stop, I often have to tap it about every 3 to 10 minutes. Plum aggravating! I don't dare tap it hard, just jiggle it as though there is a loose connection.
Click to expand...

Brian,

While many of the reasons given sound good, I think it sounds more like the hamster is getting old and tired in that wheel. When he/she does, it just goes to sleep. When you tap lightly it wakes him/her back up and both the hamster and you are up and running. Tapping the case hard just makes them mad and they refuse to run.

Jerry
 
Same problem

I had the same problem with my PSI VS lathe. Sent the swith box back to them, replaced the switch. No problems since, unless of course, I dont over load the motor. Then I let it cool down a bit and it comes back to life.
 
Easy way to check out the switch.

Jump the wires giong into the switch and then plug the lathe into a power strip that has a switch on it. You can use the switch on the power strip to turn the lathe on and off. And don't forget that you have two power switches to check out. One is the originalDelta switch and the other is on the PSI VS controler.

For just a few dollars, you can avoid the problem altogether. Visit friendly electrical hardware source and purchase a 110V receptacle, a wall switch and a box to house them. Then get 5 or 6 feet of wire and a plug and then make up your own little extension cord with a switched receptacle on the end of it. (I always have a piece of wire with a plug on the end if it that I have salvaged from a dead electrical device of one sort or another. Be sure the wire is heavy enough to care the load of the lathe. I've got 3 or 4 extension cords I have rescued from the trash men that were run over by a lawnmower and set out by the curb.......recycle!!!)

If you don't have a piece of wire laying around, you can always buy some wire and a plug; but I have found it is usually cheaper to buy a made-up extension cord (10' is fine) and just cut off the female end.
 
OK folks, I too appreciate all of the answers and thanks Brian for bringing this up.

The reason I did not think it was the switch - is that on many occasions, I have toggled the switch up and down (on and off and on) and nothing happens; but when I tap the box lightly a couple of times, it usually comes on. And the reason I thought it was the rheostat is that sometimes it would slow down for a few seconds and speed back up on its own. That part does not sound like the switch.
 
Okay, I think I might have fixed the problem, are you all ready for this? The problem was sawdust! The PSI switch box itself is about 3" x 4", which was completely clear of dust. But when I took out the actual on/off switch and cracked it open, the thing was jammed full of dust, I guess from it being on my hands when I turn the lathe on and off?? I haven't tried running it for a substantial period of time yet, but after cleaning it and plugging it back in, the lathe fired up and worked like new. Who knew?
 
Are you talking about the switch on the PSI box or the original Delta switch??

Might be a good idea to get a piece of clear plastic from an empty food bag and tape it over the front of the switch to prevent a recurrence??
 
I took my switch apart (the PSI switch) and it was clean. Contacts were reasonable too. Slight pitting from use. So for me, there must be is something else that causes the momentary on/offs and slowdowns.

(For those with questions of my location: we have 100V 60 cycle but I have a heavy duty variac and keep the voltage set to 115. I have varied it on and off to see the voltage's effect. Since last fall, I have not varied it off of the 115V setting.)
 
WTG Brian,
Now plan on driving the car 45 mins North and lets cut some burl buddy! I'll stabilize a few you have while were cranking out some very nice blanks.
 
Randy_ said:
Are you talking about the switch on the PSI box or the original Delta switch??

Might be a good idea to get a piece of clear plastic from an empty food bag and tape it over the front of the switch to prevent a recurrence??
Click to expand...
This is the PSI switch I'm talking about. I don't know if it's even worth me taking any preventative measures. It's so easy for me to just pull it out and clean it once every couple of months. Remember, this is 9 months or so of buildup.
 
GouletPens said:
This is the PSI switch I'm talking about. I don't know if it's even worth me taking any preventative measures. It's so easy for me to just pull it out and clean it once every couple of months. Remember, this is 9 months or so of buildup.
Click to expand...

While this may be true, the added wear and tear of pulling it apart every so often will add up to a much shorter overall lifespan. I'd get a clear ballon and put it over the switch before reassembling and it should be sawdust tight.
 
I would put a cover over it because if that much sawdust is collecting you are inviting an opportunity for a fire with the saw dust and electricity being in such close contact. If one contact gets a little too hot you will have a fire on your hands. It could occur after you leave your shop. The risk, in my mind, is just not worth not taking the time to put a cover over it.
I have been running my lathe for over a year and when I recently took it apart to clean something else, there was no sawdust in it al all. This switch must not be very tightly put together.
 
The PSI switch box is on a cord so you can mount it almost anywhere, I ended up mounting it on the underside of my worktable, so that may be contributing to the sawdust buildup quite a bit. No doubt the dust that falls while I'm turning could creep its way in there, even though I use DC while turning. I think I might try moving the switch as well, or maybe even try a footpedal switch.
 
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