I have an 8 year old Shop Fox 40 inch lathe/mill combo. Obviously, it's a cheap import and has it's problems. Most of which I've been able to deal with.
However, the main lathe 1.5 HP 115V AC motor has been a real problem. It has both start and run capacitors (which I have replaced, without results) and a set of contacts that regularly stick. Right in the middle of a job, the motor will act up, ugh.
Since it's a reversible AC motor, it has a multi wire connection. Also, the space is tight, and the shaft looks to be 15/16", 0.940 or 24mm, (odd and not easy to find) I'm not 100% sure on the RPM, but I believe it to be an 1800RPM motor. It simply does not look fast enough to be a 3600RPM motor.
I had considered switching to a DC motor, with speed control, like the mini mill has. But, this would result in quite a bit of re-wiring and relay replacement.
I'd like to replace the motor with a quality one. Any suggestions?
Shop Fox Chinese lathe motor problem
Re: Shop Fox Chinese lathe motor problem
cujet,
Lathe data plate info, and motor data plate info would be
very helpful.
Nice clear photo's would also be helpful.
EDIT: Also it would be nice if you would put
your EARTHLY LOCATION in your profile so it
will show up under your name and to the left
of all your post's.
All these thing's mentioned make it much easier to
assist you with your problem.
Ken.
Lathe data plate info, and motor data plate info would be
very helpful.
Nice clear photo's would also be helpful.
EDIT: Also it would be nice if you would put
your EARTHLY LOCATION in your profile so it
will show up under your name and to the left
of all your post's.
All these thing's mentioned make it much easier to
assist you with your problem.
Ken.
Last edited by ken572 on Wed Jul 03, 2013 6:26 pm, edited 1 time in total.
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.
The best learning experiences come
from working with the older Masters.
Ken.
-
hammermill
- Posts: 2938
- Joined: Sun Jun 27, 2010 10:43 pm
- Location: pendleton or
Re: Shop Fox Chinese lathe motor problem
i would start by looking over the standard sizes
http://www.grainger.com/tps/motors_dayton_guide.pdf
http://www.grainger.com/tps/motors_dayton_guide.pdf
Re: Shop Fox Chinese lathe motor problem
I did this, of coursehammermill wrote:i would start by looking over the standard sizes
http://www.grainger.com/tps/motors_dayton_guide.pdf
. Nothing is exactly right. The shaft size and physical size are both problems, as there is little vertical clearance. When I get some time, I'll take a clear pic. It's a Shop Fox M1017
The more I think about it, the more I'd like to re-visit the idea of using a DC motor with speed control. That could make the lathe a much better toy.
Re: Shop Fox Chinese lathe motor problem
cujet,cujet wrote:I did this, of coursehammermill wrote:i would start by looking over the standard sizes
http://www.grainger.com/tps/motors_dayton_guide.pdf
It's a Shop Fox M1017
The more I think about it, the more I'd like to re-visit the idea of using a DC motor with speed control. That could make the lathe a much better toy.
Do you have the original Operator Manual and Parts Manual?
Ken.
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.
The best learning experiences come
from working with the older Masters.
Ken.
Re: Shop Fox Chinese lathe motor problem
cujet,
I would look for a plate or tag on the motor itself. In addition to the serial and model number, there should be a frame designator, something like a 56, 184, or 215, etc that may also have letters with it, like a 56C, or 215T, etc. These are NEMA standard sizes and designations. The numbers are the basic frame size (diametral), and the more powerful the motor, the longer it gets, but the end bells are the same specs. The letters generally indicate specific mounting features, like a "C" indicating a face mount, but also may indicate other things.
You don't specifically describe the problem, other than a switch that sticks, and that you have tried replacing the capacitors, but I must say that capacitor failure is down on the list of considerations unless the motor has been submerged or physically damaged. First and foremost would be the reversing switch, followed by the centrifugal start switch, flyweight assembly and springs, and internal insulation problems (pinching, overheating, short, open or ground.
Some of this can be diagnosed with minor observation. Take the cover off the reversing switch and note any evidence of arc damage on the contacts. Operating the switch and observing can expose poor contact performance, which can lead to poor motor performance. Listening for the distinctive "click" as the motor comes to a stop can reveal sticking centrifugal weights and sleeve, which can lead to motor start problems not electrically related to the motor. The electrical side of the start circuit, other than the reversing switch, is the domain of the start switch, which is actuated by the fiber washer on the sleeve of the centrifugal portion of the unit. If the start switch contacts are really fried they can sometimes be restored to service by careful dressing, being careful not to bend the springy portions of the switch, which can affect operation. Sometimes a good cleaning is all that is necessary. NO EMERY CLOTH!!! emery dust is conductive, and can lead to harmless, but exciting fireworks upon energizing.
When removing end bells, remember that the wiring is attached to the non-drive end and will have to be disconnected. Sometimes, removing the terminal board is all that is necessary. Note any odor of overheated varnish, as this may affect the insulation of the windings. Now is a good time for a "megger" test, and if you do not have access to such an instrument, take the center portion of the motor to a reliable shop, and ask them to perform it. It only takes a couple of minutes and is usually free if the fields are ready. "Ready" means end bells off, wiring disconnected except for terminal board and rotor out. You don't have to bring anything but the fields with you, in fact doing so may brand you as a "barefoot Pilgrim", ripe for a little sprinkle of bull. All they will have to do is clip one lead to the power in leads and another to the motor case and wind it up. No reading is good reading, as it is sensitive to millionths of an ohm.
Parts, if needed, may be another issue, but at least you'll know the score, and be an informed shopper
Good luck, PM if anything is not clear.
Bill Walck
I would look for a plate or tag on the motor itself. In addition to the serial and model number, there should be a frame designator, something like a 56, 184, or 215, etc that may also have letters with it, like a 56C, or 215T, etc. These are NEMA standard sizes and designations. The numbers are the basic frame size (diametral), and the more powerful the motor, the longer it gets, but the end bells are the same specs. The letters generally indicate specific mounting features, like a "C" indicating a face mount, but also may indicate other things.
You don't specifically describe the problem, other than a switch that sticks, and that you have tried replacing the capacitors, but I must say that capacitor failure is down on the list of considerations unless the motor has been submerged or physically damaged. First and foremost would be the reversing switch, followed by the centrifugal start switch, flyweight assembly and springs, and internal insulation problems (pinching, overheating, short, open or ground.
Some of this can be diagnosed with minor observation. Take the cover off the reversing switch and note any evidence of arc damage on the contacts. Operating the switch and observing can expose poor contact performance, which can lead to poor motor performance. Listening for the distinctive "click" as the motor comes to a stop can reveal sticking centrifugal weights and sleeve, which can lead to motor start problems not electrically related to the motor. The electrical side of the start circuit, other than the reversing switch, is the domain of the start switch, which is actuated by the fiber washer on the sleeve of the centrifugal portion of the unit. If the start switch contacts are really fried they can sometimes be restored to service by careful dressing, being careful not to bend the springy portions of the switch, which can affect operation. Sometimes a good cleaning is all that is necessary. NO EMERY CLOTH!!! emery dust is conductive, and can lead to harmless, but exciting fireworks upon energizing.
When removing end bells, remember that the wiring is attached to the non-drive end and will have to be disconnected. Sometimes, removing the terminal board is all that is necessary. Note any odor of overheated varnish, as this may affect the insulation of the windings. Now is a good time for a "megger" test, and if you do not have access to such an instrument, take the center portion of the motor to a reliable shop, and ask them to perform it. It only takes a couple of minutes and is usually free if the fields are ready. "Ready" means end bells off, wiring disconnected except for terminal board and rotor out. You don't have to bring anything but the fields with you, in fact doing so may brand you as a "barefoot Pilgrim", ripe for a little sprinkle of bull. All they will have to do is clip one lead to the power in leads and another to the motor case and wind it up. No reading is good reading, as it is sensitive to millionths of an ohm.
Parts, if needed, may be another issue, but at least you'll know the score, and be an informed shopper
Good luck, PM if anything is not clear.
Bill Walck
-
hammermill
- Posts: 2938
- Joined: Sun Jun 27, 2010 10:43 pm
- Location: pendleton or
Re: Shop Fox Chinese lathe motor problem
i doubt seriousely you will find a standart motor out of the box( except from the manf) but if you can find one that will work but needa a bigger shaft or differient mounting hole, that can be worked atound. many dc motors use the same frame sizes if they are nema frames like 56c the soup thickens when the manf has motors built to the spec they want to use. fasco and ge make lots of these. shaft and mount sizes will all be funny as may be the rpms and hp.
dc motor are another way to go but again it has to fit or better be made to fit. large tread mills are a good place to go to for scrounging. you need to know voltage,amperage, maybe hp ( it is often over rated)
PERMANT MAGNET motors will be small in size
dc motor are another way to go but again it has to fit or better be made to fit. large tread mills are a good place to go to for scrounging. you need to know voltage,amperage, maybe hp ( it is often over rated)
PERMANT MAGNET motors will be small in size
Re: Shop Fox Chinese lathe motor problem
Thanks for the great replies.
The internal start switch does stick. It's done so since new. Back then, I removed the end bell and cleaned the contacts. They continued to stick. So, I drilled a hole, where I can insert a plastic spray straw and "free" the contacts. It would work for a week or so, then stick again.
In the past, this worked well enough. But, now when the motor starts normally, it has an uneven, electrical grumbling sound. Like one winding is shorted or loose. The bearings are silky smooth. I suspect there is internal damage.
I've been looking for a data plate and do not see one. It could be located in an inaccessible area, or, I suspect it's nowhere to be found.
I may have to install a lower HP motor, as any of the 1.5HP motors I see are all considerably too big.
The internal start switch does stick. It's done so since new. Back then, I removed the end bell and cleaned the contacts. They continued to stick. So, I drilled a hole, where I can insert a plastic spray straw and "free" the contacts. It would work for a week or so, then stick again.
In the past, this worked well enough. But, now when the motor starts normally, it has an uneven, electrical grumbling sound. Like one winding is shorted or loose. The bearings are silky smooth. I suspect there is internal damage.
I've been looking for a data plate and do not see one. It could be located in an inaccessible area, or, I suspect it's nowhere to be found.
I may have to install a lower HP motor, as any of the 1.5HP motors I see are all considerably too big.
-
hammermill
- Posts: 2938
- Joined: Sun Jun 27, 2010 10:43 pm
- Location: pendleton or
Re: Shop Fox Chinese lathe motor problem
depending on many factors you may not notice a difference. many chinese motors name plate ratings are obtained at the instant of magic smoke release. called peak horsepower.
interesting they don,t show a manual on the web site for the manf
interesting they don,t show a manual on the web site for the manf
Re: Shop Fox Chinese lathe motor problem
cujet,
The grumbling sounds ominous. If this was a DC motor, an armature short would be the prime suspect, but AC motors have a laminated rotor that isn't subject to that kind of trouble. The only electrical components in the motor are the main windings, start windings, start switch and capacitors. There may also be a thermal overload switch that kills the motor if it gets too hot. The only parts of these that are not static are the start switch and thermal overload (if present). This leaves windings and capacitors. You say you have replaced the caps. so it is probably not them. Now we are down to windings and there are only three ways they fail, open, shorted, and grounded. The open is either a broken wire or a bad connection. Broken wire is a yes/no sort of failure, while bad connections can be detected with the aid of an AM radio, as they produce interference. Shorted windings can produce outright failure, if they are severe enough, but usually start out small and progress to failure due primarily to heat. The wire in the windings is not heavily insulated, using primarily varnish. The saving grace is that the difference in voltage is spread out over the entire length of the wire, and as the windings pile up, the voltage differential between any adjacent wires tends to be fairly small, and thus, the varnish is more than adequate under normal operating conditions. If you have a short between a couple of wires that are not too far apart from a voltage standpoint to trip a breaker, the resistance of that coil goes down, and since the voltage overall stays the same, the current goes up. Since the motor was designed for a certain amount of current and the wire size specified accordingly, the winding heats up, the varnish is further degraded from the heat and a cascading failure results. The primary indicators of this from a non invasive standpoint would be higher than normal current draw, detectible with an amprobe or other inductive ammeter, and hotter operation. Hotter is a relative term, as normally loaded, normally operating motors can get pretty hot and still be ok. However, if you take the load off the motor, run it and monitor the temperature with the back of the hand, it should not get more than nominally warm and not continue to get hotter. Usually five or ten minutes from a cold motor is sufficient. A grounded winding can be readily located with a "megger", as I previously stated, but you can also find them with a digital VOM or an amprobe with a voltage function. Just get a ground adapter down at the hardware store, plug your tool into it and plug that into the wall. Clip one wire of the VOM onto the ground tab on the adapter and the other onto a known ground, like the cover screw or adjacent ground pin in the other outlet. Should be negligible. It is possible that a VOM sufficiently sensitive, like a digital, may pick up induced voltage in the ground line that presents a false reading. Quickly shorting the ground tab to known ground will take this voltage away, and induced voltage will not immediately reappear when the jumper is removed, as will a grounded winding.
As Hammermill said, horsepower ratings are a big buzzphrase in the marketplace, some of which are truly outlandish, especially with vacuum cleaners and hand tools. There is a big difference between supplying useful work on an ongoing basis and the "magic smoke" method where you take voltage and amperage readings at, or very near, the failure point, calculate the wattage, convert that to "peak horsepower" and tout that as the ability to do anything for you.
Good Luck
Bill Walck
One final thought, if your local fire dep't has a thermal imaging camera see if you can get them to scan the motor after it has been running. Have another motor running for a reference and phrase the request along the lines of a "training" comparison. Sick motors light up a lot brighter than well ones and observing the comparison is actually quite helpful, especially in a paid dep't
The grumbling sounds ominous. If this was a DC motor, an armature short would be the prime suspect, but AC motors have a laminated rotor that isn't subject to that kind of trouble. The only electrical components in the motor are the main windings, start windings, start switch and capacitors. There may also be a thermal overload switch that kills the motor if it gets too hot. The only parts of these that are not static are the start switch and thermal overload (if present). This leaves windings and capacitors. You say you have replaced the caps. so it is probably not them. Now we are down to windings and there are only three ways they fail, open, shorted, and grounded. The open is either a broken wire or a bad connection. Broken wire is a yes/no sort of failure, while bad connections can be detected with the aid of an AM radio, as they produce interference. Shorted windings can produce outright failure, if they are severe enough, but usually start out small and progress to failure due primarily to heat. The wire in the windings is not heavily insulated, using primarily varnish. The saving grace is that the difference in voltage is spread out over the entire length of the wire, and as the windings pile up, the voltage differential between any adjacent wires tends to be fairly small, and thus, the varnish is more than adequate under normal operating conditions. If you have a short between a couple of wires that are not too far apart from a voltage standpoint to trip a breaker, the resistance of that coil goes down, and since the voltage overall stays the same, the current goes up. Since the motor was designed for a certain amount of current and the wire size specified accordingly, the winding heats up, the varnish is further degraded from the heat and a cascading failure results. The primary indicators of this from a non invasive standpoint would be higher than normal current draw, detectible with an amprobe or other inductive ammeter, and hotter operation. Hotter is a relative term, as normally loaded, normally operating motors can get pretty hot and still be ok. However, if you take the load off the motor, run it and monitor the temperature with the back of the hand, it should not get more than nominally warm and not continue to get hotter. Usually five or ten minutes from a cold motor is sufficient. A grounded winding can be readily located with a "megger", as I previously stated, but you can also find them with a digital VOM or an amprobe with a voltage function. Just get a ground adapter down at the hardware store, plug your tool into it and plug that into the wall. Clip one wire of the VOM onto the ground tab on the adapter and the other onto a known ground, like the cover screw or adjacent ground pin in the other outlet. Should be negligible. It is possible that a VOM sufficiently sensitive, like a digital, may pick up induced voltage in the ground line that presents a false reading. Quickly shorting the ground tab to known ground will take this voltage away, and induced voltage will not immediately reappear when the jumper is removed, as will a grounded winding.
As Hammermill said, horsepower ratings are a big buzzphrase in the marketplace, some of which are truly outlandish, especially with vacuum cleaners and hand tools. There is a big difference between supplying useful work on an ongoing basis and the "magic smoke" method where you take voltage and amperage readings at, or very near, the failure point, calculate the wattage, convert that to "peak horsepower" and tout that as the ability to do anything for you.
Good Luck
Bill Walck
One final thought, if your local fire dep't has a thermal imaging camera see if you can get them to scan the motor after it has been running. Have another motor running for a reference and phrase the request along the lines of a "training" comparison. Sick motors light up a lot brighter than well ones and observing the comparison is actually quite helpful, especially in a paid dep't
Re: Shop Fox Chinese lathe motor problem
You can see the hole I drilled to access the start contactor, ugh.
If I were to use a DC motor w/controller, where would I find a suitable motor and controller. I love the idea of variable speed.
Re: Shop Fox Chinese lathe motor problem
scmods,
Thanks for the great writeup and the superb troubleshooting tips. I do have access to a thermal camera, and being an aircraft mechanic, I have a megger. Never thought of using it on my Chinese motor.
I'll also try the AM radio, as that's very interesting. I like the way you think!!
Leaning towards installing a motor that fits, adapting the pulley and going on my way. To the best of my knowledge, I've never taxed this motor. Most of my work has been very light duty stuff.
Not really relevant, but here is a pic of my aircraft cylinder mounted in my lathe/mill and the first pass at making the exhaust port flat (a common procedure) came out great. I used an APEX screwdriver tip as the cutter. Worked perfectly and I ended up with a nice surface finish. (note: the exhaust gasket cuts into the aluminum and eventually won't seal due to the uneven surface)
Thanks for the great writeup and the superb troubleshooting tips. I do have access to a thermal camera, and being an aircraft mechanic, I have a megger. Never thought of using it on my Chinese motor.
I'll also try the AM radio, as that's very interesting. I like the way you think!!
Leaning towards installing a motor that fits, adapting the pulley and going on my way. To the best of my knowledge, I've never taxed this motor. Most of my work has been very light duty stuff.
Not really relevant, but here is a pic of my aircraft cylinder mounted in my lathe/mill and the first pass at making the exhaust port flat (a common procedure) came out great. I used an APEX screwdriver tip as the cutter. Worked perfectly and I ended up with a nice surface finish. (note: the exhaust gasket cuts into the aluminum and eventually won't seal due to the uneven surface)