[How do I?] Late model 10L with two speed motor won't start again after stop. Dead.

Well, update time already.
I worked with more 2 inch stainless 420 for a few hours this afternoon. I was polishing the part, maybe taxing the motor more than just cutting. I checked the spindle that it wasn't too warm. I noticed that the area around the belt was warm, not just the bearings.
The motor was too hot too touch. I know motors can operate at different temperatures than humans, but I suspect this. I was just about to finish for the night, so I did not take the time to open the panel again to check the contactors again. I am thinking when I let the motor cool, and if I close and let the contactors snap open again a few times, it will reset.
I will let you know tomorrow

Bernie
 
Well, update time already.
I worked with more 2 inch stainless 420 for a few hours this afternoon. I was polishing the part, maybe taxing the motor more than just cutting. I checked the spindle that it wasn't too warm. I noticed that the area around the belt was warm, not just the bearings.
The motor was too hot too touch. I know motors can operate at different temperatures than humans, but I suspect this. I was just about to finish for the night, so I did not take the time to open the panel again to check the contactors again. I am thinking when I let the motor cool, and if I close and let the contactors snap open again a few times, it will reset.
I will let you know tomorrow

Bernie
 
Ok.
I am glad I tightened wires etc the other day, but I am now pretty positive that my motor is overheating while in "Fast" (High). Then there is some "smart" circuit or mechanism that is disconnecting the switch "On" circuit, but was allowing the "Stay On" circuit to keep going DURING my cuts. This is probably why the machine has never stopped during a cut.
Now to figure out why the hell the motor is overheating so easily. I don't know if I am just underestimating how much I am working the lathe, or how much work I think it should be capable of. It even has this problem when I had a fan running in the motor compartment!
Anyone have any thoughts on why a motor that does not appear, to me, to be "shorting out" could be overheating enough to give me these problems? Or is the problem in a different part of the contactor circuit?

Thanks folks

Bernie
 
Anyone have any guesses or opinions on why my motor might be running hot? Or if there is a possible problem in the contactors that is overheating or overdrawing a different way?
I am not in a great place to buy a new motor right now if it isn't necessary

Bernie
 
Bernie,
you may shut your power off and check the heaters to see if one is not reseting completely. also check the heater numbers to see if they are the correct number . all should be the same number. sometimes the push resets don't work to completely reset properly. look to see if it manually resets the trip good when you push it in. I think somewhere on your motor or contactor cover says the heater number range to use. they aren't that expensive to replace. another thing you can check if you have a laser heat sense gun are all the wire connections and components for any hotter areas when system is under load. this will show poor or loose connections. just aim the laser spot on all areas and you can also point it at your motor to see if bearings are overheating. HF sells the laser heat guns and they are very handy to have. they can find heat problems on machines and
wheel bearings without burning your fingers. I used them on power pannels to locate loose wires or problem breakers. loose connections are always hotter than normal. maybe a friend has one you could borrow. whatever-- be safe and hope you locate your problem.
Dave
 
Dave Smith said:
Bernie,
you may shut your power off and check the heaters to see if one is not reseting completely. also check the heater numbers to see if they are the correct number . all should be the same number. sometimes the push resets don't work to completely reset properly. look to see if it manually resets the trip good when you push it in. I think somewhere on your motor or contactor cover says the heater number range to use. they aren't that expensive to replace. another thing you can check if you have a laser heat sense gun are all the wire connections and components for any hotter areas when system is under load. this will show poor or loose connections. just aim the laser spot on all areas and you can also point it at your motor to see if bearings are overheating. HF sells the laser heat guns and they are very handy to have. they can find heat problems on machines and
wheel bearings without burning your fingers. I used them on power pannels to locate loose wires or problem breakers. loose connections are always hotter than normal. maybe a friend has one you could borrow. whatever-- be safe and hope you locate your problem.
Dave
Click to expand...
Thanks Dave

I am actually going to go all out and borrow my friend's Flir temperature camera attachment for my phone. BUT I need to "out" myself for being a complete dork, before I take any readings.
Without even measuring the amperage into the machine, or taking temperature readings, I think I may have isolated a big part of the problem. After taking a few measurements of various chips I was making, and performing a few calculations, I am pretty confident I have been taking 2-to-4hp cuts with my 1hp lathe. Big shocker that this might heat up the motor, and possibly the contactors.

I used a Kennametal cutting forces web page to determine the approximate HP required at the motor. There are pop-ups next to some of the fields on the page, but with a few minutes of googling and measuring, I could add in approximate factors for:
-approximate Brinell hardness
-the "Power Constant," often seen as "hp/in^3/min," for material I was cutting (stainless steel which plugs in as .73)
-approximate "machine efficiency," which is quite high since this is a direct belt drive machine, as opposed to geared head or hydraulic drive

Cutting Force Calculator | Turning – Kennametal

Cutting Forces, Torque, and Horsepower for Turning Applications
www.kennametal.com www.kennametal.com

Besides making my cuts fewer cubic inches per min (in^3/min), there are definitely some other factors I can experiment with to reduce the hp/amps I am putting this motor through.
I will definitely be updating this thread further.

Bernie
 
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