3PH motor wiring

[Karl_T]

I honestly can't see a 12" gear head lathe of that style being able to use more than 1hp. My 14" Logan is a far more massively built lathe which can take some seriously heavy cuts and it doesn't come close to slowing down a 2hp motor.

I think this bigger motor is a great idea, if he can fit it to the machine. Now no/less need to change gearing speeds, just use the VFD to quickly get the right speed. Remember if you run the 3hp motor at 20hz, its now a 1 hp motor.

 

[Harry Knutz]

Well I did,lol

On another forum, I had a guy think it was my real name!

 

[Ultradog MN]

I honestly can't see a 12" gear head lathe of that style being able to use more than 1hp. My 14" Logan is a far more massively built lathe which can take some seriously heavy cuts and it doesn't come close to slowing down a 2hp motor.

My 14.5" lathe has a 5 hp.
Pretty sure it's original...

 

[G-ManBart]

My 14.5" lathe has a 5 hp.
Pretty sure it's original...

Okay, but that's a different topic....a bigger machine with more HP.

I was referencing a bigger machine with less HP than what the OP is talking about as a comparison.

PM puts a 1.5hp motor on their most expensive 12" lathe. Eisen puts a 1.5hp motor on their most expensive 12" lathe. I can't imagine those machines being rigid enough to take advantage of twice as much power. I wasn't saying it would hurt anything, just that I think it's unlikely the OP's machine can come close to using that much power. I guess, in theory, it's possible to start damaging stuff with too much power, but that would entail some pretty reckless operation.

 

[Pevehouse]

Okay, but that's a different topic....a bigger machine with more HP.

I was referencing a bigger machine with less HP than what the OP is talking about as a comparison.

PM puts a 1.5hp motor on their most expensive 12" lathe. Eisen puts a 1.5hp motor on their most expensive 12" lathe. I can't imagine those machines being rigid enough to take advantage of twice as much power. I wasn't saying it would hurt anything, just that I think it's unlikely the OP's machine can come close to using that much power. I guess, in theory, it's possible to start damaging stuff with too much power, but that would entail some pretty reckless operation.

Yea, I don’t really get reckless with it. I tend to over build everything I do so this is no different. The machine I have is pretty ridvged for a 12” lathe and the added weight of the bigger motor should make it a little heftier. I do understand what you are saying but I’m gonna go with it. So I have more power and torque than the machine actually needs. Doesn’t mean I got to spin the jaws out of the chuck. I have a mini lathe/ mill combo that came with 2 hp motors from the factory. Absolutely unnecessary but that what they did,lol

 

[Pevehouse]

I think this bigger motor is a great idea, if he can fit it to the machine. Now no/less need to change gearing speeds, just use the VFD to quickly get the right speed. Remember if you run the 3hp motor at 20hz, it’s now a 1 hp motor.

I see what you mean on the frequency. So I need to use the VFD to get my speed right?

 

[G-ManBart]

Yea, I don’t really get reckless with it. I tend to over build everything I do so this is no different. The machine I have is pretty ridvged for a 12” lathe and the added weight of the bigger motor should make it a little heftier. I do understand what you are saying but I’m gonna go with it. So I have more power and torque than the machine actually needs. Doesn’t mean I got to spin the jaws out of the chuck. I have a mini lathe/ mill combo that came with 2 hp motors from the factory. Absolutely unnecessary but that what they did,lol

I wasn't saying don't do it, I was just saying it's just way more power than the machine can actually use. Clearly there was something wrong with the previous motor from your description of what it was doing, so replacing it makes sense. I'd be surprised if the new motor uses the same size shaft as the previous motor going from 1 to 3hp, which might mean a pulley swap.

 

[Karl_T]

I see what you mean on the frequency. So I need to use the VFD to get my speed right?

I used geared lathes for 20 years. One always leaves it at the speed its running, too much work to change the speed. With variable speed knob, just tweak it as the machine runs. I even speed the machine on facing cuts, speed it up as diameter gets smaller. Really helps on cutoff.

You likely can just leave your lathe set in the second to top gear for almost everything. If doing something like a 2" acme screw thread, drop to lowest gear.

Once you get used to it, its hard to ever go back. I even installed VFDs on mills with reeves variable speed, its SOOO nice to just quickly set speed as it runs.

 

[Pevehouse]

I wasn't saying don't do it, I was just saying it's just way more power than the machine can actually use. Clearly there was something wrong with the previous motor from your description of what it was doing, so replacing it makes sense. I'd be surprised if the new motor uses the same size shaft as the previous motor going from 1 to 3hp, which might mean a pulley swap.

Surprisingly enough they are the same size. I was a little concerned about that at first too

 

[Pevehouse]

I used geared lathes for 20 years. One always leaves it at the speed its running, too much work to change the speed. With variable speed knob, just tweak it as the machine runs. I even speed the machine on facing cuts, speed it up as diameter gets smaller. Really helps on cutoff.

You likely can just leave your lathe set in the second to top gear for almost everything. If doing something like a 2" acme screw thread, drop to lowest gear.

Once you get used to it, its hard to ever go back. I even installed VFDs on mills with reeves variable speed, its SOOO nice to just quickly set speed as it runs.

I do the same. Got mine set up remotely on a potentiometers