Jet 1236P

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pete
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Re: Jet 1236P

Post by pete »

I won't say 3 hp is too much on that 12 x 36 lathe. 2 hp would probably still be enough. But the extra will come in handy when your adjusting the VFD to operate the motor into a lower rpm, lower torque situation. However with my mill, I made my own personal choice that if I need below about 40-45 hz I take the time to drop the speed mechanically with it's own belt drive. That keeps the motor a bit happier and running in it's rough design range. Going below that for anything more than a minute or two is being lazy. I can swap belt positions in easily under a minute. With a lathe, lower rpms mean larger part diameters in most cases. And those larger diameters are exactly where the high torque is needed. A VFD controlled motor can only be expected to do so much. As Bill mentioned earlier, that mechanical part of the drive is still very much required. I use the same as what your planning on doing, a 220V single ph line to a 220V input to the VFD that then has the required 220V 3 ph output to the motor. There is NO comparison between a set up like this and any single ph motor I've ever used. The difference was to me completely amazing the very first time I started it up. Within 30 seconds I was instantly hooked on VFD's and 3 ph motors on any machine tool.

I've not used them yet, most forum posts seem to be without complaints about the company or there products. https://www.automationdirect.com/adc/home/home Depending on your budget you might find everything your going to need in that link.
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Bill Shields
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Re: Jet 1236P

Post by Bill Shields »

good luck getting a 3 hp motor to fit in the space that I believe is available....

I get a lot of stuff from automation direct
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Bill Shields
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Re: Jet 1236P

Post by Bill Shields »

In reality.. a 1 hp motor with back gear running will snap off any tool it that lathe will hold
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Bill Shields
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Re: Jet 1236P

Post by Bill Shields »

I use Westinghouse TECO units...more because I am used to them than any specific tech spec. They seem to be reasonably reliable and available from many locations (or used to be)
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pete
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Re: Jet 1236P

Post by pete »

Yep I hadn't thought about the available room and assumed Randydan had already checked that Bill. If he hasn't then he'd better do so before deciding on any motor. And again true about that back gear. Without it and the standard pulley ratios, the extra torque might be handy. Maybe not enough to justify the extra VFD and motor costs to go larger even if it will fit.
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Bill Shields
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Re: Jet 1236P

Post by Bill Shields »

I am always amazed at people who think that they can just slap a VFD on a lathe, get full torque out of the motor at low speed and think that they can abandon all of the intrinsic gearing that every engine lathe needs.

What is the torque multiplication ratio on back gear of a 12" lathe....30:1?

Ok...a watch maker's lathe...maybe you can get away with it :mrgreen:
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Randydan
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Re: Jet 1236P

Post by Randydan »

The motor that came with the lathe is not going to work at all, it has to go, and F/N/S switch is toast which actually looks like a furnas A14. I have a source for inverter 3 phase motors that are cheap. I was searching around for replacement motors and found a few people that had switched over to VFD and said they were really happy. Also, I came up with a 3hp from a post I had seen somewhere, but it could have been for a different Jet lathe. Yes, the 3hp is too big to fit in there. But I'm still comparing and researching for a motor and haven't totally made a hard decision yet.

But thank you for all of your input, I really appreciate it. Every bit of info helps tremendously. I will post some pics this weekend, I would have done it sooner, but it's been a busy week.
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Steggy
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Re: Jet 1236P

Post by Steggy »

Randydan wrote: Sat Feb 05, 2022 1:01 am The motor that came with the lathe is not going to work at all, it has to go, and F/N/S switch is toast which actually looks like a furnas A14. I have a source for inverter 3 phase motors that are cheap. I was searching around for replacement motors and found a few people that had switched over to VFD and said they were really happy. Also, I came up with a 3hp from a post I had seen somewhere, but it could have been for a different Jet lathe. Yes, the 3hp is too big to fit in there. But I'm still comparing and researching for a motor and haven't totally made a hard decision yet.

But thank you for all of your input, I really appreciate it. Every bit of info helps tremendously. I will post some pics this weekend, I would have done it sooner, but it's been a busy week.

A 2 HP, frame 145 motor is more than adequate for that lathe, and will fit in the available space if the wiring box is at the fan end of the motor. That's the setup I have on my 1236PS and it works just fine. 3 HP, in my opinion, is overkill for this lathe.
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Bill Shields
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Re: Jet 1236P

Post by Bill Shields »

A been there done that caution on cheap 3 ph motors and low speed cogging and overheating.
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Randydan
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Re: Jet 1236P

Post by Randydan »

BigDumbDinosaur wrote: Sat Feb 05, 2022 2:21 am
Randydan wrote: Sat Feb 05, 2022 1:01 am The motor that came with the lathe is not going to work at all, it has to go, and F/N/S switch is toast which actually looks like a furnas A14. I have a source for inverter 3 phase motors that are cheap. I was searching around for replacement motors and found a few people that had switched over to VFD and said they were really happy. Also, I came up with a 3hp from a post I had seen somewhere, but it could have been for a different Jet lathe. Yes, the 3hp is too big to fit in there. But I'm still comparing and researching for a motor and haven't totally made a hard decision yet.

But thank you for all of your input, I really appreciate it. Every bit of info helps tremendously. I will post some pics this weekend, I would have done it sooner, but it's been a busy week.

A 2 HP, frame 145 motor is more than adequate for that lathe, and will fit in the available space if the wiring box is at the fan end of the motor. That's the setup I have on my 1236PS and it works just fine. 3 HP, in my opinion, is overkill for this lathe.

'Dinosaur' Thank you very much for the motor info. I'm sure you spent hours searching motor and frame sizes. I really appreciate that, that is a big help. I found some of your posts on the lathe and read about what you did for the pulleys. Also, nice write up.

Thanks again
Randydan
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Re: Jet 1236P

Post by Randydan »

Bill Shields wrote: Sat Feb 05, 2022 7:38 am A been there done that caution on cheap 3 ph motors and low speed cogging and overheating.

Bill, I'm sorry my post was not real clear. I have a relative who has an electrical repair shop. He will help me out on pricing on the motor and the components. But I'm trying to do all of the leg work. He has enough work to do with his business. Hope that makes more sense. We actually do some bartering from time to time. So it works out both ways.

But I fully understand on going cheap on things. I have been there done that. More times that I want to admit. You would think by now I would have learned. Ha Ha

But thanks anyway.
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Bill Shields
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Re: Jet 1236P

Post by Bill Shields »

Good deal to be had by all.

One thing that I have learned is that a vector drive...that gives feedback to the VFD so that it knows motor rpm as well as current load...can be very helpful on a lathe there consistent surface finish is desired.
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