VFD for Clausing 5419

[Vince]

VFD for Clausing 5429

I'm thinking about up grading my Clausing lathe with a VFD. This machine is about 50 years old and still has the original motor on it.
This machine is already a variable speed from the factory using a variable belt sheave.
I was wondering if I would be better off just installing an optical sensor to monitor spindle RPM or go ahead and install a VFD which means I will probably have to change the motor and add a cooling fan. If I go with the later I would probably do away with the variable sheave and add a braking resistor.
I am also looking to buy a new lathe but I think I would keep the Clausing to do my 5C work. Or, I could sell the Clausing and use the money to get a 5C setup and a 6 jaw chuck for the new lathe.
Any opinions?

Thanks, Vince

 

[JimDawson]

I might have a few thoughts to help you through your thought process.

The insulation in the old motor might not like the spikey output from the VFD, it may not live too long under those conditions.

If your variable speed is working OK, then putting a speed monitor on the existing system is a reasonable option.

Even if you decide to go with a new motor and a VFD, I would leave the variable speed hardware in place so that you can keep the motor RPM, and thus the HP up in the normal operation range. If you need to know the spindle RPM, then you would still need a speed sensor.

As far as selling the Clausing or keeping it :thinking: There times that I wish I had a second lathe, even if just for secondary operations. It might speed up the production on some jobs. If you have the room, and you don't really need to sell it to tool up your new lathe, then I guess I would keep it. At least for a while, to see if you really need it or not.

 

[John Hasler]

What usually kills old motors is heat, not voltage. They don't usually have the class F or H insulation used in newer VFD-rated motors. When you slow them down the internal fan doesn't move much air. I think I'd add a fan to any motor I put VFD on, perhaps with a relay connected to the VFD so that it only ran at low speeds.

 

[Vince]

Re: VFD for Clausing 5429

I might have a few thoughts to help you through your thought process.

The insulation in the old motor might not like the spikey output from the VFD, it may not live too long under those conditions.

If your variable speed is working OK, then putting a speed monitor on the existing system is a reasonable option.

Even if you decide to go with a new motor and a VFD, I would leave the variable speed hardware in place so that you can keep the motor RPM, and thus the HP up in the normal operation range. If you need to know the spindle RPM, then you would still need a speed sensor.

As far as selling the Clausing or keeping it :thinking: There times that I wish I had a second lathe, even if just for secondary operations. It might speed up the production on some jobs. If you have the room, and you don't really need to sell it to tool up your new lathe, then I guess I would keep it. At least for a while, to see if you really need it or not.

I have thought about keeping the Clausing for second operations, my problem with that is I will have to either move a drill press and/or my compressor to my larger shop. Not really a big deal but both shops are about filled to capacity. I need to sell a table saw and a radial arm saw and that would open up some space. I have over 2500 SF between both shops and have managed to fill them both. Go figure. A friend said I should add on but I can see that would be a bad move because then I would acquire more stuff.
If I do keep the lathe I think I will install a tach feed for sure.

 

[JR49]

What usually kills old motors is heat, not voltage. They don't usually have the class F or H insulation used in newer VFD-rated motors. When you slow them down the internal fan doesn't move much air. I think I'd add a fan to any motor I put VFD on, perhaps with a relay connected to the VFD so that it only ran at low speeds.

I'm reading this with interest. I just put a VFD on my 3 phase logan which has variable speed drive. Like yours, it also has a 50 year old motor. but I'm planning on using the VFD only to convert single to 3 phase and keep the motor turning at full RPM's, using the drive to adjust speeds. Hopefully, this will allow the motor to survive with the VFD. Any thoughts? JR49

 

[Vince]

I'm reading this with interest. I just put a VFD on my 3 phase logan which has variable speed drive. Like yours, it also has a 50 year old motor. but I'm planning on using the VFD only to convert single to 3 phase and keep the motor turning at full RPM's, using the drive to adjust speeds. Hopefully, this will allow the motor to survive with the VFD. Any thoughts? JR49

As long as your not adjusting the output frequency of the drive below 60 hz you should be fine.