PM-1236T on VFD

[dfwilbanks]

Is anyone running a 3 phase PM-1236T or PM- 935TS on a VFD? Do you leave the belt/speed setup in one position and use the VFD to control speed? (what setup) Or, do you set the VFD to 60 Hz and select the speed in the normal fashion? (I guess that option would be a little silly with a VFD)

I'm planning to connect my PM-1236T and PM- 935TS to one VFD for now (cause that's all I have) with a 3 position 3 phase switch. If the occasion arises where I need both machines at the same time I'll get another VFD.

That occasion may arises sooner than later because when the little woman ask what the lathe does I told her it peals potatoes, and the mill, it's a big mash potatoe mixer. I'm sure she will want to give it a go sometime.

 

[kb58]

You're just going to get a lot of different opinions.

I have a 935 and very rarely change the pulley, changing speed almost exclusively with the VFD. Almost. If you use it every day to do different stuff, no doubt you'll be changing the pulley as well. All depends on what you're doing.

 

[dfwilbanks]

I have a 935 and very rarely change the pulley, changing speed almost exclusively with the VFD.

That's what I would like to do. But tell me what pully position you use most of the time and what speed ranges it gives you. I could do the experiments myself (my 935 has no power yet) but the reason I like this venue is that someone has already done it.

I kinda like all the different opinions.

 

[Bob Korves]

Running more than one machine on a VFD can be death to the VFD. Makers and sellers of VFDs specify that the VFD be hard wired to the motor, with no switches or disconnects between the VFD and the motor. I am not saying it is impossible to do so, but you had better make sure that the VFD and the motor are properly hooked up each and every time the VFD is turned on, or you may let the magic smoke out of it. I follow their advice, and have had no problems.

 

[wrmiller]

The belt on my 935 spends most of it's time in the next-to-highest pulley (speed-wise). Or one pulley up from the bottom. Depending on your perspective.

I will drop the belt to the next slowest pulley when I'm using larger drill bits, or I'll use the highest speed pulley when I'm running real small end mills. Neither of these scenarios happens all that often though.

 

[dfwilbanks]

Running more than one machine on a VFD can be death to the VFD. Makers and sellers of VFDs specify that the VFD be hard wired to the motor, with no switches or disconnects between the VFD and the motor. I am not saying it is impossible to do so, but you had better make sure that the VFD and the motor are properly hooked up each and every time the VFD is turned on, or you may let the magic smoke out of it. I follow their advice, and have had no problems.

Hey Bob, I enjoy your comments. I wish however that I could agree with one. LOL

I know of no machine, other then my little Chinese CNC router, where the VFD connects directly to the motor. My Lathe, Mill, Drill Press, anything that may use a VFD has a power switch between the VFD and the motor. That power switch is off when the machine is not being used. So, I turn on the VFD, turn my selector switch to the machine I want to use, go to that machine and turn it on. No Magic Smoke released. In fact I cannot think of any scenario where the VFD would be unhappy. If anyone sees one please tell me. I really can't afford to damage my VFD over something I missed.

This assumes that the two motors will work with the same VFD settings such as max frequency and the VFD is capable of running the motors.

 

[81husky]

I know of no machine, other then my little Chinese CNC router, where the VFD connects directly to the motor.

I have a 1340GT and 935TS that have the VFD wired directly to the motor. Of course I did all the wiring myself. In all of my research and reading of the VFD instructions, that is the only way I was lead to believe would work satisfactorily. If you've had success with switches and such in between, you may be just fine. Personally, from what I've read, I didn't take the chance. Two machines, two VFD's. Good luck, and I don't mean that in any snarky way at all.

 

[mksj]

The main problem arise when you use a switch when the motor is running, just having the switch there and selecting the motor is not an issue if it is not running. I have done something similar to this on a 2 speed motor to select either 4 pole or 8 pole, it was a 3 way switch so the neutral position discontinued the run commands. The VFD was programmed for motor 1 and motor 2, the settings were changed with the selector switch. It also depends on if the VFD is setup for V/Hz vs. sensorless vector, the latter uses feedback from the motor windings to determine rotor rpm. Still, most VFD manuals indicate a direct connection to the motor, with a few exceptions.

Using a single VFD in this situation is risky, the motor properties are not the same, the parameters would be different for a mill vs. a lathe, often the logic inputs are also set up differently as well as other parameters. If you run autotune, they will load different parameters and what works well for one motor may be poor for the other. It is possible to setup two sets of operating parameters on some VFDs, but it becomes complicated if you want either machine to operate properly. Something like an E-Stop does no good if it is on the other machine or VFD cabinet when you are running the other machine.

At the cost of VFDs these days, my recommendation would be to use a VFD per machine, you can save some money on the mill with a simpler VFD/setup. This way the machines will operate correctly and safely. I have outlined a simple basic VFD install for the 1236/1340GT which uses the existing contactors and can be done with minimal cost. The lathe VFD should have a braking resistor to aid in quick stopping, I would not omit the external resistor nor buy a VFD that did not support it. On the mill, many people have gone with the Teco L510, there are other reasonably priced VFDs and suggested connection diagrams using 3 wire control for the WJ200. This affords additional safety when using the mill. Just because it can be done and appears to work does not indicate that it is correct nor safest approach.

 

[dfwilbanks]

I have a 1340GT and 935TS that have the VFD wired directly to the motor. Of course I did all the wiring myself. In all of my research and reading of the VFD instructions, that is the only way I was lead to believe would work satisfactorily. If you've had success with switches and such in between, you may be just fine. Personally, from what I've read, I didn't take the chance. Two machines, two VFD's. Good luck, and I don't mean that in any snarky way at all.

Thanks

 

[dfwilbanks]

The main problem arise when you use a switch when the motor is running, just having the switch there and selecting the motor is not an issue if it is not running. I have done something similar to this on a 2 speed motor to select either 4 pole or 8 pole, it was a 3 way switch so the neutral position discontinued the run commands. The VFD was programmed for motor 1 and motor 2, the settings were changed with the selector switch. It also depends on if the VFD is setup for V/Hz vs. sensorless vector, the latter uses feedback from the motor windings to determine rotor rpm. Still, most VFD manuals indicate a direct connection to the motor, with a few exceptions.

Using a single VFD in this situation is risky, the motor properties are not the same, the parameters would be different for a mill vs. a lathe, often the logic inputs are also set up differently as well as other parameters. If you run autotune, they will load different parameters and what works well for one motor may be poor for the other. It is possible to setup two sets of operating parameters on some VFDs, but it becomes complicated if you want either machine to operate properly. Something like an E-Stop does no good if it is on the other machine or VFD cabinet when you are running the other machine.

At the cost of VFDs these days, my recommendation would be to use a VFD per machine, you can save some money on the mill with a simpler VFD/setup. This way the machines will operate correctly and safely. I have outlined a simple basic VFD install for the 1236/1340GT which uses the existing contactors and can be done with minimal cost. The lathe VFD should have a braking resistor to aid in quick stopping, I would not omit the external resistor nor buy a VFD that did not support it. On the mill, many people have gone with the Teco L510, there are other reasonably priced VFDs and suggested connection diagrams using 3 wire control for the WJ200. This affords additional safety when using the mill. Just because it can be done and appears to work does not indicate that it is correct nor safest approach.

I have a VFD that I like. Rated at 16A output, 4kw, 5hp. I have been actively looking for another one like it. It's a Sunfar (Simphoenix) E550-2S0040B. Any help in locating one will be appreciated. I think I said somewhere above that this is temporary, maybe I just imply it. It has breaking resistor terminals (the B in the model number) and I have the resistors.

I want to get up and running while I look for another E550 VFD. So I have a 2hp and 3hp motor the by the same manufacturer. I absolutely disagree that tbe VFD settings would be different between a lathe and mill. Very few parameters need to be changed from default. The ones that could change would be the same for both machines in my case. As for e-stop it is quite easy to connect as many N.O. switches as you want in parallel and stop whatever machine is connected to the VFD. The lathe has a e-stop button that is not connected to the VFD. I may or may not install one on the mill.

I challenge anyone to so me data, or even a manual entry, that states the motor has to be connected directly to the VFD. Please, don't post those little rudimentary connection diagrams as proof. Those show one posibility and not all posibilites.

I'm not advocating connection two very dissimilar motors to a VFD. They must be capable of operating normally with the same VFD setup.