Need info on VFD

I agree with Jim in this case for several reasons, but with one caveat. Using the same VFD for both machines using the same parameters is not a good choice. What can be done is some VFDs allow you to setup two separate parameter files, one for each motor, you can switch the motor parameter files based on a programmed input. You cannot use the machine motor switch/contactors to control the VFD output, you need to program the VFD low voltage inputs for the VFD run commands. Since the run commands and mode of operation would be different between the lathe and the mill, it can get messy quickly. At the end of the day if this is a long term replacement you would be better off using a dedicated VFD for each machine.
I have a couple questions. I set my perameter for what I had found best lathe 8 second ramp and a 3 second deceleration. Will this adversely effect my mill? I typically only adjust the frequency when threading to a shoulder would there be any issues with that? Also on my gs2 I have just use the two wire forward and reverse using a 24v DI for the forward command and the same for the reverse. I’m breaking the common for my E-stop. Most my day to day drive experiences are 1500HP ABB and Siemens VFDs. My big motors are 2000HP traction motors driven with SCRs. I’ve not had any issues with my current set up just kinda worried now. I never run my mill at less than 60hz the motor on it is not drive rated. I just don’t want the ramp and deceleration to crater my mill.
 
I have a couple questions. I set my perameter for what I had found best lathe 8 second ramp and a 3 second deceleration. Will this adversely effect my mill?

It might be a bit slow for the mill, but won't hurt anything. I think I have mine set at 3 and 3. You just have to think ahead a bit when power tapping on the mill.

I typically only adjust the frequency when threading to a shoulder would there be any issues with that? Also on my gs2 I have just use the two wire forward and reverse using a 24v DI for the forward command and the same for the reverse. I’m breaking the common for my E-stop.

That's the way I do my E-stop on both the mill & lathe

Most my day to day drive experiences are 1500HP ABB and Siemens VFDs. My big motors are 2000HP traction motors driven with SCRs. I’ve not had any issues with my current set up just kinda worried now.

Mmmm Yeah, that's big :)

I never run my mill at less than 60hz the motor on it is not drive rated. I just don’t want the ramp and deceleration to crater my mill.

I don't think it will be a problem.
 
I have a couple questions. I set my perameter for what I had found best lathe 8 second ramp and a 3 second deceleration. Will this adversely effect my mill? I typically only adjust the frequency when threading to a shoulder would there be any issues with that? Also on my gs2 I have just use the two wire forward and reverse using a 24v DI for the forward command and the same for the reverse. I’m breaking the common for my E-stop. Most my day to day drive experiences are 1500HP ABB and Siemens VFDs. My big motors are 2000HP traction motors driven with SCRs. I’ve not had any issues with my current set up just kinda worried now. I never run my mill at less than 60hz the motor on it is not drive rated. I just don’t want the ramp and deceleration to crater my mill.

Your ramp times should not be an issue. The lower frequencies generate heat with less motor motion to cool, but for such short times, it really doesn't matter. You also are not pulling load while turning the spindle on, so even better. The ramp down time adds heat back into the VFD. If you try to stop too fast, you will fault the VFD. To remedy this you can add a braking resistor. I would think you should be able to be a lot more aggressive with your ramp times.
 
Thanks Jim and macardoso. I really didn’t figure it would be a problem. I was kinda wondering mksj take on why sharing a drive would be a bad thing
 
Typically for *best* performance, a VFD needs an intimate knowledge of the motor and load it is driving. If you have 2 identical motors, switching between them shouldn't be an issue. The issue comes when the drive is shared between dissimilar motors as the cornering frequency, slip speed, and motor inductance can vary greatly. What this can result in is higher heat generation, poor speed control, and incorrect application of control strategies. Some drives allow you to save configurations for multiple motors (you may be familiar with this from the AB PowerFlex drives) and load them as needed. Another option is to wire the motors in parallel and tune the drive for the combined motor load, but this probably won't work well as your lathe would turn on when you started the mill.
 
Waiting on 2 100Mfd run capacitors to complete my RPC. Tried using the Fitch plans but couldn't follow the schematic so I noodled out my own. Would appreciate any input you folks may have before I apply power to the unit. Would hate to let the magic smoke out. LOL
 

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It looks like it will work, myself I probably would have used one double pole start button rather than two separate start buttons
mark
Question: are you rebuilding your existing unit from scratch using the original motor?
 
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For markba663csi, I am rebuilding my original unit using the original motor. The motor shop checked it and proclaimed it as good. When I picked it up they ran it for me however they had it wiried differently than I had it wired. They had it wired star/delta, meaning it would start as wye/star then run as delta. It is a 12 wire motor and can be run on either 230 or 460 power. The reason I didn't use a double pole switch is that I was afraid the start capacitor would stay energized after the motor was started.. I hooked it up today but couldn't get it to run. It kept tripping the main breaker. Am going to have a friend, who is an electrician, look it over and see if he can figure out where I screwed up.

For JimDawson, I didn't think there would be that much load on the start capacitor as it was only going to be energized for a few seconds. How much current do you think it is drawing for those few seconds?
 
For JimDawson, I didn't think there would be that much load on the start capacitor as it was only going to be energized for a few seconds. How much current do you think it is drawing for those few seconds?

A lot :) But I can't really give you a number. Best guess might be at least double the motor nameplate amps.
 
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