1981 Supermax YC-1 1/2VA mill (BP clone)

Finally got the rest of the top end done. Now just waiting on the motor shop. They don't seem to be in any hurry either. :mad: Guess I'll wire what I can while I wait.
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Well damn. I was reading up on the vfd to plan out all the wiring and realized it doesn't have multiple motor parameter capability even though I could have sworn it did. So now I'm trying to decide whether or not to get another vfd and just have dedicated units for each machine or stick with the original plan to run both off of one vfd. I'd have to return the one I've got and try to find one capable of multi parameter. I've got money in the enclosure and switching too. Although, I still may be able to use those. Hmmm...
 
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I would say it does not pay to try to use multiple motor settings in a VFD for two separate machines. It becomes a bit complicated and messy. I have done it on the same motor for different pole settings, and even there I ended up just replacing the motor at the end. At the cost of VFD's, you are better off buying a separate VFD for each machine and the related switch gear. It is not only a function of the separate motor parameters, but often the program parameters/inputs, etc. are different. Unless both machines are the same, I do not recommend it. Many people use something like the Teco L510 for the mills, but I often do not recommend them for lathes because they lack the ability to use an external braking resistor.
 
Thanks for the input. That confirms what I've been reading so I'll probably get another VFD. I don't know if I need a braking resistor with my Pratt & Whitney being an engine lathe since you're not starting and stopping the motor all the time and the motor isn't stopping the mass of the drivetrain and work. I guess maybe when you shut off the motor when you're done the spool down could generate power but the VFD controls the spool down speed of the motor.
 
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So, just got done talking to my resident VFD expert (my brother) who schooled me on VFD braking. He works at a power plant and tweaks on VFD's everyday. I gave him all the info and he said I shouldn't need the braking resistor. But, I'm still going to get one that has the option for posterity. He also recommended getting one rated a half HP higher than what I need so, armed with that info I'll use the 3hp non-brake resistor capable one I already have for the 2hp mill motor and order a 3.5hp brake resistor capable unit for the lathe, reconfigure the enclosure for 2 VFD's and add a cooling fan and vents.
 
Decided to go with a Hitachi WJ200-022SF. Based on reviews and specs it should be good.
 
There are no 3.5Hp VFDs, typical sizes would be 1, 2, 3, 5, 7.5, 10, 15 and 20Hp in the range that most people use them. Typically those up to and including 3 Hp are available in single phase models, very few are single phase input in the 5-10Hp range (up to 5 Hp Yaskawa and up to 10 Hp Invertek). Most 3 phase VFD's can be run on single phase but need to be derated on their output current rating, these days the usual factor is to divide the output current by 2, but it varies by VFD model so you always need to refer back to the manufactures derating. There are some cases where you might want to oversize a VFD, but in general as long as the VFD's rated output current is higher than the motor full load amperage and factoring in any derating and the type of load (ND, HD) you do not need to oversize it. If you have a 3 Hp motor on the P&W lathe then I would recommend one of the following VFD's:

Hitachi WJ200-022SF rated output in HD mode is 11A
Teco E510-203-H-U rated output in HD mode is 10.5A
Invertek ODE-3-220105-1F42 rated output in HD mode is 10.5A
Yaskawa GA50UB012ABA rated output in HD mode is 11A

Wolf Automation often recommends Fuji Drives, I have not used them but find they are a bit quirky on some of their programming functions. They are reasonably priced and a good option for larger or difficult loads where one needs to oversize the VFD. Many people use the Hitachi drives, they are robust and reliable. The biggest single phase rated model is the WJ200-022SF, if you wanted to run say a difficult start 3 Hp load motor then one would use the the wj200-055LF which is a 7.5 Hp 3 phase input VFD so in single phase input derated mode would equate to ~3.5 Hp. Also if you look at the output amps/duty

As far as electronic braking, it depends on how the lathe is used and whether you are using the clutch/and or electro-mechanical braking system. The other thing to think about is if the machine is running and you press the E-Stop how fast will the lathe stop. SInce a braking resistor only costs around $60, I would install one as an added safety feature.
 
A quick update on this mill project, got the vfd and the remote switches wired and after some troubleshooting and a call to my brother, I finally got the settings right and she's under power! Unfortunately I've been too busy to make any chips with it yet. At some point after my lathe resto is done I'll put some time into cleaning it up but for now The next item on the list is pulling the table and checking the bottom end. I think one or more of the way oil passages are clogged and feel like the knee is a little too hard to crank. It might be a while but I'll update when I get back to it.
 
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