I know this has come up many times but I've yet to hear a good way to deal with the vfd issue. Here's where I am. I have a very old Haas milling machine that I completely rewired. Machine has run fine for years until I moved my shop. This shop has high leg 3 phase 240. L1 and L3 are 120 to ground/neutral and L2 is about 210 to ground. Phase to phase is fine.
But, as covered many times on the net, the issue lies in that high leg when connecting to a vfd. First issue, I get a overvoltage fault because of that high leg charging up the capacitor way too high. Currently this has a AD G3 7.5 hp low voltage drive.
I purchased a rotary phase converter that was supposed to be really really smart and be great for vfd. Totally false as it generated 3rd leg was at 274 volts. Even worse so this was a waste of time.
So I now have this silly idea of using a 20 hp AB powerflex 755 that I have laying around. This is a 480 drive so my thinking is that the overcharging part will be fine. The unbalanced currents should work because I have 27 amp drive.
I'm pretty sure I can disable the undervoltage fault that certainly will occur. I can also program the name plate data for low voltage. This drive does allow for the removal of the ground screws so it will better tolerate the open delta 3 phase. On that note, I could add a 1:1 delta wye transformer as well.
Any thoughts on what I might be completely not understanding.
But, as covered many times on the net, the issue lies in that high leg when connecting to a vfd. First issue, I get a overvoltage fault because of that high leg charging up the capacitor way too high. Currently this has a AD G3 7.5 hp low voltage drive.
I purchased a rotary phase converter that was supposed to be really really smart and be great for vfd. Totally false as it generated 3rd leg was at 274 volts. Even worse so this was a waste of time.
So I now have this silly idea of using a 20 hp AB powerflex 755 that I have laying around. This is a 480 drive so my thinking is that the overcharging part will be fine. The unbalanced currents should work because I have 27 amp drive.
I'm pretty sure I can disable the undervoltage fault that certainly will occur. I can also program the name plate data for low voltage. This drive does allow for the removal of the ground screws so it will better tolerate the open delta 3 phase. On that note, I could add a 1:1 delta wye transformer as well.
Any thoughts on what I might be completely not understanding.