I am trying to wire a new motor to a variable frequency drive (VFD) and having some trouble figuring out how to wire the motor to the VFD. The motor is a 1 HP, 3-phase, 208-230/460 volts, and I'm wiring a 120 VAC supply voltage into the VFD, which steps that up to 3-phase 230 V. I have included a picture of the wiring diagram attached to the motor below.
Based on that diagram and the fact that the motor will be operated at 230 V, I gather that wires 9 and 3, 8 and 2, 7 and 1, and 4 and 5 and 6 all need to be wired together - giving me 4 separate wire bundles. The VFD has wire terminals for U, V, and W, so it looks like I have 3 terminals and 4 wires, so I'm not sure which wires go to the U, V, and W terminals on the VFD or what to do with the extra wire bundle. I have included an image of the motor wiring diagram from the VFD manual below.
I was thinking that the extra wire bundle would be a ground, but there is also a green screw inside the wiring box on the motor that I'm thinking is where I connect the ground wire (and connect the other end to the protective earth PE terminal on the VFD), but please correct me if I'm wrong. With the extra wire, I'm also left wondering how to differentiate between U, V, W and whatever the 4th wire is. In the VFD motor wiring diagram, I also can't figure out what the Physical Earth Shielding (PES) is - is it just saying to use shielded wires and attach the shield to ground? The model numbers for the items are: Baldor CEM3546 Motor, and Lenze SMVector ACtech ESV751N01SXB. So my specific questions are:
- What is the 4th wire?
- Where do I connect the 4th wire?
- To ground the motor, do I attach a wire between the green nut and the PE (protective earth) terminal on the VFD?
- By connecting the ground wire on the incoming 120 V single phase to that same PE terminal, is the motor grounded?
- Is the PES just another way of saying to use shielded wires, with the shielding being attached to ground? Is this really necessary?