How to wire 480v 3 phase HVAC - Gb Electrical 100 Amp GE Load Center

SOURCE: I need to wire up a baldor 3 phase motor 208-230/480 15hp and dont have the wiring diagram to know what wire is what or where to hook it to?

Hi Casey, I'm an electrician and can help you with this problem.

First, a disclaimer. Without the catalog number of the motor you have, or a wiring diagram for it, no one can tell you how to wire this motor with any certainty. With that said...

Nearly all single speed 3 phase motors have 9 leads (numbered 1 thru 9) and can be wired for either "high" or "low" voltage. Most of the time, high is 480 volts and low is 208/240 volts. Given that you posted the amperage as "41-38 / 19", I am 99% confident that 41 amps is at 208 volts, 38 amps is at 240 volts and 19 amps is 480 volts. Further below is the way to wire unless the motor manufacturer or name plate indicates differently. You will need to determine the voltage of the appliance this is going to be installed into. You should be able to find this on a name plate of the appliance - but it may provide a dual voltage spec here, too. If this is the case, you will need to *carefully* measure the voltage with a meter, or find out the voltage of the electric panel that feeds the appliance.

Once you have learned the incoming voltage, you will connect the motor as such when L1, L2 and L3 are the line voltage supply wires and wires 1 thru 9 match the numbers on the nine wires from the motor.

208/240 or "Low" volts:
Motor leads 4, 5 & 6 connected together and wirenut.
Motor leads 1 & 7 to L1 and wirenut.;
Motor leads 2 & 8 to L2 and and wirenut and lastly,
Motor leads 3 & 9 to L3 and wirenut.

480 or "High" volts:
Motor lead 1 to L1 and wirenut,
Motor lead 2 to L2 and wirenut,
Motor lead 3 to L3 and wirenut,
Motor leads 4 to 7 and wirenut,
Motor leads 5 to 8 and wirenut and lastly,
Motor leads 6 to 9 and wirenut.

The motor should be operated briefly or "jogged" to determine the direction the motor turns. If the motor rotation needs to be changed, simply swap any two "L" wires (swap L1 and L2, or L1 and L3, or L2 and L3). Test once more to verify rotation and when correct close the wiring compartment and complete the installation. Swapping the L wires will likely be much quicker and easier to do at the magnetic contactor instead of the the motor's wiring compartment. Either location is acceptable.

You should try to obtain the name plate data for this motor - if at all possible to to make sure of the voltage and wiring method. I hope this helps & good luck!