I have a single phase motor with five outgoing wires: white, brown, red, blue and black.

  • white - has no resistance with any of the others.
  • brown-blue = 136Ω
  • brown-black = 366Ω
  • brown-red = 108Ω
  • red-blue = 25Ω
  • red-black = 260Ω
  • blue-black = 236Ω

here is my motor: 2 1


closed as off-topic by Voltage Spike, DerStrom8, Dave Tweed Jan 10 '18 at 20:19

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  • 1
    \$\begingroup\$ Your description is confusing and the motor is complicated. There is no standard for color coding motor wires. The motor may be defective. There is little chance of figuring out the correct connections based on resistance readings. Someone with a lot of experience and more test equipment might be able to figure it out, but it is probably a waste of time to attempt to figure it out using an internet forum like this. \$\endgroup\$ – Charles Cowie Feb 15 '17 at 15:07
  • \$\begingroup\$ Stainless answer is very correct. There is no assumptions as the details are technically and theoretically correct. With the second upload of drawing with the starting and main winding, the details are very correct and there is nothing that will prevent the motor from running. The rest job is for OSM to wire correctly \$\endgroup\$ – Kamah Dec 27 '17 at 7:30
  • \$\begingroup\$ If you do not know which wires are connected to the start capacitor, you are lost unless the MFG has a diagram for you. \$\endgroup\$ – Sparky256 Dec 29 '17 at 5:53
  • \$\begingroup\$ If you know where the motor came from there may be a chance to find how it is intended to be used. Tracing existing wiring or circuitry would be a great help. \$\endgroup\$ – KalleMP Dec 30 '17 at 12:36

If you have a single-phase three speed split capacitor motor, the following will explain your readings:


simulate this circuit – Schematic created using CircuitLab

Numbers in Green are calculations, which correspond to your measurements.


I believe that @StainlessSteelRat has presented a pretty likely configuration for the "Run" coil and the speed selections. I suspect that the white wire is connected to an internal capacitor that is connected in series with the "Auxiliary" coil. That would be one explanation for infinite resistance between the white wire and the other wires.

If all that is correct, the diagram below would be the complete connection diagram.

enter image description here

One more thing to keep in mind is that the actual operating speed for a motor like this is determined by the load. With the motor disconnected from the load the speed will be close to 1500 RPM regardless of the connection. The load will slow the motor down. The medium and low connections make the motor weaker so it slows down more.

  • 1
    \$\begingroup\$ You appear to have a certain technical clairvoyance. I would support your assesment enough to test the setup. A high wattage mains rated incandecent lamp in series wwith the first test will limit fault currents. If the motor tries to spin and the lamp glows then there is hope and removing the lamp could be tried briefly. Try the slow an fast speeds with the lamp, one may run while the other does not manage. \$\endgroup\$ – KalleMP Feb 16 '17 at 20:36

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