I purchased a Marathon 110/220 3/4hp electric motor to be used for a 24" flat drum sander. To wire the motor for low volt use the wiring diagram shows the black, white and yellow wire tied together going to houshold current. The diagram does show it, I assume this connects to the ground (white) wire to houshold current. On the diagram, the purple wire is connected to household current. I'm assuming this is connected to the black wire (110v). The other 3 wires at the motor, brown, white and red are tied together, they are not connected to the household wiring. When I wired in a two terninal on/off switch, when the switch is off, the motor goes on, when the switch is off the motor is on. At the switch I have the black 110v wire from household current hooked to one terminal. The other terminal at the switch is connected to the black wire going to the motor, which is the purple motor wire. I switched the black wires at the switch and it makes no difference. What's wrong?
Sounds like a bad switch. I have had new switches from the factory shorted internaly.
If you have an ohm meter you can verify this.
23 yrs as an electrician, self employed contractor, municipal inspector
So the motor and switch are wired correctly?
If the motor runs with the switch off, there is something wrong with the switch.
But in looking over your original question, you mention the same color wire twice in two different connections..
If this is a six wire motor usually you will have Y, BLK ,W in one group and O, R, Blu in the second. Is this what you have?