I have a 3 speed fan motor salvaged from an old box fan. I want to repurpose it to power a small homemade disk sander. The motor wires had been disconnected from the little rotary switch, and I don't have enough electrical savvy to know how to rewire them to a NEW switch (The old switch is falling apart). The motor wires are white, black, blue, and red. I don't really need any speed except high for the sander, but I'm puzzled about how to achieve the highest possible speed. I connected the neutral ac line to the white motor wire, and the hot ac line to each of the other motor wires in turn, and all 3 seem to produce about the same shaft speeds; around 1140 rpm. If all 3 produce about the same speed, that must mean the fastest speed is achieved by connecting, in the switch, 2 or more of the motor wires together. That sounds good in theory, but I'm reluctant to test it for fear of damaging the motor. Any help greatly appreciated.