Reversing and speed control of Universal AC/DC gearmotors


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I am currently confused on the best means of rotating 2 gearmotors. I have built an astronomical dome and have mounted 2 1/15 hp diagonally opposite each other. Each motor has 4 leads each (2 leads for line/2 leads for connections). The problem is that each set of wires per motor must flip/flop in parallel together in order to achive the correct CW/CCW rotation for both motors. I have tried using a 3pole doublethrow paddle switch 110V,15A but this dosen't seem to work. I was told I'll need to use 2 pushbuttons,1 for forward other for reverse. Also need 4NO/4NC set of contacts plus 1 each 120V coils. This is supposed to do the trick. I am not a control wiring genius so some really good wiring diagrams would be nice. Any help and advice would be greatly appreciated. Thanks David.
David, the four wires going to your universal motor are going to two coils: the stator and the armature. One side of each coil goes to the A.C. line and the remaining two wires are tied together. The two coils are in series across the A.C. line. To reverse the motor swap the connections on either coil. Only reverse one coil. Also, reversing the line connections does not alter direction. You must determine which pair of wires constitute a pair that go to the same coil. The easiest way is on the ohms scale of a multimeter, vom, dmm, etc. With the four wires loose you should get a reading across each pair but not between pairs. If you only read across one coil turn the shaft slightly and try the other pair again. if the gear reduction won't let you turn the shaft, consider the other two wires a pair and don't worry about it.

Now to your problem. To reverse a coil you'll need a DPDT, center off switch. You can get one that is momentary in both directions so that the motor runs in each direction as long as you hold it. The back of the switch will have six contacts. Each row of three is a separate switch. Solder two wires in an 'x' across the outer four contacts. Solder one of the coils' two wires to each of the short crossed wires you've just installed on the back of the switch. Connect one of the middle switch connections to the line. Connect the other middle terminal to one of the other coil's wires. Connect the remaining coil wire to the other side of the A.C. line. Again, make sure the switch has a center off position or the motor will always run. A 'momentary in BOTH directions' means it will only run as long as you hold it. I wasn't sure if you wanted both motors to run together. If so, get a 4PDT switch and wire the next two rows of contacts the same way for the other motor. Otherwise, use one switch per motor. If Radio Shack doesn't stock the switch in the store, mail-order from Mouser electronics. Get a free catalog on-line and order. No minimum and shipping's a few bucks. Good luck.