Reverse Polarity Switch

[waco kid]

I'm installing a reverse polarity switch in my 4 speed ceiling vent fan. Can anyone tell me the best place to put the switch, at the feed, before the speed control, or after the speed control, between it and the motor? Thanks, Bruce

[Mudsock]

It won’t make any difference. A DPDT switch swapping the positive and negative wires in either location will have the same result.

[Cypressloser]

It shouldn't make any difference, however I would install the switch before the speed control to always have full 12 Volt power on it as the switch can be the weakest part. Be aware that it is hard on the fan motor to switch polarity under full load and can possibly blow the fuse, you may want to let the fan spin down for a few seconds before you switch.

[spyderRV]

Originally Posted by waco kid

I'm installing a reverse polarity switch in my 4 speed ceiling vent fan.

I did this mod. However, it doesn't move much air in reverse. I suspect it is the blades are curved the wrong way in reverse.

[waco kid]

Update, I tried putting the reverse polarity switch before the speed control switch, and it did not work, I then tried it between the speed control and the motor and it worked fine. The fan I did this modification on is a maxxair.....Bruce

[Cypressloser]

You're right, I've given you bad advice. The switch would reverse the polarity on the the speed controller. I should have known because a few years ago I wired a set of 12 Volt linear actuators on a speed control knob used as clamps and knew to avoid this trap.
Please accept my apologies.

[Mudsock]

I assumed that the speed controller was a rheostat that simply dropped voltage. Apparently it is an active device.