Reverse polarity relays

Thread Starter


Joined Oct 5, 2011

I'm working on a fun fair ride (kind of like a pirate ship). For this, I have to be able to switch 12V motors on/off and let them spin left/right. I know I will need 2 relays for this, but I have no idea how to hook these up. If someone can help me out with a schematic drawing I would be very thankful.

Thanks in advance.



Joined Oct 15, 2009
Specs/part numbers of said motors?
Do you just want a toggle switch for on/off and a toggle for left/right?
Do carnivals not require proper engineering/licensing for ride designers for liability purposes? No offense but these are the type of posts that scare me and will guarantee my kids never go to carnivals.

Here is something to get you started learning..


Joined Jul 17, 2007
This is one way to do it:

Pressing S1 will cause the motor in one direction; pressing S2 runs the motor in the opposite direction. If no buttons or both buttons are pressed, the motor terminals are shorted together; nothing bad will happen.

However, if you have the motor running in one direction and try to reverse its' direction suddenly, that will put a very high load on the entire circuit.

You may be able to use automotive SPDT relays if the current rating is suitable for the motors.

If the relay coils have a resistance greater than 120 Ohms or a rated current less than 100mA, you should use 1N914 or 1N4148 diodes instead of the 1N4004's.