hey everyone new to forum i have a project Im working on and need a little help with wiring a 12vdc motor. problem is i want variable speed in one direction only .components being used are 30 amp pwm with 4 connections 2 for power & 2 for motor . for reversing the motor i was thinking of using a drum switch. I want the motor to be variable speed in the forward direction. thank you all in advance for any info or suggestions

 

you can reverse polarity using dpdt switch or relay (must be rated for current you will use).

then get something like kitsrus kit 67:
http://www.paia.com/KRUKits/K67/K67v3.pdf

and if you want speed control only in one direction and the reverse in full speed thensomething like this should do;