AC Motor Speed Controller

AC Motor Speed Controller

Designed to control AC motors with carbon brushes (drilling machine, vacuum cleaner, saw, Â…). High torque, even at low r.p.m. May also be used for low voltage loads (24V). Supply and load circuit electrically isolated from one another.


  • L: 5" W: 3" H: 2"
  • Controls speed from about 5% to 95%
  • Board Requires 120VAC or 220VAC (Line cord not included)
  • Load Supply can be from 24VAC to 220VAC @ 5.5Amps Max
  • Main and Load Power Supply are Galvanically Seperated
  • Includes Anti RF Interference Circuit

AC Motor Speed Controller Reviews:

  • --> AC Motor Speed Controller Kit

    I just assembled and tested your AC motor speed controller and I have to say I am 100% satisfied with the outcome. This was the first electronic kit I’ve ever assembled and it went together with few problems.

    I bought it to slow down the speed of a portable table saw to quiet it down. 3 horse power and 5000 Rpm was a little excessive for the ¼ inch poplar and ½ inch particle board I use four building musical instrument cases in the middle of the night.

    I am a 37 year old aircraft mechanic with very little experience with soldering and electronics; I did have every tool I needed to assemble the kit because of all the tinkering I've done over the years.

    Everything on the board was easily accessible for assembly however these are the problems I had in putting it together. I’m sure anyone with more experience than I with electronics wouldn’t have any of these problems. This is for the person who has as much or less experience with electronics than me.

    1. The instructions were translated to English from another language. Don’t let this scare you.

    2. The instructions tell you to choose between 2 resistors for American and European AC frequencies but it only gives you the one for the European frequency. It works just fine with the resistor they give you.

    3. Pay attention to the fuses they are the same size but have different ratings.

    4. Pay attention to the schematic in regards to connecting the power to the controller.

    I connected a medium duty power tool replacement cord to the input of the board and a female AC outlet to the outlet so I can plug in the tool I need to slow down.

    There are two “knobs” on the controller, one internal and one external. You can turn the external one with your fingers but you need a small screwdriver to control the internal one. Between the two you can control the speed of the motor throughout most of its range.

    I hope this helps and good kiting.