How to Connect a Speed Potentiometer to a VFD (Video)

By Tyler Simmons on 20th Mar 2014

Video Transcript

I’ve got an F700 Mitsubishi here and I am going to show you how to hook up the speed potentiometer – or the speed pot. The camera here is going to show you the two screws on most of the small sizes of drives. This is what we have here, just a small horsepower in our demo unit. I am going to go ahead and remove the keypad, these two screws are already loosened. We are going to go ahead and open the cover, going to the left, and then I am going to lift the flap. Hopefully we have a good shot of the markings. These markings on the flap correspond to the terminal block on the control side of this inverter drive, and the ones we are going to be focused with right now are terminal 10, terminal 2 and terminal 5.

These three terminals correspond to the speed pot. The terminal 2 is the wiper, or the center wire, on the speed potentiometer. Terminals 10 and 5 are the outer two wires and typically, once you land those, the speed pot turns in a clockwise fashion and should be increasing in speed. If it is not (increasing in speed), just simply remove the wires that go to terminal 10 and terminal 5. You can see the colors we have here, marked on our drive. We have a black, white, and a red shielded cable. I am going to shut that, and here is our speed pot on the unit itself. One thing to keep in mind is with this setup, you will need to add a jumper or a switch to start/stop the drive using terminals STF and SD.

As you can see, we went ahead and put the cover back on , and we plugged in the parameter unit. Of course, I have the power on it this time and I am going to go ahead and reiterate what I talked about. We have a little toggle switch, this one in this particular case, is going to STF and SD. That will give the start command, I will apply it now, and our motor is starting to run. You can see that our speed pot, as I turn up the wheel, is increasing in fashion and starting to speed up. As I take the speed pot back down, in the counter clockwise direction, you will notice the motor comes back and begins to slow. Again, the start command STF to SD, if I go ahead and apply that it takes away the total start command.