Wiring a single phase motor to drum switch
My question isn't about phase conversions but i figured this board had the most knowledgable electricians. I converted my Rockwell mill to a single phase motor years ago. I have been running it with the original drum switch turning in one direction (CCW). I would like to wire it to reverse also. According to the instructions on the motor, a GE 3/4 hp capacitor start/capacitor run, two wires have to be switched in order to reverse rotation. These wires are not the power wires but wires attached to the motor. How can I do this with the drum switch?
Do you have a diagram of the drum switch showing the contact setup ? Most single phase motors can be reversed by interchanging #5 lead with #8 lead of the motor
Basically you will need a drum switch with enough contacts to do the job. For single phase you will need a 4 pole drum switch to be able to break both hots and to switch the leads 5 and 8 (which you will need to bring from the motor to the drum switch).
You will need to post a diagram of your drum switch for anyone to be able to tell you how to wire it as there are more than one type.
I have a three pole drum switch. No wonder I couldn't figure this out. I think I will leave it a one way until I have to change.
Only three poles are required to perform both the motor controller and disconnect functions.
First, you have to decide whether you are going to reverse the run winding or reverse the start winding.
Usually, it is best to reverse the start winding, as this makes conversion from 120 to 240, or from 240 to 120 a little easier.
Let's say your drum switch (Furnas, for example) passes through the L1 and L2 on the outer two poles, and the reversing is done on the inner pole.
Connect T1 to the drum switch terminal which corresponds to L1 and T4 to the drum switch terminal which corresponds to L2.
If the desired voltage is 240, then connect T3 to T2.
If the desired voltage is 120, then connect T3 to T1 and connect T2 to T4.
That connects the run winding, which is not reversed.
Now, for the start winding, assume the wires are labeled T5 and T8 (this varies quite a bit).
For 240 volts, connect one start winding wire to the junction of T3 and T2 (the start winding is always operated on 120 volts, even if the motor is 120/240 volts), and the other wire to a remaining drum switch terminal.
For 120 volts, connect the start winding wires to the remaining drum switch terminals.
An example of this setup for 240 volt power shown here:
There are at least two different types of 3 pole (6 wire) drum switch connections.
One looks like this:
and some look like this:
Can you either post a picture of the internals of the switch, or tell which type you have. If we know the switch type, and the numbers on the wires in your motor, we can tell you exactly what wires to connect to what terminals.
My switch is the first kind you listed. Does the above wiring diagram apply?
The wring diagram I put up there uses the most general kind of drum switch, a
three pole, double throw, center off type. All of the contacts really have to be
individually available for that to work.
The short answer, without seeing your swich, is probably not.
Now that we know what type of switch you have, we need to know more about your motor. Does it have 4 wires comming out and 2 need to be swapped to reverse? Look at the diagrams below and see if any of them fit your application.
This is what I know about the motor...
It is a GE KCR49WN6078 catalog number C1412. Single phase capacitor start/capacitor run. 3/4 horse.
I have wired it with two 110V legs going to the terminal blocks and a ground. The instructions on the motor say to swap the black and red wires to reverse rotation. These two wires are not connected to the terminal blocks where the power wires attach.
Hope that helps,
In order to tell you how to coneect the motor to the drum switch, I need to know about the motor and the drum switch. We have completely defined the switch, but not the motor.
How many wires come out of the motor?
How are the wires labeled? (numbers and colors)
Can you post a pic of the motor plate that says how to reverse?
Is the motor dual voltage and if so what voltage are you running?
Can you tell us what wires are connected to what currently? (pics help a lot)
For reference, some standrad drum switch wiring diagrams are shown below, you would need to use the ones in Figure 2 because that is the type of switch you have:
This image shows some connections for a GE KC motor.
I am wanting to change my 110 over to 220. It is Sheldon lathe and has been working fine with 110 but I need to improve the shop so I had 220 installed.
Originally Posted by 2Slow
He was unable to make the drum switch work so I had him stopped because I remembered reading this post some time ago.
My Motor has 6 wires coming from it
It worked like it should hooked up as listed using 110.
drum 1 to t-8 red
drum 2 to t-2 white, t-4 yellow, and white from power source
drum 3 and drum 5 to t-1 blue and T-3 orange
drum 4 to t-5 black
drum 6 to power black
Motor plate says to reverse direction change red t-8 with black t-5
The motor says for high voltage (220)
Line 1 to t-1 and t-8
line 2 to t-2, t-3, t-5
line 3? (I have only 2 lines plus ground) to t-4
Any help would sure be appreciated.
Hey Adrian, just wondered if you managed to find the right way to do it?? I was looking at this thread a little while ago and i've been trying to make sense of what you were doing and how you were doing it.
Originally Posted by Adrianwe
I hope that its all sorted now!!