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Drum Switch Wiring

A Richardson

Plastic
Joined
Feb 3, 2007
Location
Oklahoma
I am trying to connect my ACTech VFD to my BPT and I have a question. When I pulled the cover off of my drum switch I found 6 wires coming out of my motor and they were all connected to the reverse side of the drum switch. There were jumpers running to the forward side of the switch.

Did one of the previous owners do this? why?

Can I just move these wires to the same terminals as my power wire coming into the box, i.e. the center position? Do I move all 6?

What is the order of legs? Is it 123 left to right?

Okay that was more than one question, any help is greatly appreciated.
 

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Well, I'm guessing the jumpers are to supply power to the other contacts..

Usually a drum switch is setup with the power input wires connected to both sides of the drum switch. The jumpers are switched around to setup the other side for reverse. The other way to do it is to connect the motor to both sides (which would explain why there's 6 wires) and switch a pair of wires. The jumpers only supply power from one set of contacts to the other. Don't confuse the physical location of the terminals with the internal configuration of the switch. Just because the terminals are physically on the reverse side of the switch doesn't mean they're all for reverse. I had to take my drum switch apart to figure it out. The terminals aren't layed out the way you'd expect in relation of the internal contacts. As for the order of the wires, it really doesn't matter. If you get it wrong, it will just spin in reverse. Then you simply pull 2 adjascent wires off, and switch them around and it will spin forward. :cheers:
 
I have a sm230s AC Tech VFD. My drum switch was used to connect terminals 1 and 11 for forward and 11 and 13A (which was programmed) to be reversed. I had to cut one leg (the copper connector) of the drum swith off to accomlish this task. I hope that makes sense.

neilca
 
You will need to do the following:

First, you need to look at the motor nameplate and determine how to connect the motor leads for the voltage you are using (I assume it will be 230 volts).

Second, connect the motor leads properly then wire DIRECTLY from the VFD output terminals to the motor, 3 wires.

Third, you need to follow Neilca's instructions on how to connect the drum switch to the control terminal strip in the VFD

Fourth, you need to program the VFD to accept the external Start, Stop and Reverse. Neilca should be able to help you with this.

I have done this using Hitachi VFDs but not AC Tech so I do not know the programming steps. I do have the orginal Bridgeport drum switch wiring but that is of no help for what you are doing. Just follow what Neilca has already told and you can wire up the drum switch for controlling the VFD. It is easy to do and the mill controls will work as original.
 
Thanks for all of the responses. You have explained a lot.
Neilca, I had planned on initially using the drum switch as on/off/direction but I have decided on mounting a seperate panel on the front of the machine with seperate switches for each and a pot for speed control (an idea gathered from this forum). There is an EE at our plant that can decipher the instructions.
 








 
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