Help wiring switch to vfd.

woodtickgreg

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Well I am finally working on getting the south bend wired up. I got a new fully enclosed vfd, teco fm50-101. I understand how to wire the 110v input and the 220 3 phase output to the motor. The part that I dond understand and that the manual is not clear on at all is how to wire the stock cuttler hammer switch up. The manual says to use a 2 conductor shielded wire, I purchased that. I see on the vfd where the switch is supposed to be connected, it has fwd, rev, and I don't know if you are supposed to use 12v power or not? I really do not understand how this switch is supposed to be wired. I took some pics of the vfd and the switch in hopes that maybe some one here smarter than me can help me with this.
vfd,-electrical-001.jpgvfd,-electrical-002.jpg

vfd,-electrical-001.jpg vfd,-electrical-002.jpg
 
I found the manual (they make it kind of tricky.. not sure why).

http://www.tecowestinghouse.com/products/Drives/fm50.html

It's the lowest link in the right hand panel. Check out page 17 of the manual. Looks like the 12V is for digital (switch) control power, and the 10v is analog for the speed control (10k ohm potentiometer).
 
I found the manual (they make it kind of tricky.. not sure why).

http://www.tecowestinghouse.com/products/Drives/fm50.html

It's the lowest link in the right hand panel. Check out page 17 of the manual. Looks like the 12V is for digital (switch) control power, and the 10v is analog for the speed control (10k ohm potentiometer).

Yes I have that, but I still don't understand wher the 2 wires are supposed to connect to? I'm assuming one to fwd and one to rev, but how and where to connect on the switch. I'm guessing the top 2 terminals of the switch would be used?
 
DMS is correct. You should connect the 12v to FWD or REV to make the VFD run that direction.

You simply need to find two sets of terminals on the stock switch, one that makes contact with the arm in the Forward position, and one in the Reverse position. Just use a multimeter to check for continuity as you switch the handle. Just be sure to use terminals that are not active at the same time!

I have attached a drawing of a typical drum switch, and if yours is similar, you would wire it as follows. (It looks to me like your switch is upside down, compared to the drawing.)


12v to terminal 3
Fwd to terminal 4
Rev to terminal 1

Connect the Shields of both cables to the ground at the VFD ONLY!! Do not connect the shield at the switch. This would create a ground loop, and could damage the drive. Same goes for the motor, when you wire it. (And shielded cable is not REALLY necessary if you do not have electronics nearby, eg a computer)

Also, ignore the third vertical set of terminals, the set without screws. This set should not get wires, as the are only there for ease of construction.

-Cody

image.jpg
 
Ok so your saying that the 12v is used to send a signal to the switch and back. That would mean I need a 3 conductor wire that is shielded, the o.m. called for a 2 conductor, all very confusing. To find which terminals on the switch are used I would touch #3 with the meter and move switch to forward and see which terminal has continuity? And same for reverse I assume.
 
Ok so your saying that the 12v is used to send a signal to the switch and back. That would mean I need a 3 conductor wire that is shielded, the o.m. called for a 2 conductor, all very confusing. To find which terminals on the switch are used I would touch #3 with the meter and move switch to forward and see which terminal has continuity? And same for reverse I assume.

vfd,-electrical-002.jpg

This should be what you find with your multimeter.

Flip the switch into forward, and measure between the center terminal, and the one to the left, as shown in the photo. This SHOULD show continuity. Measuring between center and down left, there should NOT be continuity, with the switch in forward.

Flip the switch to reverse, and the readings should follow. Center to left should NOT connect, and center to down left SHOULD connect.

You don't really need to get 3 core wire, unless you really want to. There should be no issue making two cable runs, and just leaving one conductor unused. Just make sure to ground both shields to the drive.

-Cody

vfd,-electrical-002.jpg
 
Codered741, you da man! That is exactly what I was needing, this helps a great deal. THANK YOU! I found the wire for the switch, now just have to find 14/4 awg shielded for the motor, I only need about 10' of it, having a hard time finding it.
Since I have your attention........what do you think about a twist lock plug in the output 3 phase wire? Would that kill the shielding?
 
Hi Greg,
shielding is an outer wrap of material around wiring that keeps stray electromagnetic signals from interfering with a circuits purpose.
as Cody said earlier, unless you have some serious interference from other electronic devices, shielding out your 3 phase is not necessary, and will be quite expensive to find sufficient cable that is shielded.
i would more worry about the input side for shielding, your 3 phase motor will not care about shielding.
the freq controller won't care either about the output.
I use twist locks on shielded equipment all the time, no danger there!!!
mike:))
 
Since I have your attention........what do you think about a twist lock plug in the output 3 phase wire? Would that kill the shielding?

I'm assuming the receptacle is going to be in the VFD enclosure (or real close). If so, you should be ok, just make sure to connect the shield to the ground in that cabinet. Do not connect the shield at the other end. The cabinet should have a good protective earth, nicely terminated.
 
Greg,

Glad I could help!

As I said earlier, shielding is really NOT necessary for your cable, input or output, unless you are running other sensitive electronics nearby.

That being said, if you wanted a plug between the output of the VFD and the motor, just get a connector with an extra pole, and connect the shield through that. Yea there will be a little EMI leakage at the plug, but your drive won't put out enough to affect anything. (Unless your computer is sitting on the VFD, in which case you need a better place for the computer).

McMaster-Carr has 14/4 shielded cable that would work, but it is not cheap. #9936K75.

I personally run all of my machine VFD's with unshielded cable, and have never had a problem. With CNC machines this becomes an issue, because electronics are necessarily close to the machine, and often the cables need to be bundled together.

And make sure that the VFD is OFF, BEFORE you unplug the motor. Failure to do so can damage your drive.

-Cody
 
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