# Wiring question...



## Vintagercr (Oct 1, 2012)

Getting ready to pull wire for my new WEG VFD to run my  3 phase 2hp Bridgeport motor...  Question, should I pull 3 wire or 4 wire 220V??

Thans in advance for you help.

Dino


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## Rbeckett (Oct 1, 2012)

Depends on the code for your area.  If there is no code requirement I would just pull 3 to save a little on the wire.  Just my .02, hope it makes sense.
Bob


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## Vintagercr (Oct 1, 2012)

Hi Bob,

Thanks for the prompt reply.  I actually have enough #6 to do the 4 wire just wasn't sure what that would get me or if the inputs of the VFD can accommodate it.... (Waiting on the delivery of the VFD).

More thoughts welcome.

Dino


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## arvidj (Oct 1, 2012)

Vintagercr said:


> Getting ready to pull wire for my new WEG VFD to run my  3 phase 2hp Bridgeport motor...  Question, should I pull 3 wire or 4 wire 220V??
> 
> Thans in advance for you help.
> 
> Dino



I would run the 4 wires. If you only run three you will have the two hots and the ground and then "only" have 220 at the machine at the end. If you run four you will have the two hots, the neutral and the ground which means you will have two 110's plus the 220 at the end.

The VFD is only going to need to 220 but if you ever decide you want to put a 110 device on the circuit ... like maybe a light or a tachometer circuit or ... and it uses 110 it is easy to put a 110 outlet next to the VFD and wire it up.

That is how I set up the VFD on my mill and drill press. There is a junction box next to the VFD that has a DPDT switch on it that switches the 220 to everything down stream ... i.e. the VFD and the following items.

(a) a switched 110 volt outlet and 
(b) an always on 110 outlet.

Assuming the 220 is on the switched 110 outlet turned out to be nice for the lights that I have added to both machines and the always on turned out to be convenient for the Tachulator wall wart that is on the drill press.

Arvid


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## Vintagercr (Oct 1, 2012)

Hi Arvid,

Sounds like a reasonable idea.  Thanks for the input!

Dino


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## Vintagercr (Oct 3, 2012)

Got my WEG VFD delivered... Very nice unit.  Very easy to install and easy to use. 
Thanks again for the wirng feedback!

Dino


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## Rbeckett (Oct 3, 2012)

Arvid is right.  I didn't consider the 110 option and if you have the wire why not?  That way you can have 110 and 220 readilly available for various things like lights and axis drives.  I retract my original thought and believe Arvid is on the right path for sure.
Bob


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## Kennyd (Oct 3, 2012)

I am pretty sure my Teco VFD would not take #6 wire.  I just cant see using #6 when #12 or even #14 would due perfectly well.


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## Vintagercr (Oct 4, 2012)

Ok... Thanks again for all that responded.  Now that I have it all hooked up and working as advertised my next question is.... Why would I use the VFD to control the speed vs. the speed wheel on the mill itself?

Dino


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## Tony Wells (Oct 4, 2012)

Dino, it's easier, for one thing. More accurate for another. And probably quicker to change. You gain range if you use a combination of the two also.

Plus it will save wear and tear on the Reeves drive. I've never been fond of them. I'd take a VFD over one any day.


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## JLeather (Oct 4, 2012)

I assume from your question that you've got a vari-speed BP head.  On my J-head with step pulleys it's no contest to using the VFD instead of the belts, unless I need to really speed up or slow down.


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## Vintagercr (Oct 5, 2012)

Yup, I do have the 2hp variable speed head.  It's just as easy and quick to turn the dial as it it the potentiometer.  But I do like the fine tuning capability with usng both.. But then again not sure I need to be that precise with a garage tool.

Thanks again,
Dino


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## Tony Wells (Oct 5, 2012)

Very likely true. Not many "need" the speed control of the VFD. The primary reason I believe most hobbyists use them is to deal with the single phase vs three phase problem. The variable is merely a bonus. I've thought about one for my bp clone, it's a step pulley, but as long as I've used it like it is, I wouldn't know how to act with a VFD. Plus I have three phase in the shop. Maybe someday I'll find a machine where I'll see enough advantage to get one. 

People building CNC mills who intend to use a rigid tapping cycle would need one if their control didn't include a spindle encoder and accurate speed control. I've seen it done with the Reeves type drive, and it's a little iffy dialing in the speed. And you will break a few taps if you don't have the speed close. Even with an accurate VFD, without an encoder, you're limited to one shot tapping.


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## Vintagercr (Oct 11, 2012)

Well, now that I've been playing a bit more with the unit I must admit, I find myself using the speed control on the VFD much more than the wheel on the unit BP.  I basically set the mill speed to about 2400 rpm and then adjust the VFD.

lovin' my WEG!

Thanks again,
Dino


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