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Discussion Starter #1
Here's the deal. I have a 220 VAC single phase lathe and just bought a 110 VAC digital readout (DRO). I don't want to run any more power (stupid me didn't run a neutral). I have a transformer out of a 5vdc 5A power supply. The transformer has 4 taps on the primary.
input is 1&4, for 105-125VAC jumper 1-3 and 2-4, for 210-250vac jumper 2-3.

Can I use this similar to a buck-bost transformer and put 220 vac to 1 & 4, jumper 2-3 and then get 110 vac out of 1 and 2-3?? Do I need to run a load on the secondary?? The DRO is 60W

On Topic - the lathe will be used to make suspension parts for the 460 powered cars. May cut a balancer spacer for hte short snout crank.
 

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Electrical

More than likely, that transformer has a selection of input voltages. Jumper it one way, it works with 110. Jumper it another way, it works with 220. You can't wire the 220 portion to 220 and somehow get 110 out of it unless it's a 2:1 transformer intended for that purpose....or you get real lucky. Depending on how the core is wound, you may be able to get 110 out of the primary side when driving the primary with 220. But, this isn't probably what it was designed for, and things like heat might be a problem since you'll be concentrating all the heat/load on one side of the transformer and using in a method not (probably) intended.

Back up one step.

You're running this lathe without a ground? I think it would be worth your while to run one. Reason being is that electrical motors often short hot-to-chassis...and if that happens while you're using the lathe, you run the risk of electrocution on a device that almost certainly has handles you grip and a spinning piece of metal there to hurt you should you get zapped and fling a limb into it. It's not worth it, IMHO. I once got fried using an old metal-body drill on an ungrounded 110VAC outlet...and that was enough for me. I lost muscle control in that hand and couldn't release the drill. It wasn't much fun. If running the wire is that big of a problem is it easier to drive a new ground stake? You really ought to ground that machine.

Back to the question... You can make 110 from 220 with a 2:1 down transformer. They're all over ebay.

http://search.ebay.com/220-110-down-transformer_W0QQfromZR8QQssPageNameZRC0021QQsubmitsearchZSearch

But the right way, and safe way, is to run your neutral/ground.

What do you do for lights and a coolant pump for the lathe? You'll probably need both sooner or later...and they're both typically 110.

Byron
 

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Discussion Starter #3
Lathe has a ground. It doesn't have a neutral. A ground by definition can't carry current (except when it is saving a life)

For light it's right under a 2x8ft lamp. It has no coolant pump, oil squirt can or WD-40 works real good when you need a little help.

Between this info and that on other boards, I'm gonna just buy a travel xformer, slip it in the disconnect box and add a 110 outlet
 

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OK.

If it has a ground, you have neutral (for all practical purposes). But you're right, by "code" you're not supposed to use it to carry current.

I, personally would have no issue with using the ground as long as its tapped such that the current didn't run through the machine. I'd use one leg of the 220 and ground before I'd add a travel transformer to the equation. No heat or power usage involved.

Either way will work, however.
 

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Discussion Starter #5
Running current through a ground is a VERY dangerous proposition. Anytime you run current through a conductor a voltage potential is present. That means that any equipment that uses that particular "ground" has voltage on it. It may not be much, but it could have a higher value than you, which means if bad things happen - you get the current.
 

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I would not run current down the ground leg, I think I would set the power supply to run off of 220VAC by switching around the jumpers, that's easy enough..
 

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Aren't you still goingto need a neutral for the 110vac. I mean you have 3 conductors there already, right.

1- hot
2 - hot
3 - gnd

Won't you need a neutral to make the 110 work even if you use a step down transformer? I understand that the neutral is in all probability grounded in the breaker box anyway but....
 

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My understanding was that originally he was going to use one of the hots and the ground to get a 110vac source for the electronics. I think his power supply is set up to work off of 220 volts or 110 volts so he's got the option of just using the higher voltage tap on the transformer's primary winding, at least I think that's what's happening....
 
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