Mill is 3-phase 440v, I have 1-phase 220v - What kind of options do I have?

Thanks for clearing that up Walter. Now it's time for me to do a little "soul searching" and decide what direction I may take this over the next couple of years (to CNC or to not CNC...) :biggrin:. At least, with all the help you've given, I now feel that I can make a better decision as to what equipment I will need to purchase whatever I feel my machining future will bring. I need to make it quick though, I really, really want to fire up the mill. :cool:

BIG "Thanks!"

-Ron
 
Thought I'd provide a bit of an update. Well, I haven't done anything yet. :p Just funnin' ya! :biggrin: Actually what I've done is a little more "research" into my personal situation. You see, my "shop" is in a row of parking garages that I originally built with the intent of leasing the spaces out to tenants of my office building. There never was a whole lot of interest so that was kind of a bust. I did rent out one space to a cell phone company for some of their communcations equipment. That is why there is a 220v line and an HVAC system in one of the stalls. The cell company was bought out or went belly up and I was left with a stall that I couldn't put a car in but was good enough to set up shop.

Now, this garage/shop is roughly 80' from my office building on the other side of the parking lot. I had maybe a "flash of brilliance" (okay, okay, more like a blip on the radar :)) and so took a much closer look at the equipment I have set up in my building. I have 28 heat pumps, 3 circulating pumps, and a couple of units on the roof and it turns out that all the units are 208v 3-phase! I pulled up the site plan and electrical detail blueprints to see just how the 220v single phase was routed to my "shop". Turns out (at least on spec) that there should be a 1.5" pvc pipe from my office building out to my "shop".

So, in theory (and if it's within code) I'm thinking that all I should have to do is pull a 4-conductor wire from my equipment room in the office building through the pvc pipe/under the parking lot and to my little "shop"! :cool: The big question would be whether I can pull the 4-conductor through and at the same time leave the 220v single-phase line, or would that even matter? Could I just pull the 3-phase into my panel and run both the 220v and 110v single phases out of it?

What do you guys think?

Thanks,

-Ron
 
Ron

Now it all depends on which Load Centre Panel the run to the garage is taken from.

It is common practice in industrial complexes to run a 3 phase line to the building then take two lines from that to supply 208 Single phase and from one line to common to get 110 single phase. If this is your case then you may be able to just add or replace a breaker and replace the existing wiring, or pull the extra lines, to get 208 3 phase in your garage. Personally, I would pull heavy enough wires and put as large a 3 phase sub panel in the garage as I could, and from there use a combination of breakers to power the shop.

If however you have a seperate 1 and 3 phase supply and the existing conduit is coming from a 1 phase load centre, then adding a second run from a seperate load centre is not allowed.

I know it does not show up on my electrical diagram, but there are 2 single pole breakers in the 220V 3 phase panel, one for the refrigerated air cooler and another for the automatic tank drain for the air compressor, these two items only ever need to operate if the compressor is running anyways.

Walter
 
Walter,

Armed with what you said, I checked the load center the garage is fed from and sure enough there are some 3-phase breakers in there. Oddly enough there is also a 3-phase breaker marked "garage" but the the work "garage" has been crossed out and (after pulling the panel to look) it is not hooked up to anything. :thinking: Must be "destiny"! :biggrin:

Hmmm, now I've got to find a decent electrician to call... (Hate to call others to do work for me but this may be "one of those times". :rolleyes:).

Another question for you now, we discussed the TLCs and how they are integral to the systems you showed me. I'm still very much enamored with the idea (not quite obsessed though it may seem so :eek:) even if I were to go the direct wiring route. Is there a "free standing" device/monitor that will cut all three legs of the power if one of the phases drops out to protect the equipment or is that just plain over-kill?

Thanks very much,

-Ron
 
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Ron, have you measured the "220" in the garage? It sounds like you'll actually read 208V from bus to bus. A wye (aka star) transformer configuration for your service is actually 120/208 volts, with a neutral connection (grounded) where the three phase legs come together.

The next question concerns how many buses the panel in the garage has. They might have used a single phase panel (2 buses) connected to two of the three legs and the neutral. If there are three buses, check for voltage. You may already have 3-phase out there.
 
I'll measure the drop in the garage tomorrow and do a more thorough look-see at what I've got going on there.

Thanks much Hawkeye,

-Ron
 
I didn't have a lot of time to "play" today but I did drag out my DMM and poked some leads into the "220v" socket in my "shop". Each leg to the third slot (ground most likely) gave me a reading of 120v AC. Now, when I measured across the two hot legs they cancelled each other out so my reading was around 0v +-. I'm not real sure if that piece of info is any help but it still could be pulling from a couple of legs of a 3-phase. I'd need to pull the panel to see what kind of wire was sitting there, that'll be on tap for tomorrow. -Ron
 
Ron

There is no way that they will cancell each other out unless they are both from the same line.

If wired correctly the wide slot is neutral and the short slot is hot.

Hot to neutral on the same outlet is 120V.

Hot to Hot on two seperate outlets will be 0 Volts if they are both from the same supply (both blacks or both reds) and 220 V if they are from two seperate supplies, ie black and red wires. If it reads 208 V then it is taken from the two legs of a three phase circuit.

Walter
 
I agree Walter. Something doesn't seem quite right there. I just finished putting a new (rebuilt) power feed on the mill so I haven't had time to explore the power situation further. Wife is at church tonight so I will have some extra time after the office closes to take a look at things again (in theory anyway :p)

This is a good example of why you shouldn't just "plug something in" without knowing exactly what you have.

Thanks,

-Ron
 
Okay, had a few minutes so I grabbed my trusty screw driver and went down to the equipment room. I figured it would be best to see what is going to the garage/shop from this end.

First a couple "glamor shots" of part of my equipment room...


Main breaker panel, see the 1.5" pvc pipe out of the bottom of the left panel? That's the one that goes out to the garage/shop.


Shot of the "switchboard"


A couple of 3-phase motors running the pumps for the cooling tower on the roof.


Now, here is where the magic begins...


I circled where there are four wires feeding into the 1.5" pvc pipe. As you can see the plain "black" (B) wire and the "red" (R) wrapped on go to a 100a double breaker (207.5Vac across breaker). The third large "white" (W) wrapped wire goes to ground as the smaller green (G) wire goes to "earth" ground (if that's not the proper term, correct me. I was an "electronics eng." major not an "electrical eng." - didn't deal with power systems much).

That's what I have to start with,

-Ron
 
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