Power Issue with my Machine Shop

I started a small shop in a 900 sf building I have on my property in the country. Before I moved in the prior owner had a woodshop, the
building has its own power and gas. 11 months ago I bought a Bridgeport Milling machine with a phase converter. The power off the transformer is shared with 2 other neighbors. Everytime I turn on my mill there is sudden dimming of the lights and it did it with the neighbors lights in there house too. I called my power company and they came out and changed the transformer from 5 kva to 25 kva. I still see little bit of a power drop in the neighbors lights, I work at night and now that it is getting darker out I can see the issue. Now that I am getting busier now and getting a lathe in 2 weeks I am wondering if I can get my power on my own transformer, do you think it will be expensive or should pay an electrician to upgrade my power to 200 amp service which would make the power company come out and put in even a bigger transformer? I have a 100 amp service and all I have is a mill and then I am getting a lathe that runs on 220 single phase.
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I have a 100 amp service and all I have is

Get things setup on real 3 phase and move on.
Bob AZ
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You've never lived in the country have you?
Real 3 phase power could be many miles from his house.
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Yes I have. But the OP said they replaced the transformer with a 25KVA. That says 3 phase is distributed nearby to me.
Bob AZ
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Bob AZ wrote:

Not sure where you come up with that, perhaps something unique to the utility in your area. I've seen numerous 25kva transformers far from any three phase feeders and that's in two different states.
Pete C.
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Bob AZ wrote:

A 200 A service at 240 V delivers 48 KW. Throwing in even a small allowance for power factor brings it to 50 KVA. So, the 25 KVA transformer is barely able to supply the OP's OWN 100 A service alone. Putting 3 houses with 100 A service on one 25 KVA transformer is really marginal. I find it hard to believe that 3 houses were running off one 5 KVA transformer. You could only get about 20 A from that small a transformer. It would most likely have a 25 A secondary breaker on it. If anybody has an electric range, dryer or central air, it would pop that breaker real fast.
I have a 200 A service, and my OWN 50 KVA transformer on the pole. All single phase, for sure. 25 KVA is by no means a special or industrial level of service.
Jon
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Thats what NYSEG told me and when that transformer was on the lights really dimmed out bad, I would say 40 percent when I turned on the mill. The 25 kva did help and isn't as bad. Maybe the soft start maybe an option. They also told me if I wanted my own transformer I would have to pay for it.
Thanks
Jon Elson wrote:

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Jon Elson wrote:

You have to realize a few things:
1) A "200A" electrical service is not allowed by code to be loaded to 200A continuously, and in the real world will spend most of it's time with a load under 20A.
2) Utility grade transformers are rated to handle a 100% overload (i.e. 50KVA on a 25KVA transformer) for 24 hours without damage. This is not the same as regular dry type commercial transformers.
3) There are load diversity allowances since the three houses are quite unlikely to max out their services at the same time.
I share a 25KVA transformer with one neighbor. I've not noted (nor has my UPS's log noted) any power dips even when I'm using my large TIG welder that pulls close to 100A at 240V. Not even the slightest blink when starting the rotary phase converter for my Bridgeport.
If you're seeing a significant drop from a small load like a Bridgeport, *do not* waste your money paying for a new dedicated transformer, the problem is with the primary lines feeding your area, not the transformer.
Pete C.
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On the other hand -- yesterday I helped a friend install a 20HP rotary kompressor (just a giant vacuum cleaner motor) for his NC router. During inrush, it pulls about 90A on PH1-PH2 (measured at the service side of his rotary converter), and about 80 on the manufactured phase.
The incoming service drops to 203V across PH1-PH2 (at the utility side of the main) during the startup inrush.... too low to meet specs, but the power company says that's all they're going to provide. Our local tarrifs call for a minimum of 210V at 100A. They don't give a damn if it meets spec. or not, so long as most residents don't complain.
He's on a 25KVA can shared between two homes.
LLoyd
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"Lloyd E. Sponenburgh" wrote:

Get a power line logger or dig scope and appropriate probes, document the issue and send the documentation certified mail to the utility and cc'd to the utilities state regulatory commission.
Pete C.
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Check the regs carefully before making too much noise. In this area the power company can refuse to supply power to single phase motors larger than 5HP (or maybe it's 10HP). I've never heard of that rule being enforced, but I wouldn't want to be in the position of demanding that the power company deliver a specified voltage to a load when they have the option of simply refusing to feed it at all.
Ned Simmons
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wrote:

===========Actually why should he do anything? It's not his problem. If the neighbors have a problem let them take it up with the electric company.
Unka' George (George McDuffee) .............................. Only in Britain could it be thought a defect to be "too clever by half." The probability is that too many people are too stupid by three-quarters.
John Major (b. 1943), British Conservative politician, prime minister. Quoted in: Observer (London, 7 July 1991).
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On Tue, 14 Nov 2006 15:43:19 GMT, "Lloyd E. Sponenburgh"

Do a little looking and you can easily find out where the voltage drop is hitting the system - He may have a 200A Service on the house with 3/0 Copper going up to the weatherhead, which is fine and dandy. And the 25 KVA can is probably enough...
But if the power utility is feeding the house with #6 Aluminum triplex drop wire with a #6 ACSR support strand neutral, and the secondary leads between poles are #2 AL for two or three spans to the transformer, there's where you are getting all the voltage drop.
You may have to do some serious screaming to the utility regulators in your state, but you can get the utility to clean up their side.
I'm finishing up a service upgrade now, and I swear they've got #8 AL drop wire for the old 100A service.
--<< Bruce >>--
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"Bruce L. Bergman" wrote:

Think they were trying to both provide power to the house and provide mood lighting to the yard from the glowing drop?
Pete C.
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wrote:

That, and they were looking to make their pool parties more exciting if and when the service drop ever broke - the old drop wire routing for the C. 1960 house goes right over the C. 1965 swimming pool...
I've requested a mid-span attachment when they upgrade their half, let's see if SoCal Edison will do it right the first time.
--<< Bruce >>--
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I know, I wish I could...
Bob AZ wrote:

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Carbonite wrote:

Unless you have a real money making business, you *do not* want "real" three phase power. Not that real three phase power isn't nice to have, the problem is that in most areas three phase commercial service is peak metered so you'll get really screwed paying for the peaks from your welder even though most of the time there is hardly any load. Much cheaper to use VFDs and RPCs on KWH metered single phase service.
Pete C.
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My power company told me the min cost per month for 3 phase would be $500. And that is if I didn't use a watt. I don't think most hobbist can pay that
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that
Really? Are you sure you didn't misunderstand?
When I put 3 phase in my building, they charged me $450.00 per month for a year to cover the cost of a new transformer. After that, they dropped it back to normal prices. Mine is usually under $200 per month.
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Pacific Greed and Extortion told me much the same.
Gunner
Political Correctness
A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
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