Powering from a generator

Most posts I see on this devolve into phase converting, and I really wish that was an option here! Otherwise it seems to be for larger multiple machines at once kind of shops. So yes, my use case is rare.

I bought my house because 3 phase lines are a few feet from my property (like 6 feet). I figured there was no way 3 phase power could cost a lot to put in. Boy was I wrong! Rocky Mountain Power quoted me "tens of thousands" for three phase, then then recommended larger single phase service. So they offer 400A at $10k, and 600A at $14k! That's not getting the panel upgraded, or wires to the shop. That's for them to run a cable 50' in the air, or run a cable 50' in the air and install a current transformer. (Oh, and the part they didn't say, but then they'd want to charge me commercial power rates). I don't plan on being any sort of job shop so that's ridiculous. If I was, I'd get a commercial property! (and pay commercial rates!)

Ok, so power company rant over, if I want to power a machine, I'll have to generate the electricity. It sucks, but I also bought enough land that a generator in a decent enclosure should be ok for noise levels.

I guess I'm mainly looking for people's experiences with generator sizing, surge capacity, etc. One machine makes this quite possibly the worst case scenario. I've heard double or triple the motor power used to set the generator's "operating", not surge capacity, rating. This confuses me a bit, because the surge capacity is what I'd think should be looked at. Then again, I don't want a generator that stalls trying to start the machine. I called the local haas dealer and they said one step up (like a 30KW instead of a 25 for a 30HP/22.7KW machine) is probably all that's needed, and that its easy to pull the computer off the generator and onto landline power (though I can't help but wonder about ground issues with that thinking about it a little more).

Anyhow, I'm looking to see if anyone out there has run a single machine at a time from a generator and what they found their sizing needs to be. I don't want to waste fuel with a large displacement generator running at 0.1% of its rating, but don't want to stall out either! Further, I'd like to run the generator from my natural gas line if possible, but there's no way I'm fueling a 60KW generator from the house lines! If that's a firm requirement, I'll have to go with a propane tank! (I'm not even sure if it would be quiet enough to run without a noise issue!

You'll go broke feeding that genset vs a converter.

Not sure why a phase converter of some sort is "not an option".

What size is your single phase service? Not the box rating only, but the local pole transformer if you can find out. Most will be at least 25 kVA, but some may be as small as 15kVA

Rocky Mountain Power in Fairfax, Virginia??? Wha????

More to the point - Did I miss where you stated what sort of power requirements you have or will expect to have? "I don't plan on being any sort of job shop..." So, what DO you plan on being?

And yeah - why u no want converter?

Corry said:

I called the local haas dealer and they said one step up (like a 30KW instead of a 25 for a 30HP/22.7KW machine) is probably all that's needed,

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I ran on twin one-hundred kay dubs active, two spares, a 60 kay-dub, a 30, a 15, a 5 - all
Diesels - plus a 3 Kay-dub (MOGAS) 24 X 7 for 12 months.

You "may" be able to soft-start a 30 HP spindle off a 30 kay-dub. We sweated bullets to start 100 HP off 100 Kay-dub, so 40 Kay-dub, minimum, 50 or 60 preferred is what I'd use.

Smart thing, BTW, was to move house and JF LEAVE all that shit at Long Binh, RVN, where the US taxpayer was providing the fuel, spares, maintenance, Diesel tankerage, mechanics, and whole new gen sets ever now and then.

Unless you can cut the same deal as to "who pays?"

You may have also picked a location better suited to goat farming or cultivating green stuff than running that Haas!

The NON-RECURRING Utility hook-up fees you quoted, BTW?

Right cheap, actually. Price the TWIN gensets you'd need for even a fraction of the reliability of the grid.

Ga-ron-tee that either of propane or #2 Diesel will set you back more in any given year than commercial power, too. Five to ten times as much, typically. You got to pay for maintenance, lube & filter changes, amortize the gen set(s) so as to roll-in new ones ever so many years. Tankage degrades and needs money. Permits as well. Diesel fuel needs filtered to death, even preserved and 'polished'.

You picked a 3-P capable site? First machine has a 30 HP spindle?

Pay up, build-out, hook-up, use 'mains' 3-Phase for it and be happy you even have the option.

TANSTAAFL

I suppose another question that is very important should be asked...... What is the LOAD?

You mentioned Haas.... and 25kVA, and that you are not a commercial shop.... but the actual load was not mentioned.

Converters vary, a rotary might not be good for you, but a Phase Perfect of the correct size will do anything needed, so long as you have the input power available.

As above... plus.. the waveform from a 30kva generator generally sucks and your cnc might barf. There are generators that put out an excellent waveform, but good luck try to find a small one at a decent price.

A 30hp Phase Perfect on a 200amp single phase supply will be... well... "Perfect".

JST said:

I suppose another question that is very important should be asked...... What is the LOAD?

You mentioned Haas.... and 25kVA, and that you are not a commercial shop.... but the actual load was not mentioned.

Converters vary, a rotary might not be good for you, but a Phase Perfect of the correct size will do anything needed, so long as you have the input power available.

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His 1-P is bound to be "marginal" already for a converter, and we don't have lighting, other machinery, or HVAC, or....

A mere $10K for a 3-P hookup? Gots to have entrance panel and distribution load-centers REGARDLESS.

Got just about $10K in my MEP-803a, what with fuel tanks, fuel "management", automatic and manual transfer switches, load center switchgear, wire and conduit, supplementary cat converter/soot traps, etc.

All for an emergency/standby AND NOT "day-job", nominal 10 KVA, near-sea-level 'actual' 12 KVA, 15 KVA peak, and most of it bought USED at that?

He needs double and more that gen set, and preferably turbocharged, not normally-aspirated, as well if 'wet stacking' when under light load is to not overly shorten its useful life between overhauls.

Go with mains 3 phase - try to manage the peak loads intelligently - and JF go make chips.

Or JF don't buy the Haas.

Kay-Dubs?
Bill D

Bill D said:

Kay-Dubs?
Bill D

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Because, somehow, it's easier than typing "KW". Kay-Doubleyous=KiloWatts

Bill D said:

Kay-Dubs?
Bill D

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Conversation and deeply-ingrained HABIT, rather than typing.

"Dub" as in Dubyah or "W".

GI's tend to be too lazy to say "Kilo Watt" let alone the more 'correct' "Kay Vee Aye" and even less "Kilo Volt Amperes".

Economy thing.

We had learned to make space for some artistic variation or another of "f**k" about every third word.

Your missing a really big point, powering a 25Hp hass with a generator is nothing like sizing a generator to line start a 25hp pump. The hass and nearly all spindles on cnc's run through VFD drives of one style or another, this means start currents little more than double what the running current is, unlike line starts of a similar motor that will often pull over 6x name plate current. You don't need a generator 2x the size, most are at peak efficency at about 70% load, and surge is what they can do to start motors and such so for a 25Kw Hass personally i would be looking for a 40-50Kw generator unless you want to power other things in the future, even then you could probaly run at least 2 25Kw Hass of the same 40Kw constant rated generator with spare capacity, its going to be a rare day that a hass is going to be pulling full name plate power and a near certainty 2 will never both spike at the same time.

Have only been around diesel generators, my understanding, natural gas put out less HP for a given displacement hence you go bigger displacement wise yet again.

IMHO for 10K your not going to save anything going generator and it will cost more in the long run.

As to industrial power rates, well that is what your using and wanting, hence why do you not expect to be charged for it? IMHO you need to talk to some real competant generator sizing enginers and get some real numbers if your not just going to get your head out of your ass and get mains dropped in. Remember just because the wires are there does not mean the power company have the transformer capacity going spare to feed you too!!

Lots of sensible comments so far. I can't imagine running my shop on a generator over a phase converter. The only thing I would add is that you could not give me a gas generator (natural or propane). All the ones I have seen run at 3600 rpm and are screaming pieces of crap compared to the diesels I have seen, all of which run at 1800 rpm and you can't even hear that they are running from more than 50' away. About 10 years ago I bought a 25kva Wacker G25 for backup and it has been great. Not a bad thing to have around. Iron planet has some auctions coming up of similar trailer mounted machines in the 25-100kva range and bigger.

If Stable frequency and voltage control are important you will need larger rather than smaller. I would expect minimum 60 KW.

WHHJR said:

If Stable frequency and voltage control are important you will need larger rather than smaller. I would expect minimum 60 KW.

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Don' wanna go TOO big. Adama's comment on 70% isn't just about the fuel/thermal efficiency 'sweet spot'. Run a Diesel too long at too-light of a load, it can 'wet stack'. Not an issue when same-day, same-shift sees heavier loads. BIG issue if NO days do for weeks and months on-end.

If it was 10k for 3 phase I'd go for it. They said 10's of thousands. Not an actual quote, but I asked if it was 20k and he said higher. Assuming $30k. That's a bit steep. 10k is for 400A single phase, just running the wire from the pole through the air to my service box. 10k...for that...that I'd never be able to recover...

Haven't updated my profile, I'm now in Salt Lake City. Fairfax was hot, humid, and expensive .

Single phase service - no idea what the pole says, but it's a 200A. So it's pretty much upgrade or don't run the machine.

I'm not planning on being a job shop. If I ever do, I'll move the shop to a commercial building with 3 phase already there. So feeding a generator won't cost me much, unless it's a large displacement engine running at idle all the time! The way I see it, I can sell a generator. I can't sell power upgrades that few else want.

Natural gas has less energy yes, so for a given displacement, you expect 10% less hp. Also plenty of them that run at 1800rpm now. Important if the head is pulling max energy from the engine.

Generator sizing experts: that's what I had hoped to find here!

Soft start: I asked the local hfo, and they said there is no soft start. They also said they thought going just a generator step up would be fine. He wasn't an expert though...I still wonder, how would they be controlling spindle speed so precisely without a vfd? And if there's a vfd, shouldn't soft start be possible? If I had a machine to take apart I could tell for sure

I think that's all of the comments addressed...

Corry said:

Soft start: I asked the local hfo, and they said there is no soft start. They also said they thought going just a generator step up would be fine. He wasn't an expert though...I still wonder, how would they be controlling spindle speed so precisely without a vfd? And if there's a vfd, shouldn't soft start be possible? If I had a machine to take apart I could tell for sure

I think that's all of the comments addressed...

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Not really "all". You have another thread running on used Haas, etc.

Now - I am not any sort of "CNC Expert". Quite the reverse.

But a "business" in general & Finance in particular guru, factory-build-out AND operation included?

Very much so.

On which basis, I have to tell yah, there doesn't seem to be the least indication of a viable biz plan, nor - after six MONTHS of trying to grok the diff between generations of Haas VMC's, even much focus or drive of any kind towards a clear goal.

That pattern, if I am not serious-wrong about it, is a sure-fire way to turn money and dreams into debt and nightmares.

Lots of idle CNC spindles hungry for work around. CAD/CAM/CNC has made work very "portable", ergo highly competitive, and the resulting margins are anywhere from lean to NEGATIVE for lots of folks. Orders are migrated by lean buyers over a gain of a few cents per piece, or who will wait longest to be paid at all.

If you BELIEVE you have a "product" rather than planning a "Job Shop"?

"More better", then, that you contract at least a proof-of-viability "pilot" lot to some of those idle, "hungry", spindles, rather than adding yet-another one of your own.

If you are looking at 25-30 HP CNC spindles as a "hobby"? Then the cost of power is all part of that.

In your "play-toy" budget?

Or NOT?

Might it be in your better interest to just go and dream a different dream?

Corry said:

If it was 10k for 3 phase I'd go for it. They said 10's of thousands. Not an actual quote, but I asked if it was 20k and he said higher. Assuming $30k. That's a bit steep. 10k is for 400A single phase, just running the wire from the pole through the air to my service box. 10k...for that...that I'd never be able to recover...

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Have you spoke to another person at the power company? They reason I say that is sometimes they are ways around things and the particular guy you have been dealing with may not be in the know or just not interested in helping a guy out.

My power company has a program that will upgrade you for FREE up to a 600 amp residential service. That includes transformer, Meter, and cable to the new meter. But you can only have one meter on the property. I had no idea this was a option so when I called to get a service in my new shop I originally told them I wanted a separate meter on the building. Luckily the guy I was dealing with told me about this option. He said he would be happy to quote me a separate meter but I would be on the hook for the transformer and would be bumped into commercial rates. So no brainier there but if he wasn't aware of the upgrade program or just didn't care I would be getting sick about buying a transformer.

For some reason 600amp residential services are becoming popular around here.

Bigbore050 said:

For some reason 600amp residential services are becoming popular around here.

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Electric Wok's, maybe?

Mega McMansions..... Everyone seems to be building and buying them.

Monarchist said:

Don' wanna go TOO big. Adama's comment on 70% isn't just about the fuel/thermal efficiency 'sweet spot'. Run a Diesel too long at too-light of a load, it can 'wet stack'. Not an issue when same-day, same-shift sees heavier loads. BIG issue if NO days do for weeks and months on-end.

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We did plant annual outages for electrical upgrades for about 15 years in a row. There were anywhere from 40 to 70 generators brought in to maintain various loads. It was proven numerous times (the hard way)that when voltage and frequency were critical (process control computers etc.) about 50KW is the minimum that would work properly. I merely presume that a CNC machining center would be such a load....

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