# 3-phase generators



## Southeast Power (Jan 18, 2009)

WronGun said:


> Pricing out a commercial generator for a pizza/take-out spot.
> 
> Very big price difference in single and 3-phase generators.
> 
> ...


Well, All you can do is give them a single phase generator and install a shunt trip breaker for that dough mixer.
Otherwise, set them up for a 3 phase portable and maybe they can get a rental when the SHTF.


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## active1 (Dec 29, 2009)

Many things are technically possible.
Reasonable is another thing.

Problem is the place was built on a 3Ph service.
So 1 solution would be to put all the loads and gen on say A & B.
With C providing power only for the mixer and anything else not wanted on the gen.
Then you have these problems:

1. May be you don't have enough space in the existing panel to not use C.
You could put a 2 pole breaker feeding an auto transfer switch then a 1PH panel.
Move all the loads except the mixer to the new 1PH panel.

2. Can you fit a 2 pole breaker in the existing main panel large enough for the loads or perhaps you need to tap in front of the panel. You may or may not need to get a service rated Xfer sw or add a service disconnect.

3. By not using C phase the load will be way off balance. Recalculate loads. It may require upgrading the service.

4. If your comparing generators in amps and not KW, the 1ph gen would need to be larger than the 3ph. Do the load calcs and gen sizing in KW.

5. You are changing them from a 208v to 240v when the gen runs. Some loads may be fine with either. Others may have a wired option, but not change on the fly. You would need to go thru everything. HVAC, hood, freezers, coolers, etc. to verify it wont smoke by you trying to same an owner some money.

Is it possible to have a Xfer switches go from 3ph to 1ph by shorting say B & C on the generator side? Mayby? I never seen it. In that case the generator would need to be sized much larger as B would have about 50% more load (B & C) then A. I would guess the 1ph gen would need to be 50% larger, but again it would go back to actual calcs. I'm thinking if one of the contacts stuck it would short out the B & C phases. 

To sum it up, by the time you calculated and adjusted for the imbalance in sizing, I wouldn't think it would be worth going down this path.


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## WronGun (Oct 18, 2013)

active1 said:


> Many things are technically possible.
> Reasonable is another thing.
> 
> Problem is the place was built on a 3Ph service.
> ...




It seems it may be less of a headache to just offer 3-phase portable and standby


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## micromind (Aug 11, 2007)

Supplying a 3Ø panel with a single phase generator will not be easy. If nothing else, the single phase transfer switch might not be able to handle 208. 

The cost of this may very well exceed the cost of a 3Ø gen. 

Further, in my experience, you get what you pay for. The inexpensive single phase gen may or may not be as reliable as the more expensive 3Ø one. It seems that there are a fairly large number of inexpensive home type gens that are pretty much trash these days. 

Personally, I would not even consider installing a single phase gen on a 3Ø service.


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## Southeast Power (Jan 18, 2009)

I was ASSuming it was a Delta service.
OP.
Do you have 120/208 or 120/240??


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## splatz (May 23, 2015)

WronGun said:


> It seems it may be less of a headache to just offer 3-phase portable and standby


See why the three phase generators cost so much - because they're worth it


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## nrp3 (Jan 24, 2009)

What size generator are you trying to sell? In air cooled there is a price difference, don't see much price difference in liquid cooled. Price difference in transfer switch, maybe double.


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## telsa (May 22, 2015)

A 3-phase alternator is significantly cheaper to design and manufacture than a 1-phase alternator of the SAME kW.

So I'd question your original 'take' on the price shift.

If the customer has a 3-phase Service... stop over thinking this... he needs a 3-phase SDS.

( ie Gen-Set )

Now, you decide just how many loads can he shed.

For a COMMERCIAL account, you'll find that he can't shed ANY loads.

He wants to operate his BUSINESS as if he's still on Poco power.

And...

He has the BUDGET.

Equipment prices that freak you out -- don't freak HIM out at all.

What freaks him out: being totally SHUT DOWN until the Poco comes back up.

That could -- and often does -- BREAK an enterprise.

&&&

Do you have ANY idea of how much $$$ your customer can make while he's up and running and ALL of his nearby rivals are shut down ?

Do you ?

He could well afford thirty-installs -- that's what.

&&&

Your job, as EC, is NOT to scrimp and save on materials outlays.

That's the fastest way to the poorhouse.

Your job, as EC, is to elegantly install right-sized Listed gear in super quick-time.

That is really it.

Value-engineering one-off projects = fastest way to bankruptcy of the mind.

Yeah, you'll fry your brain. These will prove to be one-of-a-kind projects -- so that NOTHING you've achieved (conceived) can be put to use again.

Get it ?


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## frenchelectrican (Mar 15, 2007)

WronGun said:


> Pricing out a commercial generator for a pizza/take-out spot.
> 
> Very big price difference in single and 3-phase generators.
> 
> ...



Wrongun.,

You did not mention if this place did have actual single phase or Three phase service .,, 

If it did have three phase then what format it is ?

If that place did have three phase I would stick with three phase unit than try to mess around with single phase generator with three phase system in there.


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## splatz (May 23, 2015)

I'd present the three phase generator and transfer switch as the right way to do it and the first choice. I might mention pulling the covered loads to a separate subpanel and installing installing a single phase generator for that panel but I think you'll see that that's a break even at best and you'll still want the three phase generator.


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## nrp3 (Jan 24, 2009)

I sold a 48kw 3 phase unit this week and even though we aren't backing up any 3 phase loads, it didn't really occur to me to go single phase. No real room for another panel anyway. Carrying most of the office and lighting, the only three phase loads were a couple of condensers which they won't likely need. It was the computers, servers and printers, heat, etc.


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## MikeFL (Apr 16, 2016)

Are they looking to be open for 2 weeks when there is no power or are they just looking to sustain momentary/ short duration outages when POCO service goes down? A 3 phase UPS may be an option if they cook with gas.

Another thought, can that mixer be set up for single phase? Or can they get another mixer and sell that one? Or covert it? That may be cheaper than a 3 phase genset.

I priced 3 phase gensets during Hurricane Irma and they were many times higher cost than single phase. I even have a buddy who owns a factory that makes gensets and I still didn't get one.


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## nrp3 (Jan 24, 2009)

What brands were you looking at?


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## frenchelectrican (Mar 15, 2007)

MikeFL said:


> Are they looking to be open for 2 weeks when there is no power or are they just looking to sustain momentary/ short duration outages when POCO service goes down? A 3 phase UPS may be an option if they cook with gas.
> 
> Another thought, can that mixer be set up for single phase? Or can they get another mixer and sell that one? Or covert it? That may be cheaper than a 3 phase genset.
> 
> I priced 3 phase gensets during Hurricane Irma and they were many times higher cost than single phase. I even have a buddy who owns a factory that makes gensets and I still didn't get one.


I think there were some backlogged on some X sized units but larger one is not a issue but smaller one like 20 or 30 KW 3 ph units that I am not confirmed on that.


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## nrp3 (Jan 24, 2009)

Was wondering if these prices may be on "industrial/NFPA 110" capable units?


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## MikeFL (Apr 16, 2016)

I don't remember which brands but I think I was just looking for 20kW to run some a/c. Nothing in stock from Miami to Tampa and 1 week lead times. IIRC it was around $9k and a week to get it.


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## nrp3 (Jan 24, 2009)

Going from aircooled 20kw to liquid cooled 20kw is about a 100% difference. Three phase aircooled to liquid cooled still a big jump though not as much.


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## active1 (Dec 29, 2009)

Don't sell a low end air cooled 1 ph resi generator.
Also if you haven't noticed, sometimes the KW ratings are in propane.
With natural gas being a lower rating because it makes less power.
So a 20kw could only be a 18kw on NG.

It's a good point about being the only place open with food.
If I came home and had no power I would go there too.


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## Bird dog (Oct 27, 2015)

IMO go with a Cat (Olympian, FG Wilson), Cummins or Kohler. Stay away from Generac.


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## Southeast Power (Jan 18, 2009)

I guess the OP made a decision.


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## chicken steve (Mar 22, 2011)

splatz said:


> I'd present the three phase generator and transfer switch as the right way to do it and the first choice. * I might mention pulling the covered loads to a separate subpanel and installing installing a single phase generator for that panel* but I think you'll see that that's a break even at best and you'll still want the three phase generator.


I've gone that route. 

It really depends on the number of '_critical loads_' VS portable KW required for it

The only other consideration was _introducing_ a 180 vector into a (normally) 120 _supplied_ vector ....

~CS~


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## WronGun (Oct 18, 2013)

I’m actually going to start this estimate tonight...

I’m sticking with 3-phase

I’m going to give him a portable and standby option. 

The only heavy power draw in this place is the dough mixer, hood, microwave. Everything else is gas. 

The dough mixer is the only 3-phase draw. 

In this area when power goes out which is often , it sometimes lasts 3-4 days which just happened. A business like this can easily lose 1500-3000 in sales per day.



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## LGLS (Nov 10, 2007)

WronGun said:


> I’m actually going to start this estimate tonight...
> 
> I’m sticking with 3-phase
> 
> ...


Refrigeration?


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## frenchelectrican (Mar 15, 2007)

WronGun said:


> I’m actually going to start this estimate tonight...
> 
> I’m sticking with 3-phase
> 
> ...


If portable there is two option you can go is use manual transfer switch or automatic transfer switch but you will need that portable generator have a capable haveing remote start aka two wire start/ stop connection 

how big the service this place is ? 

Lawnguysparky guy did mention refridgeation the med to larger walk in or larger cooler typically be on three phase too so that is something else you need to check it.


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## WronGun (Oct 18, 2013)

frenchelectrican said:


> If portable there is two option you can go is use manual transfer switch or automatic transfer switch but you will need that portable generator have a capable haveing remote start aka two wire start/ stop connection
> 
> 
> 
> ...




It’s a 150A Service 

Small 2 door cooler 


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## frenchelectrican (Mar 15, 2007)

WronGun said:


> It’s a 150A Service
> 
> Small 2 door cooler
> 
> ...


the small two door cooler typically are at 120 volts on your side but some models are wired for 208/240 volts as well.

that is pretty small service so did you do the load demand caluations for sizing the generator yet .


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## WronGun (Oct 18, 2013)

As far as Receptacle goes looks like I’m using the pin and sleeve setups ? 

I’ve used these on phase converters , Im online trying to search 3-phase Gen parts


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## frenchelectrican (Mar 15, 2007)

WronGun said:


> As far as Receptacle goes looks like I’m using the pin and sleeve setups ?
> 
> I’ve used these on phase converters , Im online trying to search 3-phase Gen parts


Try to see if you can get them in 5 pin arrangement due ya running full boat from the 3 ph generator.

I am sure alot of them do make in 5 pin sleeve type but what size ya looking for?


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## WronGun (Oct 18, 2013)

frenchelectrican said:


> Try to see if you can get them in 5 pin arrangement due ya running full boat from the 3 ph generator.
> 
> 
> 
> I am sure alot of them do make in 5 pin sleeve type but what size ya looking for?




I honestly don’t know yet. 

I’m snowed in today so I’m trying to get educated on this... researching the electrical setup and generators 


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## frenchelectrican (Mar 15, 2007)

WronGun said:


> I honestly don’t know yet.
> 
> I’m snowed in today so I’m trying to get educated on this... researching the electrical setup and generators
> 
> ...


Ahh ok as long ya not busy making snowman .,, hehehe.,,

anyway check the info on 100 amp size I am pretty sure there is 150 amp size but if you get into 200 amp size the price will actually knock ya off from the chair.

If you did the load demand caluation and if you can get under the 100 amp plateu then you should be fine with common 100 amp pin sleeve unit.


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## WronGun (Oct 18, 2013)

frenchelectrican said:


> Ahh ok as long ya not busy making snowman .,, hehehe.,,
> 
> 
> 
> ...




Portable or standby are both expensive options. 

It’s seems they don’t even make manual transfer switches for this setup..





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## WronGun (Oct 18, 2013)

I don’t see him spending 13-15k

It seems the most cost effective option is to install a single phase sub panel and do a portable Interlock setup....

I’ll give him the option for minimal backup Operation. Lights , cooler, micro, pilots for his gas appliances , etc. 

He does have (2) 208V appliances 


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## frenchelectrican (Mar 15, 2007)

Wrongun .,

No they dont., and that will be a seperated item.

I dont recall there was a someone did make a manual transfer switch with pin sleeve connector on it.

I think Croise Hind ( spelling ) or Arrow Hart but that more like looking for hen teeth .,,


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## WronGun (Oct 18, 2013)

This is getting to be a pain 

I’m just going to offer the 3-phase generator 

Maybe an option to set up a generator power to the entire Building 

It’s a small plaza with 6 tenants 


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## nrp3 (Jan 24, 2009)

It can be for sure. Sometimes just figuring where to plant your equipment can be a nightmare. Then you have to tie it in to whatever nastiness already exists. Don't sell yourself short on time planning and time for multiple inspections. Know for certain what voltage you are working with and what fuel type you are using. In some cases, above a certain KW, its ordered as natural gas or propane, not convertible. Be certain what you are getting, because once you order it, you own it. More than a few people have bought 120/240v 3 phase when it should have been 120/208, etc.


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## Bird dog (Oct 27, 2015)

This may have been pointed out, but, if they go the portable (rental) option will they be able to get a genset when they need it?


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## telsa (May 22, 2015)

A Commercial Service would be CRAZY to depend upon a temp hook-up.

The businessman's advantage to having truly uninterruptable power is VAST.


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## telsa (May 22, 2015)

1) First decision is sizing.

2) The scheme should be automatic transfer during black-outs.

This entails block heaters, etc.

Don't kludge this up with power cords and manual transfer switches: too complex for the customer.

You're dealing with a baker// cook -- or whatnot -- not a power engineer.


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## nrp3 (Jan 24, 2009)

So yes don't forget block and battery warmers. Also, if you're on the 17 code, they are calling for additional shutdown switches as well. An accessory on all brands from what i've seen.


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## active1 (Dec 29, 2009)

What you pictured, the Appleton isn't the most durable IMO, plastic lock ring, and think it can be had at 68a or 100a.

For anything over 100a cam locks with separate conductors is the way to go.
Reasonable priced, easy to terminate the wire, easy to plug in.
100a you could go mini cam.

Crusoe Hinds makes some nice stuff that will last. Trouble is a set would cost a lot for the small job your doing.

There's another 100a connector, Veen, I think. PITA with snap rings, and half the time people cross thread it when plugging in. A bit pricey.

That said I can't picture a customer rolling out a 3ph 30kv, doing hook-up and keeping fueled during power outages. Herd one problem with small gasoline or diesel gens are keeping them fueled when the area's dark. Going across town here when the stop lights are out is on par with figure 8 racing.

Natural gas, auto start is the way to go.

What about a hood system for the load.


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## nrp3 (Jan 24, 2009)

I've driven in Vegas quite a few times. Can't imagine what its like without the traffic lights working. Be like playing Frogger... I haven't sold any diesel units largely because I'm concerned with the fuel being kept clean and the customer not doing it. Also I'm not a diesel mechanic. I'd probably hand the maintenance off to one of the large industrial dealers. Having a large portable like that will require that someone exercises it and maintains it. Customers half the time don't do that with small portables and wonder why they don't work when they need them. Either propane or natural gas standby's take care of a couple of those issues. Still can't ignore regular maintenance, but probably a better way to go.


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## WronGun (Oct 18, 2013)

I didn’t even bother writing up
A formal estimate. I just sent him an email with rough pricing. 

I honestly think he was looking at portable resi generators to get him by. 

Sometimes if I feel a customer is completely clueless I just send an email With ballpark and get a feel if he is serious and really wants me to break it down with calculations. 

I gave him 3 options 

Option 1 - 13k-15k

Option 2 - 15k -18k

Option 3 - 45k-50k


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