Need some help picking a generator for single-phase and 3-phase use

[HDN]

My wife and I have talked about getting a back-up generator to provide single-phase power our house during a lengthy outage. Also, I want a generator to provide 208V 3-phase power for my ~1950 5-horsepower Federal Signal Model 5 air raid siren, and any other sirens that I might acquire (a Thunderbolt siren system will require 15 kW at the bare minimum). Who knows, maybe when I get my forever home I'll want to run some beefy electric motors for other stuff

I was originally considering a trailer-mounted MEP-805 for this duty, but some short research seems to indicate that the unit can't easily be wired for single-phase house power. Maybe I'm missing something?

Does anyone have any recommendations for what I should be looking for? Is there a civilian genset I should consider instead?

 

[Light in the Dark]

Well what are your realistic 1PH loads, and what duration do you intend on running them for? Same for the 3PH requirement.

I think you need two different solutions, based on the HP/KW ratings for your 3PH needs (as the KW ratings on a genset required to run those items, would be hugely overkill for 1PH needs). Duty time I think would be the biggest driver in this decision.

 

[flyfishtrailer]

The Gen set addiction states you can't have just one so, start with an MEP803 and then, when you need more KW, get something bigger.

 

[MatthewWBailey]

My wife and I have talked about getting a back-up generator to provide single-phase power our house during a lengthy outage. Also, I want a generator to provide 208V 3-phase power for my ~1950 5-horsepower Federal Signal Model 5 air raid siren, and any other sirens that I might acquire (a Thunderbolt siren system will require 15 kW at the bare minimum). Who knows, maybe when I get my forever home I'll want to run some beefy electric motors for other stuff

I was originally considering a trailer-mounted MEP-805 for this duty, but some short research seems to indicate that the unit can't easily be wired for single-phase house power. Maybe I'm missing something?

Does anyone have any recommendations for what I should be looking for? Is there a civilian genset I should consider instead?

Those are 2 totally different applications. Your house is 240/120 1phase. As a PE in your state, I'd recommend a nat gas or propane duel fuel unit. ie Gas/propane. There are a few different makes out there that are totally enclosed. Generac and Westinghouse are good newer brands with warranties.
Key questions:
1. Do you have electric heat?
2. Do you have central AC or room units or heat pump?
3. Do you have gas kitchen range or electric?
4. Do you have well or city water?
5. What is your daily kwh usage(look at electric bill)

People always go overkill on kW which is wasteful. A typical house can run indefinitely on 5-7.5kw unless you have all electric on the first 4 above. Your "demand" is the defining parameter.

For long term house power, don't use a trailer mounted unit! Grounding and bonding can be major problems with those when interconnecting to a building, and you don't want to shock your spouse. If you spend more than $1, spend it safely and so that you can gain the added home value if you eventually sell. Get an automatic transfer switch so the operation is seemless.

Typical military gens are for field, temporary power, not for connecting to buildings. Use the MEPs for the sirens and esoteric 3 phase stuff by connecting that stuff directly to the trailer gens.

PM me if you need more specific info. I don't charge the fine folks on here unless I have to incur specific liability by issuing drawings or similar. Free professional advice is my way of giving back.

 

[HDN]

Thanks for the responses so far everyone! @MatthewWBailey I appreciate your offer - I may send you a PM at some point

The responses here reminded me of another idea I had. I want my next home to have a solar array with battery storage, and condition the place with cold-climate heat pumps. The solar-battery part probably won't happen right away because those systems are ridiculously expensive, but it's something I want to work towards! I'll probably still have propane on-site for my wife's kitchen range.

It seems to me then that I'd be better off getting a dual-fuel Generac or Westinghouse setup for the house, and get a genset for my other stuff that can't use house power.

Is there a reference table somewhere that lists the names of the MEP units and their electrical output specs?

 

[MatthewWBailey]

Thanks for the responses so far everyone! @MatthewWBailey I appreciate your offer - I may send you a PM at some point

The responses here reminded me of another idea I had. I want my next home to have a solar array with battery storage, and condition the place with cold-climate heat pumps. The solar-battery part probably won't happen right away because those systems are ridiculously expensive, but it's something I want to work towards! I'll probably still have propane on-site for my wife's kitchen range.

It seems to me then that I'd be better off getting a dual-fuel Generac or Westinghouse setup for the house, and get a genset for my other stuff that can't use house power.

Is there a reference table somewhere that lists the names of the MEP units and their electrical output specs?

The guys on here would have the MEP lists. I actually do solar all over the county as a PE. 33states. Once you move, let me know and I'll connect you with a solar integrator that can help you. I'm in a remote area so have to build my own. I'm putting in 17kW ground mount with a modest battery setup and whole house inverter. The inverter can take a genset input and then manages the genset. Here's a pic of 2 of the racks. I have to drill in 5 more. I have space so ground mount is possible, just hard work installing.

You can taylor the $ expense around your usage and load management. Even a 3-4kw system can be effective depending on your layout and trees. Those should be <$15k roof mount. The current interest rates are not amenable to financing new projects but thats expected to change by '25, especially if you-know-who goes out to pasture.

 

[rtk]

I installed a Cummins 22KW natural gas genset 2 years ago and we love it . It runs my home 200 amp service and my 30x40 pole barn no problem at all , It runs about 15 minutes every other week and has given us no problems . Very quiet machine as well , You are not that far from me and you are welcome to come and check it out. The installer is from Rochester . It has provide power for several outages since install , once for about 12 hours never lost a beat , and it comes on fast . I would recommend the unit .

 

[Digger556]

My wife and I have talked about getting a back-up generator to provide single-phase power our house during a lengthy outage. Also, I want a generator to provide 208V 3-phase power for my ~1950 5-horsepower Federal Signal Model 5 air raid siren, and any other sirens that I might acquire (a Thunderbolt siren system will require 15 kW at the bare minimum). Who knows, maybe when I get my forever home I'll want to run some beefy electric motors for other stuff

I was originally considering a trailer-mounted MEP-805 for this duty, but some short research seems to indicate that the unit can't easily be wired for single-phase house power. Maybe I'm missing something?

Does anyone have any recommendations for what I should be looking for? Is there a civilian genset I should consider instead?

It sounds like you have two distinct situations that would not be easily covered by one generator. The two best 1P/3P generators are the MEP-802a (5kw) and the MEP-803a (10kw). Above the power output, most are 3 phase only. Some older units can be converted to single phase, but the loads are so light the engine will wet stack.

An average house uses about 30 kWh of power each day, which translates to 1.25 kW per hour, so on average you don't need that much generator.

A good power plan would use of combo of battery powered inverters charged by solar or the generator to provide basic power needs in a long term outage. Fridges, furnace, TV, phone chargers, etc. Save the generator for running larger, occasional use loads like washing/drying clothes, or the A/C during peak heat of the day. I aim to run the generators less than 4 hrs per day. If you want a good first hand account of a long tern outage, look here:
Super Storm Sandy multi-day outage.

 

[cdhendrix]

Those are 2 totally different applications. Your house is 240/120 1phase. As a PE in your state, I'd recommend a nat gas or propane duel fuel unit. ie Gas/propane. There are a few different makes out there that are totally enclosed. Generac and Westinghouse are good newer brands with warranties.
Key questions:
1. Do you have electric heat?
2. Do you have central AC or room units or heat pump?
3. Do you have gas kitchen range or electric?
4. Do you have well or city water?
5. What is your daily kwh usage(look at electric bill)

People always go overkill on kW which is wasteful. A typical house can run indefinitely on 5-7.5kw unless you have all electric on the first 4 above. Your "demand" is the defining parameter.

For long term house power, don't use a trailer mounted unit! Grounding and bonding can be major problems with those when interconnecting to a building, and you don't want to shock your spouse. If you spend more than $1, spend it safely and so that you can gain the added home value if you eventually sell. Get an automatic transfer switch so the operation is seemless.

Typical military gens are for field, temporary power, not for connecting to buildings. Use the MEPs for the sirens and esoteric 3 phase stuff by connecting that stuff directly to the trailer gens.

PM me if you need more specific info. I don't charge the fine folks on here unless I have to incur specific liability by issuing drawings or similar. Free professional advice is my way of giving back.

I have similar questions. To go through 1 through 4 I have a wood furnace central ac an electric stove and a well. I'm looking at a military generator specifically because of it being diesel powered. My reasoning for that is because I'm a farmer and heavy equipment operator and there's always diesel around. Where as I only have 2 25 lb propane tanks around.

 

[Light in the Dark]

I have similar questions. To go through 1 through 4 I have a wood furnace central ac an electric stove and a well. I'm looking at a military generator specifically because of it being diesel powered. My reasoning for that is because I'm a farmer and heavy equipment operator and there's always diesel around. Where as I only have 2 25 lb propane tanks around.

Whats the likelyhood that you will want to run all your burner elements, the oven, the well, and the AC all at once? How often do you lose power, and for what duration? What must you run in an outage, and what do you want to run?

Another option that works well for farmers are PTO generators.

 

[Light in the Dark]

Ideas on the range of PTO units, just like the range you can find in any other generator

Basic - https://www.northerntool.com/produc...atts-12-000-rated-watts-24-hp-required-165929 (brush head, unknown regulation, no gauges, 2 pole)

Intermediate - - https://www.powerequipmentdirect.com/Winco-W10PTOS/p12098.html (brushless head, capacitor regulated, only voltage gauge, 2 pole/3600rpm internal speed)

Heavier Duty - https://www.absolutegenerators.com/...-continuous-540-rpm-single-phase-120-240-volt (1800RPM, Auto Voltage Regulator, Brushless head, hertz gauge

 

[dougco1]

I installed a Cummins 22KW natural gas genset 2 years ago and we love it . It runs my home 200 amp service and my 30x40 pole barn no problem at all , It runs about 15 minutes every other week and has given us no problems . Very quiet machine as well , You are not that far from me and you are welcome to come and check it out. The installer is from Rochester . It has provide power for several outages since install , once for about 12 hours never lost a beat , and it comes on fast . I would recommend the unit .

Ditto here.
Very happy with my Cummins "Propane fueled " genset and it comes with a warranty.

 

[rtk]

Ditto here.
Very happy with my Cummins "Propane fueled " genset and it comes with a warranty.

For years I used portable GENSETS for backup power to my property , But you have to maintain them , get them out and set up , throw the transfer switch on the breaker panel from grid power to the genset and hope everything worked as it should . Plus most portable gensets are noisy and you had to keep fuel on hand , etc . Actually it was my wife who talked me into getting a whole house genset , best money we spent . I spent some time looking for a good setup and went with the cummins ,

 

[98G]

If you want to play with gensets, and to also have a source of power when the electricity goes out, get a MEP802. You'll probably get additional gensets as well. It's as bad of a disease as the green trucks...

If you want seamless power with no fiddling and no thinking about it, a propane generator is the answer.

 

[cdhendrix]

Whats the likelyhood that you will want to run all your burner elements, the oven, the well, and the AC all at once? How often do you lose power, and for what duration? What must you run in an outage, and what do you want to run?

Another option that works well for farmers are PTO generators.

Probably just 2 burners and the oven plus the well. Depending on the time of year maybe the ac. Usually once a year 1 to 5 days. Worst case a week to 10 days. I'd like to be able to at least be able to use the oven, well, hot water heater and the ac in the summer. I've thought about the pto generators in the past but I have never had a tractor around when I've had power outage. I have multiple farms and rarely have equipment at my house but have diesel at my house

 

[Light in the Dark]

Well you need to pull some amperage info off your hot water heater, and your AC... those will be the highest draw items you have. Unless you have a large well pump, so far my vote is an 802 for what you are looking to power.

 

[cdhendrix]

Well you need to pull some amperage info off your hot water heater, and your AC... those will be the highest draw items you have. Unless you have a large well pump, so far my vote is an 802 for what you are looking to power.

I can't remember what generator we used to use when I was in the army but I remember setting it up I was a 12N in a sapper company and we got saddled with a lot of the non sapper stuff. I'll look up the info on the well, water heater, and the ac. I know my well is about 400 ft deep

 

[MatthewWBailey]

I can't remember what generator we used to use when I was in the army but I remember setting it up I was a 12N in a sapper company and we got saddled with a lot of the non sapper stuff. I'll look up the info on the well, water heater, and the ac. I know my well is about 400 ft deep

So, there are diesel powered house getsets, but yes more expensive.

yes, get the HP of your well pump and get the starting VA or starting amperage from the chart orI can look it up. It's super easy to look it up.

@Light in the Dark is right, the fact is that loads typically don't coordinate so it's actually real hard to "turn everything on at once".

you really need to just have starting capacity for the automatic loads you have no control over: well, fridge, hot water heat. Those could overlap randomly. Basic engineering is to do some accounting of your loads. Add it up. It's very easy to put things on paper.

If you're hell bent on the MEP, as most on here are lol, (I get it, they're cost effective and fun), you'll have to worry about frequency stability and the frequency setpoint. That alone can cause modern appliances to shut down or worse. utility power is dead on 60hz by federal regulation, with a minor +/-. Portable Gens are not regulated as such and can fry your house, hence the dedicated gen products that have tight freq control AND a warranty to protect your appliances.

voltage regulation is another area of attention too.

More importantly, for MEPs you Will have to get into the wiring of the gen to open the connection between the winding and ground (Unless you use a 3 wire (3 pole) transfer switch that switches the neutral on 240/120), which is the more costly but feasible. It's not impossible but you've got to know what you're doing bc your putting your life at risk. Ground currents in a house are very misunderstood and are the cause of shocks that can be lethal. I'm not whistling Dixie here. however, there are many top operators on here that can do it no sweat. So there's that.

If cost is driving you to the MEP, just get the wiring diagram and get me and others on here involved to check your work. That way, there'll be 100% safety.

 

[Light in the Dark]

I'm not sure how familiar you are with the smaller MEPs MatthewWBailey, but here are some baseline characteristics for the liquid cooled 5/10s:



Past the torque that the diesel provides, the flywheels on these sets are about 50lbs of cast iron... they help to smooth out any inrush that would otherwise squelch a gaseous generator.

Also the units have the N-G bonding strap in place right where the lugs are, and its easy to unbond in the machine, for use with a grounded residential panel. For whatever its worth.

 

[MatthewWBailey]

I'm not sure how familiar you are with the smaller MEPs MatthewWBailey, but here are some baseline characteristics for the liquid cooled 5/10s:

View attachment 918172

Past the torque that the diesel provides, the flywheels on these sets are about 50lbs of cast iron... they help to smooth out any inrush that would otherwise squelch a gaseous generator.

Also the units have the N-G bonding strap in place right where the lugs are, and its easy to unbond in the machine, for use with a grounded residential panel. For whatever its worth.

Yes very nice indeed. The 3% freq is pushing the limit for some appliances. That's 1.8hz plus or minus which is greater than the utility tolerance. Some swamp coolers like BreezeAire for example, require a 0.5 hz tolerance bc they're using a speed control, and shut down if there's a higher frequency.
But, again, some Enginerring accounting, if there are no sensitive appliances in the house, then there's no problem with the MEP. It just needs attention and detail.

if the n-g strap can be removed, so the neutral is only connected to the house systems bond, then yes, that's the goal. But a dedicated ground EGC is then also needed back to the house panel so the gen frame doesn't become a shock point. Most gens are relying on that strap to ground the metal parts of the frame. It's so simple yet is so overlooked.