Running Generators in Parallel?

[RNeumann]

Second this given OP’s budget.

OP needs to think in terms of powering circuits (kitchen plug, bathroom light, heater fan motor etc) instead of the whole house. With that approach the two gens won’t be an issue.

 

[LouNY]

Every one trying to save the OP money should remember he is using the second house as a B&B, someone paying to stay is not going to want a noisy generator sitting next to them with cords running around to power a few circuits.
As I recall his main comes from the same drop for both houses, if so quite playing around get a DPDT transfer switch rated for full capacity and then a PTO generator of 15-30 KW capacity,
one switch, one generator, power available to both houses and he can then prioritize which beakers get turned off and when.
Yes a large transfer switch is expensive but it's the easiest to use and easily modified for different generators.

 

[wagne223]

Let’s try this another way......

A 120v gen won’t simply plug into your house (through transfer switch or otherwise) and run all your 120v appliances. The panel has 1/2 the circuits on one phase and the other 1/2 on the other phase.
OP doesn’t have the knowledge (based on the question (which is fine)) of electrical to know about phases, htz etc. So suggesting a 120v gen will work on a tight budget doesn’t paint a very accurate picture. A lot of the money would be eaten up adding or modifying the existing electrical panels at both houses.
If the OP sticks with 240v split phase gens (standard in the USA), he will get what he wants to back feed the house and run his welder. The brand, size etc will depend on the budget and brand recognition.

*as a note- with some modifications and illegal wiring their is a way to energize all 120v circuits in a panel with a single 120v gen. The juice isn’t worth the squeeze in most cases and risk of property loss or injury is real.

100% agree!

These threads always make me uneasy.

There is a big difference between a person that has extensive knowledge about electricity, structure wiring , and generators and a handy person that wants to simply start a generator and connect a plug to power their home.

No offense to anyone. We all have different knowledge and skills.

Can two non inverter generators be pallelled, yes, however it is a process that if done incorrectly results in catastrophic failure.

Can 2 homes be powered by 2 generators and tied together to spread the load, yes, however the gens must be synced, see above.

Errors with this subject result in equipment damage, appliance damage, house fire, and worse, injury or death.

The best solution in this case is a separate generator for each house. The proper way to connect a generator is through a transfer switch ( manual or automatic) or a generator circuit wired into the electrical panel with a lockout.

The lockout option is usually less expensive if a lockout kit is available for your panel.

Stay safe.

 

[Industrial Toys]

That 12.5 KW Isuzu Generator Ralph mentioned is a sweet running machine. It's a current project of mine.



I bought a 200 amp ASCO Switch (I figure one of the best) off E-bay CHEAP. You don't always need to spend lots of money to get quality and substance!

 

[Tractorable]

Thanks for the responses.

Money is part of the issue but not the entire issue. I'm willing to spend some cash for a good solution. However, you may have seen in my profile that I currently have a 1952 Ford 8N and my main focus right now is to save up and replace it with a new Kubota or Yanmar. I'll use the tractor a lot more than I'll use the generator so I need to put my money where it matters most.

The lady down the street had a dedicated standby generator installed and it cost her $15,000. I'm not willing to spend that kind of money on a generator because I could almost get a new Kubota L2501 for that. I'll probably go for dual 7500W gens, one for each house, connected to transfer switches. I'll have the electrician wire 220V in the garage for a compressor and welder while he's installing the transfer switches.

Here's a link to the AirBnB. There are some pics of the old 8N and the layout of the property is in the last pic. Firefly Cottage - Houses for Rent in Marshall, Virginia, United States

 

[Sawyer Rob]

A PTO unit might be OK, but you may have some problem holding the cycles in an acceptable range.

WHY? I've never had that problem with mine, no matter what the load was...

SR

 

[RNeumann]

WHY? I've never had that problem with mine, no matter what the load was...

SR

RPMs change the voltage and htz. With inconsistent loads and an engine that doesn’t hold rpm no matter the load it can be an issue.
Most generators automatically change RPM and or hold RPM depending on load. Most tractors don’t do this.
A PTO gen would be a good fit for something that was high draw, but consistent, like a big water pump for irrigation.
OP- you are on the right track for your situation!

 

[Sawyer Rob]

RPMs change the voltage and htz. With inconsistent loads and an engine that doesn稚 hold rpm no matter the load it can be an issue.
Most generators automatically change RPM and or hold RPM depending on load. Most tractors don稚 do this.
A PTO gen would be a good fit for something that was high draw, but consistent, like a big water pump for irrigation.
OP- you are on the right track for your situation!

All tractors have governors, just like the engines on any other generator...

More load, the tractor governor adds fuel to keep the rpms where they should be, so a pto gen set is NO problem at all...

SR

 

[RalphVa]

That 12.5 KW Isuzu Generator Ralph mentioned is a sweet running machine. It's a current project of mine.

View attachment 551841

I bought a 200 amp ASCO Switch (I figure one of the best) off E-bay CHEAP. You don't always need to spend lots of money to get quality and substance!

Yeah, bought from Central Maine Diesel. The enclosure I bought from them has tended to rust around the edges of cutouts, etc. I've painted on Rust Reformer and seemed to have stopped this. Also give the paint a wax job a couple times/year.

Disappointed in the seemingly poor quality of the radiator hoses. NOT like the really high quality (rad and heater) hoses (never replaced) on our 1983 240D Benz that we had through age 26. Think I'll have to order new hoses from Central Maine when I change out the coolant at around age 10. Thinking it would be very difficult to match them up with local hoses.

Ralph

 

[Industrial Toys]

Not an expert, but once a conventional generator is locked in to another, they will follow each other. But I think, they must be close in capacity. How do you think they keep Niagara falls in sync with some nuclear station? Not, by closely trying to control each generator speed down to a fraction of a cycle.

But back to home stuff, most generators have an electronic voltage regulator. So no, RPMs don't effect voltage on the output.

Ralph. At least you have hoses. That Onan/Isuzu had some remotely mounted rad. Changing it over to conventional rad, electric fan and appropriate hoses has been way more work, effort and money than it might be worth. I don't need another generator, but if I did, the Ebay Military surplus route would be a better bet. For the quality, I bet that 15,000 dollar installation is probably a huge ripoff if it's consumer type crap!

 

[LouNY]

^^^ Well put! :thumbsup:




You really won't be that far off from a decent quality dedicated unit.
A PTO unit might be OK, but you may have some problem holding the cycles in an acceptable range.

As others have mentioned tractors have governors, I've had several tractor run PTO generators and they all held reasonable frequency, my old 574 would hold within a half a hertz from a minimal load to too a heavy one on my 25kw generator. The last time I looked a 25 KW pto unit was well under $3000. I realize the OP's 8N is only 20 HP or 10 KW of generating capacity, but it can spin a larger generator for that 10K load.

 

[BoylermanCT]

Thanks for the responses.

Money is part of the issue but not the entire issue. I'm willing to spend some cash for a good solution. However, you may have seen in my profile that I currently have a 1952 Ford 8N and my main focus right now is to save up and replace it with a new Kubota or Yanmar. I'll use the tractor a lot more than I'll use the generator so I need to put my money where it matters most.

The lady down the street had a dedicated standby generator installed and it cost her $15,000. I'm not willing to spend that kind of money on a generator because I could almost get a new Kubota L2501 for that. I'll probably go for dual 7500W gens, one for each house, connected to transfer switches. I'll have the electrician wire 220V in the garage for a compressor and welder while he's installing the transfer switches.

Here's a link to the AirBnB. There are some pics of the old 8N and the layout of the property is in the last pic. Firefly Cottage - Houses for Rent in Marshall, Virginia, United States

Beautiful cottage! I have it bookmarked in case my wife and I need a vacation soon!

My vote is to buy two inverter generators like the Harbor Freight ones for $750 a piece. Inverter generators are much quieter which is what you want on a B&B. Get a transfer switch in each house and 240V plug on the outside of the house with a 25' 240V cable.

 

[LittleBill21]

Beautiful cottage! I have it bookmarked in case my wife and I need a vacation soon!

My vote is to buy two inverter generators like the Harbor Freight ones for $750 a piece. Inverter generators are much quieter which is what you want on a B&B. Get a transfer switch in each house and 240V plug on the outside of the house with a 25' 240V cable.

still only going to get him 120v, those generators don't do 240, the only one i am aware of that does is the honda 7000 series

 

[buickanddeere]

Place this just after the utility meter . TWB212DR Panel/Link - Reliance Controls Corporation

 

[buickanddeere]

Place this just after the utility meter . TWB212DR Panel/Link - Reliance Controls Corporation

 

[wagne223]

still only going to get him 120v, those generators don't do 240, the only one i am aware of that does is the honda 7000 series

100% Correct.

The EU7000 is on my list for home backup power. I want to replace the Briggs construction generator I'm using now.

 

[wagne223]

Not an expert, but once a conventional generator is locked in to another, they will follow each other. But I think, they must be close in capacity. How do you think they keep Niagara falls in sync with some nuclear station? Not, by closely trying to control each generator speed down to a fraction of a cycle.

But back to home stuff, most generators have an electronic voltage regulator. So no, RPMs don't effect voltage on the output.

Ralph. At least you have hoses. That Onan/Isuzu had some remotely mounted rad. Changing it over to conventional rad, electric fan and appropriate hoses has been way more work, effort and money than it might be worth. I don't need another generator, but if I did, the Ebay Military surplus route would be a better bet. For the quality, I bet that 15,000 dollar installation is probably a huge ripoff if it's consumer type crap!

Yes, with conventional single phase generators, once they are in phase, they are magnetically locked. If one shuts down, say for low oil, the other will drive it.
This is where the risk comes in.

As far as grid generators, same principle, however they are easier to synchronize because they are 3 phase and the prime movers have precise RPM control.

 

[Tractorable]

100% Correct.

The EU7000 is on my list for home backup power. I want to replace the Briggs construction generator I'm using now.

Those Honda EU7000's sure look nice, but at $4000 a pop, and having to buy two = ouch!

 

[bigdeano]

Two generators in parallel would have to be very closely matched in voltage, not just frequency. Also they could probably get into an oscillation mode where one throttle opens which closes the throttle on the other one, and then back and forth. It would be interesting to try if a person had 2 identical generators.

 

[LouNY]

I'm having to stretch my memory some the last time I had to sync generators was going on 30- years ago.
These systems had backfeed cutout relays and quite a few protective devices these were steam and gas turbines with diesel load sharing,
startup and backup.
On a startup with the generating system on line and loaded we would bring the next unit up to speed and once ready to use with the voltages
equal and the rotating speed just a touch higher and watching the sync scope just slightly turning faster when they came into sync you'd throw the
breaker to close then throttle up that unit to carry the desired load.
The difficulty was maintaining a load on all the desired running units, when you had a lot of generating capacity on line and something happened to your
load, auto throttles and synconizers had a heck of a job backing down and quite often one or more units would trip on back feeds and disconnect and then the
balancing act would start again.