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Noisy power from typical backup generators

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Renate:

--- Quote from: IDEngineer on February 24, 2021, 06:49:50 pm ---...when dealing with line voltages that can be a dangerous game.
--- End quote ---
True, but in an emergency (and especially with 3 phase) you wouldn't jumper the phases?

IDEngineer:
Actually, no. I don't think I would. Just not sufficiently confident that nobody would "do something" totally innocent, unaware of a wildly illegal and inadvisable wiring change like that. If the whole structure appears to be powered it's too easy for someone to forget, be innocently uninformed, to presume all is well, and do something even more hazardous. Line voltage is unforgiving.

I'd probably just devolve to running a few key things using extension cords straight from the generator(s). But this is why I focus on having a single 2-phase generator adequate to power the entire structure. Then everything works properly, as expected, and there are no "special rules" depending upon what power source you're using at the moment.

YMMV, others might choose differently, standard disclaimers, etc.

EmptyHead:

--- Quote --- Incidentally, I did toy around with the idea of installing an electric start circuit to drive the PM alternator as a BLDC starter. I even got so far as to invest 16 quid in a 60v rated 300W electric scooter BLDC control unit with both Hall effect sensor and sensorless control options. I could get it to spin at about 480rpm using a 48v battery pack but only by removing the spark plug. Even blocking the spark plug hole with my finger whilst it was running was sufficient to stall it, proving that sensorless operation wasn't up to the task of handling such erratic mechanical loading.
--- End quote ---

I have a Honda EU2200i that I want to electric start so the lady can easily start with push of a button. Using the PM alternator as the starter motor is of particular interest. Any pointers you can share on this?
I would be interested in using a 12VDC lawn mower battery or Dewalt 20V max 9AH battery or Dewalt 60V 3AH battery(20v max 9ah)

First time post for me.

james_s:

--- Quote from: IDEngineer on February 24, 2021, 05:31:50 pm ---
--- Quote from: Renate on February 24, 2021, 12:19:42 pm ---Sure you can. Just jumper the phases in the main panel.
--- End quote ---
Wait, what? Surely you don't mean paralleling (jumpering) both phases so they act as a single phase?!? How would that work for 240VAC loads? At best they'd see a net 0VAC across their inputs.

--- End quote ---

It works just fine for 120V loads, I've done it for years, a friend of mine has done it for years. I don't have any 240V loads on the portion of my panel that is on the transfer breaker and neither does he but it wouldn't cause any problems, they'd just get 0V just as you'd expect. The little 2kW generators we have are not powerful enough to run the loads that require 240V anyway. They don't have to be, it would be silly for me to buy a gigantic generator that burns several times as much fuel just so I can run my clothes dryer or air compressor while the power is out. It's a backup generator, it's for emergency use. I fail to see how it is dangerous to feed both legs of the panel from the same wire. There's a physical interlock on the breakers so the generator breaker cannot be turned on while the utility main is on, and the bridge is in the socket on the end of the cord that goes from the generator to the house. I've been very happy with my setup and don't view it as a hack at all. A lot of people run extension cords all over their house to power lights and appliances in an emergency, *that* is a hack. I plug in my cord, fire up the little Honda, and then go in side and shut off the main, slide the interlock up and turn on the generator breaker and all of my lights and 120V loads are powered. I have an alarm that detects when utility power has returned so I can go shut down the generator and switch it back over so I'm not that guy who leaves the generator running for an hour after the power has come back.

Look at the fuel consumption, a 3kW generator uses quite a lot more fuel delivering say 500W than a 2kW generator does supplying the same load. A 7kW generator will use a LOT more fuel powering that same load, not to mention it will be much heavier and take up a lot more space. If you need the power then buy a generator that can meet your needs, but for those who can get by with less the little 2kW suitcase units are fantastic, mine lives in a closet in the utility room when not in use and when I need it I can carry it in one hand. At light load it will putter along for around 12 hours on a single gallon of gas. It's small enough that I can set it in my car and use it for camping or running power tools in a remote location. My neighbor's gigantic 8kW generator slurps down more like 6 gallons of fuel in that same time, makes so much noise that I can barely tell mine is running standing a few feet away from it over the din of his across the street and his is so bulky and heavy it has to be rolled around on wheels. No thanks.

Renate:
Ah, camping, back to nature, peace and quiet.
For some Americans that apparently has no appeal.
No, this photo is not from a rock concert only a little camping site.

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