An Alternative Home Power Source.

[Daren Todd]

Sams club got in a pallet of champion dual fuel 4400 watt generators. Were selling them for $372.

Ended up picking one up yesterday for a just in case.

We've never really required much. At the old house we got by with a 3000 watt Chinese no name model. House had a fire place insert so the generator ran the blower for the insert to heat the house, and a few lights, the TV, and microwave. We gave the Chinese model to our son when we sold the house.

New place, we would just need it to run a few lights, and a couple space heaters. We got the old microwave out in the garage. So we can dig that out if we need it since the new house has a built in microwave over the stove.

I can always fire up the grill to cook on

 

[GreensvilleJay]

I've got a 8KW unit, 16Hp tec engine sitting here(gummed up carb)..can't be bothered to reassemble.
it also is a portable welder..needs cables.
my current backup power is a 1200W old skool UPS, I run off car batteries( or forklift..).Purrfect sinewave,solid 10amps..will run the NECESSARY stuff

 

[Old_Paint]

Always wondered how home solar/wind systems 'sync' onto the 'grid' to get the phasing right, espcially if grid goes down..you supply power...grid comes up...

The grid-tie systems have sensors ([PT's] Potential Transformers) on the utility input and inverter output which will measure voltage, frequency, and phase angle, and since they're electronic, will very quickly adjust everything to match the utility before tying back in.

Off-grid systems don't do this at all, and have to be operated in open transition modes. In fact, they MUST stay separate from utility connection. Open transition means the connected source is disconnected before the other source is connected. That prevent's back-feed and out of phase switching which will likely damage the electronics. Probably not going to hurt the utility, and at worst, might blow a fuse. Likewise, small generators rarely have any means to parallel them (grid tie) with the utility. I think the smallest I've ever seen with paralleling capability was about 600KW, with a 1200 HP V-16 Cat driving it. The largest one with a reciprocating engine I've ever worked on was a 2MW diesel powered Stewart-Stevenson at the local VA hospital. I've done systems for controlling and paralleling 80MW gas turbine systems in paper mills, and countless others in the 40MW-60MW running on steam.

Normally, for paralleling, the generator is run at about 0.25% faster frequency than the utility, the voltage raised about 10% higher, so that when the breaker or transfer switch closes, the generator will continue to try to output power. Until it actually connects to the utility, it normally runs in a speed (frequency) regulated mode. When the isolation device closes, a contact from that normally tells the controller to switch to load control. This keeps the throttle from opening wide open and burning up the generator. But frequency control and voltage control are hard to put on small generators. Very few have even any excitation control to vary the voltage output. Most just have a mechanical governor and get somewhere near 60 Hz. Close is good enough for most residential applications. If you get into hospital applications, however, they must be much better control systems because a lot of equipment in a hospital is very senstitive to frequency and switching transients.

 

[Magicman]

Most just have a mechanical governor and get somewhere near 60 Hz. Close is good enough for most residential applications.

Exactly. When I first cranked up my generator it was supplying the approximate correct voltage but at 52Hz. The Champion Factory Technician directed me to the throttle/governor screw which I adjusted to reach 61Hz no load. He told me to watch and tweak it under a normal load.

 

[Old_Paint]

Exactly. When I first cranked up my generator it was supplying the approximate correct voltage but at 52Hz. The Champion Factory Technician directed me to the throttle/governor screw which I adjusted to reach 61Hz no load. He told me to watch and tweak it under a normal load.

Yep. Don't set it for worst case (AC starting with the oven and hot water heater on). Set it for something close to 60Hz with normal loads running.