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Features to look for in stand alone generator
Yikes, I'm out of time today, but I will participate in this one. I've got a Honda 6500 that's 5000 or 5500W continuous. It does the job described, although it's not too happy about the furnace and water pump starting while the fridge is on. High electric motor starting loads are hard on generators and should be minimized. Using the generator for emergency backup, I juggle loads around and try to keep only one motor load active at a time.
The 6500 even does a decent job with the stove as long as only a bit of lighting is also on. My only complaint is that the cold weather starting isn't great and I usually use a whiff of ether during the winter.
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Features to look for in stand alone generator
In pro audio equipment I’ve found that it almost takes an engineer to sort out the specs. It depends where on the power curve noise and distortion specs are taken, and specs tend not to be comparable.
I'd be more concerned by the possibility of voltage surges, sags, spikes and transients than wave shapes and harmonics. Running a signal through a transformer and power supply tends to shape and clean up many signals. However, if high AC quality is required, there is a variety of specialty power conditioning equipment used by sound companies that have to work with bad AC.
I think that a sine wave is the natural form of a signal produced by an inductor rotated in a magnetic field (basically a generator). If a generator produces a different waveform, then I'd suspect an engineering trick designed to justify a big power spec. High-end equipment don’t usually rely on tricks, because there are always costs to these things. Specs may be pretty illusionary. However, I'd guess that a generator's duty cycle is a pretty good proxy measure for quality. I'd look at the difference between peak and continuous rating and also how long peak levels can be maintained. Something close to a 100% duty cycle and able to sustain peak loads for longer periods probably produces high quality AC too.
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Features to look for in stand alone generator
Yes, true about harmonics and waveforms. The combination of transformers and filter networks in some power supplies do a decent job of rejecting harmonics. Some pro audio power supplies are designed to clean up AC. Never the less, I always used moderately expensive surge protectors that also contained noise filters on all my pro sound equipment. However, I had more sound problems due to poor AC grounding than to dirty AC.
I've heard discussions about armature construction in high-end generators. I believe these engines tend run at half the RPM of standard generators. I've also heard that these high-end features including true sine wave may not be too important for an emergency power backup application. Even equipment with low expected service life ratings may last indefinitely unless utilities become even more unreliable. I don't know how comparable service lift ratings are but they may be good to check.
Similarly, fuel efficiency may not be all that important, but noise was a very important consideration to my wife. That's probably why we ended up with Honda, or at least that's how they're advertised. We may not need the long life but it is quieter. Wife still grosses about the noise even though the generator sits in a shed over 50' from the house. I can comment about generator hook ups to utility equipment if interested.
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Features to look for in stand alone generator
Steve: The lower RPM generators probably are quieter but also have much longer service lives. Maybe important for somebody like John who may get into the competitive power buz (That's just now cooking up here in Ontario). Yep, I thought I'd be getting a PTO generator when I first got the tractor. I made all sorts of brave pronouncements about not having a flock of small engine sitting around. Of course, that's exactly what I ended up with. The tractor does what it does well and so do the small engine toys. I understand big PTO backup generators for dairy farmers--bunch of grumpy cows and bad milk if the power goes down for long, and it takes a bunch to run a dairy operation. For emergency backup, I don't need everything on in the house at the same time, and I don't want to put a generator on the 3ph in the dead of stormy nights.
John: My hookup is a sub-panel that runs as a 60-amp branch circuit on the service panel. It has it's own 3-point main breakers for utility and the generator supply and mechanical linkage that prevents both mains from being on at the same time (3-point here is two hots and the neutral rather than tractors). I got a 60-amp panel with 24 branch circuit slots even though the generator puts out 22.5A/220V peak. I wired most of the original house on the backup panel even though I can't run it all. However, I can power most everything in the house by juggling branch circuits around.
My feed runs just over 100' with a 30' underground section. The underground runs through conduit so I can pull the wire by just digging at each end. I used 10-gauge (30A) line, which meets codes, but I also can't just hook up a larger generator. There probably is appreciable voltage drop over 100' and it may have been better to start with 8-gauge wire. I also could have used 1" rather than 3/4" conduit for the up sections.
I don't think my arrangement would work for you. I can't imagine a utility allowing surplus power to be fed to a grid by backfeeding it through service panels--could be wrong though. I expect they'll want transfer switches. The trouble with transfer switches is that they have to be rated at least as large as the utility service. A 200A transfer switch is very expensive, but I guess it could end up as a business write off.
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Features to look for in stand alone generator
I probably should point out my basic ignorance of small buz, or green power suppliers as they're called here before somebody else does. I might learn something. My impression is that this is low voltage generation that gets on to the grid by back feeding service transformers at higher voltages than supplied by the utility. Now that I think of it, I'd be surprised unless something more sophisticated than a meter is required.
This could be an interesting thing to do. With the way electrical rates are exploding around here, I can easily see that it might be cheaper to generate your own power by generator during 'gas wars' than to buy it from the utility. And of course, once it's in place solar, wind etc. is a whole lot cheaper and a lot greener than a gas generator. So, if it's cheaper for an individual, why not sell surplus to the utility?
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Features to look for in stand alone generator
Gee! Seems like I got it basically right. The concept of using the utility as a back up battery is a very appealing idea. I talked with a solar power consultant several years ago. He said that considering the costs of the equipment and electrical rates, people who already had utility power on the property would never get the investment back. He said his main business was for properties that would have to put in lengthy runs of private over-head lines to get utility power. But that was several years ago, the costs of solar panels etc. and electrical rates have changed radically since then. Sounds like maybe it’s time to revisit the idea.
I did sort of anticipate the need to sync the phases, and maybe some sort of voltage feedback to control current delivered to the utility. I can think of several ways to coordinate an inverter. More tricky with an engine, but I guess if gas became cheap enough, a generator could be used to charge batteries at a profit. Batteries would clean up dirty 12V DC nicely.
In terms of looking at generators; I recall that my township has a Kubota generator that I think is a 30A/220V peak generator. Don't know much about them except, like the tractor, it's orange and looks good. Might be something to check, considering the brand name.
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Features to look for in stand alone generator
Guess I've got several things to say. The first one could save somebody a bunch of money. Easements can be buggers to deal with. We almost had the power disconnected at our camp while we did a demolition and eventually put in a new service. A utility company site planner saved us. If we had disconnected, it would have cancelled an existing easement and would have required a new survey ($5,000CAN minimum) to get another. The order had to request a 'temporary disconnect pending service upgrade' to preserve the easement.
The second thing is that generator panels or transfer switches are very good things. Before we installed one, I used a 100A panel and a flock of receptacles on a piece of plywood that I had from my old sound buz. I added a stove receptacle and put twist-lock plugs in the well pump and furnace lines so I could run extension cords from the panel. The arrangement does 100% isolate the generator and utility equipment, but an inspector after we installed the generator panel didn't like the twist-locks. No pain though, the generator panel is much better. The old sound buz panel remains useful at building sites without power. The panel provides a number of 15A/120V outlets, some of which are GFI protected. It also provides a number of special receptacles that 220V equipment may use but may not be on a generator.
The last thing is that I guess a 1000' of service line would be overhead. We had one pole with a pole service on it put in. A pole contractor came with digging truck towing the pole trailer. He'd already put the panel, conduit, and even the ground plate already on the pole. He had the pole planted in under an hour. Those digging trucks are sure something--make tractor hydraulics look like it's barely there.
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Features to look for in stand alone generator
That sounds like a good result. Even though I think of costs in $CAN, the cost seems much more reasonable than I would have thought. Texas is big. I hear it takes three months to get a phone call across the state.
Yes, underground is good. The utility 14KV line across the highway us has a bunch of splices in it from downed trees. We were here for one of them. It makes a real good fire in the bush, and it took the utility over two hours just to cut off the power. In the meantime, it was just a couple guys from the township throwing shovels of sand whenever the flames flared up. Real fortunate it was raining at the time.
I'm not sure, but it sounds like the buried line is 14KV line to a 220V transformer. It's good if the utility allows private work to run distribution lines. I'm pretty sure our utility would require that they do all work themselves, and their rates are pricey even compared to contractors.
I'm a little surprised you pulled cable through 800' of conduit. Usually I hear about 'pull-points' or what ever they're called every 200' or 300'. I suppose we'd be required to use them here, and such things do run up the costs. But as I mentioned, we'd start out with $5,000CAN min just for an easement survey. I wonder why government cutbacks only seem to get rid of the things I want, and every other government thing just keeps going up. Well, maybe it's just here or maybe just me. Anyway, glad you got the power and at what seems a bargain to me.
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Features to look for in stand alone generator
Sounds like a contractor is going to do the work, so problems like length of the run and voltage drop would be their buz. If the run is under-ground, I don't know at what distances pull boxes in a run start being used but something like that may be an issue with runs around 300'. It can be a difficult to pull 200A triplex through 300' of conduit--especially if there are sweeps and even more especially it's copper line. However, that issue does sound like it's the contractor's problem.
Aluminum DB line sure does pull easier and it's a lot cheaper, so maybe that's your issue as well. The 80' of aluminum 200A DB line for our house under-ground service was pricey. It was supplied by the utility and cost more than the 300' or so of overhead line from the transformer across the highway.
I supplied 30' of DB line from a 200A pole service I put in to a construction trailer at our camp. I ran the trailer feed as a 100A branch circuit. I used 100A copper DB line and the price really took my breath away. The electrical supplier says 'I'll have to order the copper in but I have aluminum in stock and it's about half the price.' Well copper is what I'm used to working with so I bit the bullet and bought copper. I think I might have to mortgage the tractor if I was looking at putting in 300' of 200A copper underground.
My impression is that a 1A trickle charger can be left connected indefinitely to a sizable battery. Maybe I'm wrong.
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