Upcoming project - A standby home generator

Harvey said:
I've got an extra 1930 4 cylinder Ford flathead engine that puts out 40hp (on a good day). Could it be used to run a generator? That would make a neat project!
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Glad you liked my post, Harvey. That would be a neat project, but one of the problems when generating your own power is arriving at the correct frequency. You could purchase a belt driven governor to regulate the engine speed to provide 60 Hz. Most generators are designed to be driven at 1800 RPM for 60 Hz. The frequency would not need to be dead on, but any clocks that you have running would reflect and discrepancy. Furnace blower motors, refrigeration compressors, etc, light bulbs, do not require accurate frequency generation; you could be off 10% either way and be fine for the most part. Anyway, that engine running constantly at that speed, and at high load might prove to be too much for that engine and it's cooling system.

twstoerzinger said:
One of the big concerns will be the transfer switch. The power companies are usually very insistent on having a certain style / design / rating of transfer switch. They don't want you to electrocute one of their linemen working on what was believed to be a de-energized line.
You might check on your power company's website for information on transfer switch requirements for home generators. Where I live, the power company has a pretty good treatise on home generators, transfer switches, and the installation / approval procedure.
Terry S.
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The transfer switch out at the farm cuts the entire place on and off of the grid. It is basically a big 3 pole knife switch up on the pole, manually operated by a handle at the bottom of the pole. It ensures that the whole farm is on either grid power or on the tractor/generator. There was no possibility of backfeeding the grid. If the power failed, you would hook the generator up to the tractor, back up to the pole and plug in the generator cord. Fire up the tractor and generator, set the RPM, then cut the switch over from the grid to the genny. GREAT spark show at night! If you attempted to switch to the generator, then engage the PTO and bring it up to speed, you would typically shear the bolts on the PTO shaft! Switching back to the grid was just the opposite, except that you shut the generator down before switching back to the grid. The knife switch was fine with making contact, but had issues breaking contact under load.

At home, I have my furnace shutoff switch replaced with a receptacle. The furnace itself is on a very short cord that plugs into that receptacle. To go on generator power, I have to unplug from the receptacle and run a cord out to the generator, isolating my furnace from the grid. It takes a little bit of work to stretch out the cords I need, but no transfer switch is needed, and yet everything is safe. The generator is set up in the garage, with a couple of windows left open for ventilation. Generator and cords all stay high and dry. Since I have more time than money, a little bit of easy work is like money in the bank. The worst part is that I always have to be sure that I have ten gallons of gas on hand for the generator, which is enough to keep things going for several days.
 
All electricity is dangerous if it's not hooked up right. The neutral in my panel runs to ground, it would run to ground before a lineman gets zapped.
 
If you're self-generating power, you need a "Kill A Watt" meter like this: http://www.ebay.com/itm/P3-KILL-A-W...603?pt=LH_DefaultDomain_0&hash=item3a752ec163

Just plug it in and it will tell you the frequency. It's how I adjusted my generator by tuning the throttle control until it read 60Hz then, lock in the governor. On my generator (which is quite stout) frequency stays between 59.8 and 60.2 Hz. That's very good and won't cause any fancy electronic devices or computers to kick-out. Virtually all power supplies in modern day consumer electronic goods will reject (shut-off) input if frequency goes beyond 2% up or down.

Also, modern day clocks have their own internal oscillators so they are immune to frequency variation but, like Terriworm said, any old analog clocks will vary time with irregular power.

Finally, those ST-type generators in the link below are pretty good. Not the greatest waveform in the world but good enough to do the job. They are self excited and if you replace that circuit (as I did) with an external circuit, the generators produce a very nice, fairly clean sinusoidal waveform.

Ray
 
Oh, and if you really want a diesel unit, save yourself a lot of trouble and just get this: http://www.harborfreight.com/20-kw-generator-192.html

All the headaches already worked-out. Units like this need to be written into your Will to give to your grandkids. Under half load, they consume about 5lb fuel/hour (one gallon per hour, roughly) but, under typical loads of 3-5kW you go three hours on a gallon of diesel.

Sometimes these units are available at auction from the armed services. Millions of units like these were used in the last desert wars. They ran the daylights out of them (24x7) and they need to be rebuilt but once that is done, they're good for another lifetime.



EDIT: More realistically, get this: http://www.harborfreight.com/8750-peak7000-running-watts-13-hp-420cc-gas-generator-68530.html

These are actually decent units. I know two people who have them. They don't have the twin cylinder engine but, all things considered, they're OK. I'm toying with the idea of getting rid of my Kubota setup and just getting one of these. I need the storage space taken-up by the behemoth unit I have.



Ray
 
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I just happened to notice that the ST generator place sells AVRs which, is very convenient. Those are not traditional AVRs though... You use two small leads from the output of the generator and connect that to the input of the AVR. The AVR also has outputs that replace the self-exciter circuit in the generator. The AVR then controls the primary winding field current with a nic clean signal to keep the secondary output windings at a constant voltage. The weakness of the ST-type generators is the quality of the primary field current produced by the self exciter. It's noisy as heck and it transfers/amplifies like heck in the secondary output. Anyhow, this is the same kind of circuit I have in mine but, these are readily available now and I had to scavenge one off an old industrial unit back when I made mine. I highly recommend this type of circuit. If you go this route, you just remove that control box they have and put the AVR inside.

Aside from that, those ST-type generators are built like tanks and have a very high service rating. They will produce rated power effortlessly for days on-end. The bearings need grease once a year but the first time you do it, you'll install zerks to make it easier next time.

EDIT: And here's a really good example of a good engine for driving 25kW continuous: http://www.ebay.com/itm/Kubota-V220...218?pt=LH_DefaultDomain_0&hash=item35bcdb3cb2 For higher altitudes these can outfitted with a blower. Some models have a built-in governor and there is a governor kit available.


Ray
 
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And finally, if you want to go retro, get a Lister engine like this. They only put out 6 horsepower (about 4kW) but, can do it and will run continuously for literally, decades. They run on anything from diesel, diesel-oil, bio-diesel... They have to be started with a hand crank -which can rip your arm off and/or kill you if you don't know what you're doing. They run very quietly and only at 600 RPM -very melodic and relaxing sound. Water cooled and you can scavenge the heat into your garage if so inclined.

http://www.ebay.com/itm/8-1-Lister-...505?pt=LH_DefaultDomain_0&hash=item3a80dd3f69

I had a collection of these from 6 up to 20 horsepower.

(oh, they weigh between 1/2 and 2 tons).

Ray
 
Please read and understand twstoerzinger post.

One of our Dayton Fire Fighters is a Lineman Supervisor.
This is a huge concern of his.

There are ways to build an end-round as suggested in this thread.
I've done so.
However, there is no way I would suggest that my wife follow the procedure to power-up or power-down the system run of my welder/generator.
She would hurt herself and/or the linesman as I didn't invest in the safety technology.


Daryl
MN


twstoerzinger said:
One of the big concerns will be the transfer switch. The power companies are usually very insistent on having a certain style / design / rating of transfer switch. They don't want you to electrocute one of their linemen working on what was believed to be a de-energized line.
You might check on your power company's website for information on transfer switch requirements for home generators. Where I live, the power company has a pretty good treatise on home generators, transfer switches, and the installation / approval procedure.
Terry S.
Click to expand...
 
A manual transfer switch is not that much and should be used.

On the fuel issue, if using gasoline, make sure to find gasoline that has not been laced with alcohol. Premium tends to have no alcohol but you have to check. http://pure-gas.org/ The poison that the station operators/refiners are required to put in the fuel will seperate and there lies the problem. I run premium in my Honda EU3000is, the motorcycle and snowblower. The car requires premium so this in not a problem for me. Everything uses the same stuff.

What happens is the alcohol in the fuel will stratify in a short period of time, as short as 2 months has been reported, with the water that has been not picked up by the alcohol in the bottom, a layer of saturated alcohol/water that has seperated from the fuel next and not so good gasoline on top. That gasoline is no longer 87 as the alcohol is used to bring cheap low 80s octane gasoline up to 87. On carburated equipment this stuff will run poorly or not at all depending on the fuel feed pipe location in relation to the height of the tank. Another thing the gasoline is thin to begin with and the engine will run lean unless you can either rejet or some how increase fuel flow by about half the amount of alcohol added. 10% alcohol increase fuel by +5% to return to normal air/fuel mixture. This does not apply to injected engines as usually they have an O2 sensor to control the mixture. YMMV!
Pierre
 
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