Lessons from Sandy

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A thousand watts is 85 amps at 12 volts. Most automotive alternators will fry if you try to run them at that level, though some heavy duty truck alternators will handle 1000 watts continuous. Your typical car alternator will put out 50 amps at 14 volts at 4000 RPM, which is above engine idle. You can retrofit a heavy duty 150+ amp alternator with a small pulley to make it spin faster, but modern cars with their tight engine well and serpentine belts make that a PITA. It would be easier to just get a 3 hp lawnmower motor, mount a heavy duty alternator and a battery, which would give you 1000 watts easily while running the engine at moderate speed.
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Larry wrote:

There are several plans on the web, with parts lists, of lawnmowers repurposed into generators.
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On 01/11/12 20:13, HeyBub wrote:

Hint, just make sure it is a working lawn mowers engine before you start.
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terryc wrote:

I have an electric lawnmower...
Never mind.
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On 02/11/12 00:28, HeyBub wrote:

lol.
umm, have you considered a hand generator for it?
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On Thu, 01 Nov 2012 21:13:54 +1100, terryc

better with the cast iron flywheel instead of the aluminum flywheel on most rotary lawn mowers. Using a rotary mower engine you will need a big heavy pulley to act as a flywheel or it will be VERY HARD to start.
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On Thu, 01 Nov 2012 17:05:45 -0400, snipped-for-privacy@snyder.on.ca wrote:

That is true. There is virtually no flywheel on a lawn mower engine, they depend on the blade to be the flywheel. I couldn't even keep a regular deck style mower running without the blade.
The engine on my redneck 12v generator is from a worn out pressure washer. The Honda engine will run for years more.
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Actually..you are better off snagging the complete front end from a Honda, or other small car, pulling the engine, mounting it on a stand and adding a set of pulleys and a gen head.
http://www.harborfreight.com/engines-generators/generator-accessories/10000-watts-max-7200-watts-rated-belt-driven-generator-head-45416.html
As an example. A regular automotive small engine will simply idle and drive that gen head quite nicely. Anything bigger than 20 hp will be more than enough. Hell..a motorcycle engine from a 450cc or bigger should drive it nicely
Gunner
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On 11/3/2012 4:43 AM, Gunner wrote:

http://www.harborfreight.com/engines-generators/generator-accessories/10000-watts-max-7200-watts-rated-belt-driven-generator-head-45416.html
If you can set up the pulleys correctly to get a small liquid cooled engine to run at 1800rpm and spin the generator at 3600rpm, you will wind up with a very quiet, reliable genset. A heavy flywheel could help but I suspect the mass of the armature would be enough to keep power output steady. I installed a lot of generators in homes and businesses back in the 90's after a major storm upset the power grid in my area and my favorite gensets and the ones that had the fewest problems were those that had liquid cooled engines running at 1800rpm. The 3600rpm gensets with air cooled engines are called "screamers" by my suppliers. Yes, I know all about insulated sound dampening enclosures. ^_^
TDD
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On Sat, 03 Nov 2012 07:41:55 -0500, The Daring Dufas

With a small automotive engine..you can simply idle it at 700 rpms and have no requirement to drive it at 1800 rpm
Gunner
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On 11/3/2012 10:12 PM, Gunner wrote:

When you write "small", are you referring to a small block V8? The 10kw Generac units I installed had a 4 cyl Turkish Fiat liquid cooled engine running at 1800rpm. That speed gives 60 cycle AC power from a 4 pole generator. The 2 pole generators run at 3600 rpm. The 1800rpm speed lets the genset respond well to changes in power demand and electric motor start loads. I think it takes something like 1.5hp per kw to run a genset so a good sized engine would be needed to get that kind of power at idle speed. O_o
TDD
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On Sat, 03 Nov 2012 23:57:24 -0500, The Daring Dufas

Im thinking more along the lines of a Pinto engine or similar. When one simply changes the pulley sizes...an idling engine can spin a genny at 1800 rpm easily. How many hp is the typical small engine out of a Saturn or Pinto or similar?
the little 1.9l Saturn engine is 85hp out of the box. At idle...how long will it run on 5 gallons of fuel? 10-15 hours or more?
And they can be had very very cheaply out of wrecks and other sources. A buddy of mine built one using the HF 10kw gennhead and a Pinto engine. It runs for days on a 20 gallon gas tank. At something like 800 rpm
Gunner
Gunner
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On 11/4/2012 12:24 AM, Gunner wrote:

What is he using for a speed governor to keep the frequency stable? I know there are a lot om OEM parts used to control idle speed on modern vehicle engines that could be used to make your own governor. The HF generator could be directly coupled to a small engine running at 3600rpm using a Lovejoy coupling. The specs call for 16hp for full output so I'm wondering if you could couple it to the existing pulleys on a small 4cyl auto engine keeping the bell housing, flywheel and starter to make things easier. Of course many modern vehicle engines don't have a simple ignition system with a distributor and coil, so what could you do there. I know an old Pinto engine didn't have an ECU but a simple, possibly electronic ignition with distributor and a carb which would make for a easy conversion to a stationary engine. My old 89 Dodge van has an engine control computer and TBI which could be used to build a stationary engine for a generator but I'm wondering about the new super whiz bang computer controlled engines of today's vehicles? O_o
TDD
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On Sun, 04 Nov 2012 01:43:57 -0500, The Daring Dufas

Keep in mind..that 3600 rpm engines are using 4 times as much fuel as a 800 rpm engine. Which is why the good gensets only run at 1800 rpm. They took subsized engines, hooked them up to a genny and run them hard in order to keep the hp ratings up. Which works..but its hard on the engine and hard on the fuel bills.
The new whizbang engines do exactly the same thing with the new computers and they can be yanked out by the roots and installed on the standby, though its a bit more complicated because so few of them have a distributor anymore. Hence my suggestion about older engines with a distributor for the hamhanded or those without a decent shop manual for the engine/vehicle in question.
Gunner
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wrote:

Gunner,a Pinto 2300 peaks at 96 ft lbs at 3000 RPM At 800 RPM it would be doing VERY well to put out 55 ft lbs. 55*800/5252=8 HP Not likely it could run a 10Kw genny at full load. With proper modification you might get the torque up to 75 or 80 ft lbs. That would give you 12 HP. JUST, possibly, enough to run a good 10KW genhead at full output, and take over a gallon an hour to run, so 2 days at close to full power on 20 gallons is believeable. Running at less than half output might increase run time by 25% if he is REALLY lucky.
On a later model engine 800 RPM could possibly be controlled bretty well under low load by the idle air speed control after it got warmed up. The same engine, running at 1800 RPM would put out about 90 ft lbs, for 30 HP - and running a 10Kw generator head at full output would use about the same amount of gas because the efficiency of the engine would be higher.

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wrote:

5000 with multiport injection.
Torque at 2400 is 107 and 115 respectively.
Assuming 80% torque is available at 1800 RPM, the early engine would produce [ (.8X107)X1800/5252] ).33 Hp
The multiport engine, under the same assumption, would produce [(.8X115)X1800/5252] = 31.53 HP
Assuming 80% of maximum rated torque on an engine without variable valve timing is being quite generous, from my experience.
I'd call 25 and 27 HP pretty realistic.
Also, idle consumption and full load consumption at 1800 RPM have absolutely nothing in common. Specific fuel consumption at 1800 RPM MAY aproach 0..4 per HP Hour. That would mean ABOUT 10 lbs per hour for the low powered engine. At 6 lbs per american gallon of regular gasoline, we are looking at just under 1.5 gallons per hour, so about 3.3 hours at full load - of approxemately 15 KW with an average generator head and a reasonably well set up belt drive. At anything less than full output, the efficiency would drop quite a bit, so half load MIGHT give you 5 hours of running.
Take off the OEM fuel injection system and replace with a custom tuneable unit, and retime the camshaft to move the torque peak down closer to the running speed, and you could perhaps improve efficiency a bit and squeeze, say, 7 hours at half load out of the system.
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On Sun, 04 Nov 2012 14:44:03 -0500, snipped-for-privacy@snyder.on.ca wrote:

And if its run at an idle with say...4kw load? 15kw is a hell of a loadout. I dont pull but 2kw with just the basic...CF lights, reefer motor, and a TV or radio, plus the blower for the gas furnace. Make that 2.5kw on furnace startup.
Ill have to see if I can get ahold of Gene, he documented his usages pretty well and I know he runs his homestead on that engine/genset for about 4 days on 20 gallons of fuel. At an idle.
My genset here at the homestead is a 4kw Onan and it runs everything nicely, including the popcorn popper (grin) on about 1/3 gallon an hour with everything running balls to the wall. Its an 1800 rpm twin cylinder motor out of a wrecked motorhome.
Which btw..is another good place to find gensets.
Gunner
Gunner
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wrote:

dual fuel (propane/gasoline) Take a 12HP twin (at 3600 RPM) and run it at 1800 RPM as a 6 HP engine on a 4Kw Generator head and it is a long life unit - particularly with a full flow oil filter set-up.
The liquid cooled systems are significantly quieter than air cooled - and a lot of the higher end motorhome units are moving to liquid cooled. More expensive though.
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On Sun, 04 Nov 2012 14:44:03 -0500, snipped-for-privacy@snyder.on.ca wrote:

Oh...I went to sleep one night with my 3.0 Ford Ranger idling out front and didnt remember it was running..and 2 days later, got ready to go to work...walked out..and my truck was running. Used about 3/4 of a 14 gallon tank of gas.
Just a heads up.
Gunner
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On 11/4/2012 3:20 PM, Gunner wrote:

There was a well known party girl here in town who'd get sloppy drunk and not remember where/what went on many nights. She left her little Toyota idling outside of the local hangout over a weekend and found it Monday morning happily idling in wait. I never walk away from a vehicle unless I secure it and lock it even if I'm letting it warm up. ^_^
TDD
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