Author Topic: Dumpster Diving Heaven (Read 10016 times)

dinges · « **on:** July 14, 2006, 04:52:45 PM »

Right. For a while I've been looking for an old gas lawnmower for the engine, to build a small gasoline powered generator (12V & 220V). The prices for such old junk were still ridiculous (50E or more).

Then, today, I went to the dump to get rid of some stuff. Saw this beautiful (to me, at least ) lawnmower standing there, as if begging to be given a new good home, a 2nd life. As no one was looking, I performed my trick.

Turns out she still runs fine. All the mechanical bits of the motor are fine, only the blade was rusted away. No problem, she won't be cutting grass anymore. Blade has been removed and still runs fine (some need the blade as a flywheel).

What I was having in mind, for a while, was a genny as described here:

http://theepicenter.com/tow02077.html

Admittedly, not really RE, but possibly good fun to build and handy to have.

Was planning on adding both a 12V car alternator and a 220VAC generator. As to the last one, I understand synchronous motors will work. But I was wondering what they use as generator for 'real' (i.e., as built by Honda) small gas generators. Are it standard induction motors with an extra cap? Permanent magnet alternators (like our motorconversions)? Or something else? And, to they automatically adjust motor RPMs for varying load?

The motor is 3.5HP (2.4kW), 3000RPM (measured up to 3700RPM, full throttle without a load). All that's to be done is weld a small steel frame and mount a car alternator with a V-snare. As for the 220V genny, still looking for good advice on that one. Would a motor conversion (say, 3phase, with permanent magnets) work, as long as RPM is tightly controlled to be 50-60Hz? Perhaps that way I could even have portable 3phase? Admittedly, 3.5HP/2.4kW is not much, but it would become a small, portable powerplant for emergencies. Maybe a 'training project' for the next, bigger one (5-7.5HP, if I find a motor).

I'm even toying with the idea of adding an electric starter (not needed, but would be nice, no?) with a small 12V 12AH battery for starting. Probably too difficult to implement, but we'll see.

Peter.

Nando · « **Reply #1 on:** July 14, 2006, 11:43:29 AM »

Since it is a 3600 RPM motor, couple it to a 4.5 to 5 HP INDUCTION motor and add biasing capacitor to make it to produce AC, it may produce around 1.5+ KW, much higher than the alternator and easier to handle -- directly to the house --.

ALSO with a pulling solenoid ( to control the gas) and a PWM controller one can maintain the motor to maintain the 60 Hertz and if the right Capacitor value is set the output voltage will be kept to the RIGHT value with different loads.

Nando

ghurd · « **Reply #2 on:** July 14, 2006, 11:54:54 AM »

Buy an inverter.

Not what you want to hear, but it won't take a lot to stall the motor.

I believe you will have a hard time getting 400W, maybe even 200W, of electric out of it, direct, at any kind of stabile RPMs (Hz). A small load really drags them down.

In the US, a cheap rebuilt auto alt is for a '73 or '76 Chevy pickup. US$30.

Not too powerful, but more than enough to stall a 3.5 B&S with a low battery.

I expect you will build some fancy circuit to control or limit the amps?

It is common here to use a circuit that sets the charging amps (not the volts).

A factory auto alt will get the battery to 14V (whatever) in a couple minutes. After that, the charge current drops to 'not much', then its a waste of gas.

It is therefore common to charge a low (like 10.5V) 85AH battery at 20A for 5 hours.

Ouch. Yes, Bulged batteries are common too.

Its also common to use a much too long and much too small gauge wire from the alt to the battery. Like a resistor, the V drop increses with higher amps, tricking the alt into not stalling the motor. The wire can get HOT!

(Hey- It wasn't my idea! I'm just saying how its done around here.)

G-

gotwind · « **Reply #3 on:** July 14, 2006, 12:07:04 PM »

Nice find.

Unfortunatly in the U.K, we are not allowed to remove items from the council run dumps.

Something to do with halth and safety - seems daft to me.

A boy of 16 was fined £50 ($90) for removing a 16" bmx tyre.......

I've seen loads of great items that could be recycled - bikes,lawnmowers,motors, copper cables e.t.c. They will just go into landfill I expect.

The worlds gone mad, well our little island has.

Ben

dinges · « **Reply #4 on:** July 14, 2006, 12:11:39 PM »

Thanks Nando.

Is this what commercial generators (for 220VAC) do too? We have one of those (2.2kW electrical), but it looks just like a plain electrical motor to me.

I understand that with induction motors as generators, one shouldn't let the generator stop under load, as it will not generate when restarted; it would need to be 'flashed'.

So, that's why my question of those commercial generators; what do they use, that they can stand being stopped under load. I've been thinking, would adding a small neo magnet anywhere on the rotor help in getting proper startup (even after it has been turned off under load). Don't know.

Did a bit more of a search on the web, but found very little interesting stuff, apart from the previous link of the epicenter (see original post) and this one:

http://www.qsl.net/ns8o/Induction_Generator.html

Thanks for the reply.

dinges · « **Reply #5 on:** July 14, 2006, 12:35:22 PM »

Ghurd,

You're right, not what I wanted to hear, so I'm going to conveniently ignore you

You serious, a 3HP (2.4kW) motor stalls when loaded by 200-400W of load? Or at least RPM drops enough below 50Hz to cause trouble? I've always wondered how those commercial gas generators controlled voltage & RPM (controlling the gas motor)

As for the charge controller, I've seen a design in homepower magazine that described a similar project, old lawnmower motor with 12V car alternator. Was thinking of using that circuit:

http://www.homepower.com/files/mark8.pdf

Not sure on what to do though. Voltage control? Current control? It would be nice to use this gadget as a portable emergency welding machine too... As you can see, it's all still in the brainstorming stage.

Am going to install a car alternator, that is sure. But I thought it would be nice to have 220V present as well, if it's not too difficult to build (or with silly rules, of not letting the generator stop while under load). A small battery and inverter might be an option.

The wheels will be re-used too. Should make the new contraption a bit more portable/draggable.

BTW, the gas cap on that lawnmower... NOT 3 clicks! Great.

Gotwind,

We have similar laws here in The Netherlands. Don't get me started on those silly (read: stupid) rules. Guess I'm being naughty. Feel sorry for that kid though. It's a lot of money for a 16-year old. Hope he's less of a cynic than I am, otherwise he could really ruin the atmosphere in his class when they cover the subject of 'recycling/caring for the environment/etc' in his class. Say one thing, do another. Gotta love hypocrisy. Keep repeating the political correct tantra of caring for the environment, but punish those who actually try to make a difference. </rant>

Peter.

Nando · « **Reply #6 on:** July 14, 2006, 12:45:37 PM »

Yes those generators are induction motors with an extra winding and a capacitor for Flux generation.

Also 2 small magnets will do the trick to start/stop under load, though some DO have a relay for that purpose -- which that from my point of view should be the best arrangement to have.

Nando

dinges · « **Reply #7 on:** July 14, 2006, 12:53:18 PM »

Now it's getting interesting...

You mean if I place 2 small magnets (where? N vs. S diametrically opposed on the rotor?) in the rotor, it should always start generating reliably? This sounds very interesting.

What's the relay for? Not sure I understand where this comes in, or why you say this would be the best arrangement. Better in what respect?

As for the extra winding and a capacitor: so, it's basically a normal 1phase induction motor? All 1phase induction motors have a (rudimentary) 2nd phase with capacitor connected to it, right? But, you say 'ALSO 2 small magnets...'. Does this mean that just the 1phase motor with 2nd phase & capacitor would be enough too? I understand that in that case, it would stop generating when stopped under load.

Flux · « **Reply #8 on:** July 14, 2006, 12:59:17 PM »

Peter you love projects, it's a total waste of time but if you have fun it will keep you happy for months.

Vertical shaft is a pain, no useful governor is the biggest issue but a servo should fix that. Those engine figures seem to be based on a 1mS rating or something, an electric motor is expected to stand 20% overload for ever, those engines pass with flying colours if they get 90% for a second. They last 10's of hours at full rating.

What do Honda do, they generate raw ac , rectify and invert to fixed frequency ac and alter engine speed to match the power.

What do the others do? they fit accurate governors and usually use a capacitor excited synchronus alternator, hard saturated to keep volts a bit constant and prey that you use a resistive load, the go flat at the thought of a reactive load.

Welding with less than 8hp and a 10kVA alternator, dream on.

Either use a car alternator and inverter and not worry about speed or adopt Nando's idea of a capacitor excited induction generator, it's close to fixed frequency and your servo speed control can use output frequency. The volts will not be quite as stable as the synchronus machine and the reactive load capability will be even worse.

For the next project convert the motor to a synchronus alternator with field windings slip rings and AVR. By then the grass will be long and you fit the engine with a new blade and use it to cut the grass, something it is moderately good at.

Project yes ,fun yes, tool maybe if you get that far.

Flux

ghurd · « **Reply #9 on:** July 14, 2006, 01:23:58 PM »

You can't ignore me. I'm a PITA!

Yes. A 5HP Honda (again, common and probably the do-it-all motor here), a factory 40~60A auto alt, and a 10.5 or 11.5V battery will result in a stalled motor. Every time.

Some guys get around this by restarting the motor at top speed and reconnecting the battery... again and again and again... until it stays running.

I can't get the link to work. Saw it before but can't recall what it does, or how.

As you know,

The factory alt is mostly voltage controlled and has its problems. And a current control has its own problems.

There was a combination of the 2 somewhere on the `net, but I thought I saw problems with the basic design concept and never pursued it further.

I expected it to look like this...

http://www.otherpower.com/images/scimages/5769/VanDeGraaff.jpg

Besides, it had a bunch of those 8 and 14 legged chips I hate so much.

hiker · « **Reply #10 on:** July 14, 2006, 01:40:05 PM »

put a bigger pully on the alt--your engine will no longer stall--not to mention its hard on the motor to over load it..you dont need 3000 billion rpms just to charge a batt.

whatsnext · « **Reply #11 on:** July 14, 2006, 01:59:16 PM »

The other solution is to redesign the voltage regulator so that the alt is always trying to go straight to full power. 1 hp=750watts so a 5hp motor should be able to put out 3.7kw or so. I would think keeping the B&S governor would be all you need to keep the rpm steady as long as the alt is not trying to do too much. Where's Amanda and the other electron genious' when we need them?

John...

whatsnext · « **Reply #12 on:** July 14, 2006, 02:00:12 PM »

"is" should have been "isn't" in the first line.

ghurd · « **Reply #13 on:** July 14, 2006, 02:00:42 PM »

Forgot. The last few 115VAC 60Hz gens I looked at...

A couple old ones had weights and/or springs or the standard for RPM / Hz control.

A few new ones (chineese) had a stepper motor direct connected to the carb. Sounds like a good idea... until you try to use one. Like with a saw or pump.

One had a intake manifold vacuum line to a "do-hicky". It looked (to me) like the vacuum controlled the speed. Makes no sense to me, but I couldn't find any wires, though I did not take it apart.

Honest. I haven't seen it work as well as often advertised. And there are thousands of the 12V ones around here. No BS.

I would go with a battery(-ies) and inverter. Then not let them get below about 12.2V. Run the motor / alt before, during, and after a large inverter drain.

And do not expect the alt to keep up with half the drain... just in case.

G-

whatsnext · « **Reply #14 on:** July 14, 2006, 02:29:55 PM »

I guess I should have mentioned that even with a 70A alt you would only be using about 1/4 of the available power of the engine. It's stalling because the governor just can't react fast enough so a 'softer' voltage regulator would allow it to keep up.

asheets · « **Reply #15 on:** July 14, 2006, 02:35:50 PM »

Here's a document on how to do this with an induction motor -- http://www.qsl.net/ns8o/Induction_Generator.html

ghurd · « **Reply #16 on:** July 14, 2006, 02:37:14 PM »

"redesign the voltage regulator so that the alt is always trying to go straight to full power"

That is the entire problem in the first place.

The second problem is figuring a 5HP motor can somehow make 3.7KW of electricity,

because it can't. And never will.

"a 5hp motor should be able to put out 3.7kw".

A common thought. Not a snowball's chance in Las Vegas (slightly hotter than hell).

The guys using these things I am talking about figure a 1/2HP electric device needs 1HP minimum of gas engine to run it (straight from the gas enigne to the device).

AND they figure a 1HP electric device needs a 5 or 6HP gen to run it with electricity.

Countryboy · « **Reply #17 on:** July 14, 2006, 02:47:43 PM »

Most lawn mower engines come from the factory with a governor on them.

The flywheel has fins on it, which move air. There is usually a spring loaded plastic fin about 5 or 6 inches long beside the flywheel fins, which is attached to the carburetor. The flywheel fins blow air against the plastic governor fin. RPM changes result in more or less air blown against the plastic governor fin. When RPM drops, the spring moves the fin closer to the flywheel, which causes the carburetor to throttle up. When the RPMs go up, the air being blown from the flywheel fins move the plastic governing fin, which in turn throttles down the carburetor.

Match the pulleys properly so engine RPM is correct with alternator RPM, and you should be in good shape.

BigBreaker · « **Reply #18 on:** July 14, 2006, 02:55:37 PM »

You could mount a small single rotor plate to the engine shaft. Put some neos on the rotor and have them face large flywheel (conrete maybe?) with a second plate setup to drag against the engine driven rotor. Connect your alternator directly to the flywheel and laugh at inductive loads. Make the magnetic clutch soft enough that the engine won't stall and you'll have nice little setup. As long as the welds don't need long blasts of current you might get away with it.

jimjjnn · « **Reply #19 on:** July 14, 2006, 02:57:35 PM »

How about buildind a dual axial genny for that engine?

Requires less HP to run and you can build it for the engine speed that you want and voltagewhat you want. Maybe I am blowing smoke. Dont really know as I am not in a situation to build one myself. Sure do enjoy this board and all the great and not so great ideas. The guys here really are helpful and oft times comical. Love it and keep up the banter.

whatsnext · « **Reply #20 on:** July 14, 2006, 03:26:15 PM »

If that is the case then gas engine is wildly overrated. Also note that I corrected my own typo so that 'is' should have been 'isn't'. The idea that 1hp gas = 1/2hp electric or some other number is just nuts. It's only used because most don't seem to understand the difference between torque and HP or starting amps and running amps. Since electric motors usually have high torque people think they are equivelent to larger gas engines and they are not. And because the reequire high amps to start people think you need a much larger gas engine when you don't. HP is HP. The idea that 1hp electric requires 6 hp gas to operate to run is absurd UNLESS you have extreamly high losses OR large starting current so you are seeing short term high wattage. A large flywheel would cover for that or a softer start would do the same.

"a 5hp motor should be able to put out 3.7kw"

This is not just a 'common thought' it is the conversion of hp to watts. It would require 50% losses to only put out 1.8kw or so and those losses would have to show up somewhere like things melting from waste heat or it's not really 5 hp. A five hp briggs is rarely putting out five hp because it is rarely running at full throttle at it's optimal rpm not because gas hp is somehow different from some other hp.

John....

dinges · « **Reply #21 on:** July 14, 2006, 03:28:26 PM »

Thanks for the replies, all.

Ghurd, I'm still a bit surprized by the statement that a 5HP gas engine can't deliver, say, 3-4HP of electrical energy (accounting for some conversion losses). I always thought that a Watt was a Watt. You happen to know what's going on here that makes comparing gas-HPs to electrical-HPs similar to comparing apples and oranges?

The homepower link works fine for me; have you tried to 'save file as' (right-click)? I'd be interested in knowing if this was the thing you had in mind that would generate sparks like that VanderGraaff generator (another looney Dutchman )

Was planning on building a charge controller like that mark8 in homepower magazine.

As to induction motors, to Nando: if I have a single phase induction motor, that normally requires a capacitor over an extra winding to run properly (the start winding), would this be enough to use as a generator? Perhaps by replacing that capacitor with one that's intended for continuous duty?

BTW, none of the single-phase induction motors (with 2nd phase for starting and a capacitor) that I've seen over here do have a mechanical mechanism to disconnect the startwinding as it's running full speed. I remember seeing several pictures of American single-phase motors that do have some mechanics that switches off the start winding. Like I said, I've never seen such a mechanism myself here, in Europe. Puzzling.

Peter.

Flux · « **Reply #22 on:** July 14, 2006, 03:30:43 PM »

Just to clear up a bit of confusion about the capacitor excited alternators that generally go by the name of brushless alternators.

They are not induction machines, they have a winding on the rotor and a diode. They are true synchronus machines and there is no slip frequency.

You say you can't find much about them on the net, neither can I. I think the basic machine was invented by Nonaka ( Japan I think)

This is basically how they operate. A good way to think of a single phase induction motor is to regard it as having 2 rotating fields rotating in opposite directions. The net result is a stationary pulsating field.

These motors are not self starting, but if you mechanically start it in one direction you upset the balance of the 2 fields and the rotor follows one field and runs just slower at slip frequency. In relation to the rotor you can consider the other field to be rotating at twice line frequency ( 100 or 120 Hz).

Now if you replace the cage rotor with a salient pole winding with a coil closed through a diode you can extend the concept to these generators,

If you spin it with a prime mover and you have a capacitor across the stator winding it will excite as an induction generator and the stator winding will carry the pulsating field as for the single phase motor. As you near synchronus speed the rotor will be running near the speed of one field and will have a bit of induced volts at slip speed but that does nothing as there is no cage winding. What matters is the other field rotating at 2 x line frequency with respect to the rotor. this will induce a voltage in the rotor winding and the rectifier will cause a dc current to magnetise the rotor as in a conventional machine with field fed by slip rings. The magnetised rotor makes the machine into a wound field alternator and this produces the main voltage in a second winding wound at right angles to the capacitor field.

The main winding is wound to produce the line voltage of the system. The capacitor winding is usually wound for a higher voltage to use smaller capacitors.

Capacitance values are chosen so that the capacitor winding just about saturates the core at nominal speed.

Regulation is poor compared with a machine with AVR or a self excited compounded machine ( very old technology) but is good enough for most portable things such as tools and lights.

Voltage is highly speed dependent and they work best with engines with good governors. They are happy with capacitive load but don't like inductive loads. They are not the best for starting induction motors and welders either flatten them or blow the field diode.

In many ways they are not much better than self excited induction generators but they are synchronus so the frequency is a little better and they are a bit more stable in voltage with odd power factor loads.

They tend to have better residual magnetism in the rotor and nearly always build up with no problem.

Flux

dinges · « **Reply #23 on:** July 14, 2006, 03:41:17 PM »

Flux, thanks for the explanation. Not sure that I fully understand though, so will have to read a few more times. I'm having difficulty suppressing the urge to dismember that generator head on our commercial genny, to see what's in there...

In the mean time. The single phase induction motors (with a 2nd phase for starting, with a cap) must be a different beast than the Nonaka motors. They have no diode and no coil in the cage. Just a 2nd phase with a cap. You think they'd work as generators?

Man. I really hate having this guess work and having to ask these stupid questions, when all I need is a good (online) text or textbook that explains it all with some nice graphs.

Thanks for bothering to answer though.

Flux · « **Reply #24 on:** July 14, 2006, 04:14:28 PM »

Single phase induction motors are just that. They have cage rotors.

The Nonaka alternator is not a special motor it was developed as a true synchronus alternator. I used the single phase motor analogy to explain the idea.

Your single phase motor will at best make an extremely poor induction generator.

If you want an induction generator use a 3 phase one and balance the load round the phases.

If you must use it single phase then use the 2 capacitor set up like the small hydro boys do.

Yes Hp is Hp. If the load is right you will get the same power from an engine as an electric motor. Torque characteristics are different and so are the overload characteristics.

A typical electric motor will give 3 x full load torque, a good engine will give full load torque only.

An electric motor will likely sustain 20% overlaod indefinitely and not show it.

Cheap engines will maintain full load for a few minutes.

The main reason why the difference between engine power and car alternator out is so great is due to the dreadful alternator efficiency, belt losses and the unsuitable regulator characteristics forcing the field current to maximum.

Flux

bob g · « **Reply #25 on:** July 14, 2006, 04:22:57 PM »

wild in alaska has it right on the money

go with a larger pulley on the altenator, you will get far more useful output without spinning the crap out of the alt and loading the engine too much.

set it up to charge a battery and then feed an inverter, the battery will help to deliver the large amp shot for starting loads without stalling the motor.

to understand the gasoline lawn mower engine one has to take a look at the hp/torque curve, they develop 5 hp at 3600 rpm, anything under that the torque curve falls off and its ability to deliver 5hp goes away very fast, at 3000 rpm i would be surprised if a 5 hp motor could deliver 3 hp.

geared properly the little engine can stay up close to the 3600 rpm mark and peak hp, you may then get 1.5 to 2 kwatt out of it, but it will be a stretch to get the 2 kwatt.

going the battery inverter route you can get higher surge capacity and a better more stable machine i would think.

also consider 1/4 turn drives and your belts, ala corvair, idlers can be used to make the turns and get the alternator upright where it belongs, also with a 1/4 turn

setup you can get the alternator to turn the right way to optimize the fan and air flow, crucial to keeping the alternator alive long term

bob g

dinges · « **Reply #26 on:** July 14, 2006, 04:36:45 PM »

Thanks Bob,

Figure I will have to play around a bit with pulley sizes anyway to match the alternator to the load.

Hadn't yet considered the right rotation direction for the car alternator, but yes, you want the wind to blow in the right direction for cooling.

On the other hand, a small B&S motor isn't meant to be run 24/7. Don't think I'd feel happy letting it run for more than an hour or so. Small gas engines are nice things, but they do have limitations. Maybe a few 100 hours of total lifetime. 1000 hrs at best?

Perhaps instead of the 220V alternator, I may add a 24V truck alternator. My future RE system will probably be 24V anyway (or 48V).

Decisions decisions...

RogerAS · « **Reply #27 on:** July 14, 2006, 06:00:40 PM »

dinges,

As I write this my honda 5.5 hp gx160, horizontal shaft, is turning a 100 amp Ford non regluated alternator. I have it set to produce about 30 amps continuously. The motor is running at about 1/3 to 1/2 power, or throttle. I am using about .5 gal per hour of gas at this rate, maybe less. I have a Browning two part 5" pully on the engine and the standard pully on the alternator. (I want to go with a 2 belt setup on this, but haven't yet). I only run this setup when a. I'm trying to cool the house from the opressive Arkansas heat via a small 110V 2500 BTU AC unit, or b. when there has been less sun or wind I need to keep my battery banks up. The inverter powers everything, not the alternator to AC directly.

I just use a headlight pull switch from an old junked Ford Ranger PU to control the output. Inside one of these, and lots of older cars have that type switch, is a coil of resistor wire and a wiper for dashlight brightness control. I have a relay with a switch both in the engine room and in the house to supply power to the rotor. From the relay this DC is sent through the variable resistor and then to the rotor. The variable resistor allows me to adjust the output of the alternator. When I do this I keep a VERY close eye on the battery voltage, and NEVER let it run unattended.

I have 2 amp meters. One is the current going into the batteries, and another on the inverter side to monitor drain. I try to never charge with the engine more than 10-20 amps more than I use, and then ONLY if the voltage is low. Right now it almost balanced with maybe 5 amps more input than use. This is a 1320 amp hour bank.

With this setup I do have to keep an eye on things, but it gives me way more options than a self regulated alternator would. If I need all the power the engine-alternator will produce I can do that, or just idle along at a few amps output. I get better use of fuel and the belts, engine and alternator last a nice long time.

Someday I hope to have enough PV's to run the damned AC without burning fossil fuels but can't right now. I would like to use producer gas when I HAVE to run an engine, but that's also out there in the future. I have 60 acres of hardwoods to draw on for that fuel, and am surrounded by thousands more. Oh it's nice, but hard on the wind harvesting without a very tall tower.

Anyway, hope this helps a little.

RogerAS

americanreman · « **Reply #28 on:** July 14, 2006, 06:02:26 PM »

First of all if that motor does not have a heavy cast flywheel it will not work very well or if at all for what you are trying to do.

This mumbo jumbo about stalling out is just that, get a rheostat for the field wire on the alternator and adjust the field as necessary.

Car alternators are best for these types of applications because they take the vibration of the motors well. Most likely you will mount the alternator as if the shafts were joined by a coupler to acheive the proper rotation for cooling, check your fan and be sure.

I've been building these since 1980 and they work great, I can't beleive the naysayer posts here on this one, you can get a great charger from these, alternators were designed to charge batteries.

Let's get a little more indepth, generators are a great way to go also, from tractors or old cars, buy them rebuilt, it will cost a little more but you have the ability to also start the motor plus put 20, 30 or more amps into the battery. Combining the 2, alternators and generators on the same motor can be a benefit too but you have to do some calculation on the pully sizes, you can get the generator to start the motor when the battery voltage drops to a point.

Best thing to consider is the rpm, I have built some where I put a pulley on the engine that is the same size as the alternator giving a 1:1 ratio, at about 100 rpm you can get a 3rd or so of the alternators rating and the motor will run all day on a few gallons of gas.

The Honda's I buy now are pressure washer take-offs with low hours, they are fuel efficient as hell, especially run at about 1000 rpm, quiet with no vibration, you can get them for 120.00 if you look around and they last a long time.

get an inverter as some have suggested, don't try to put out 120 or 240 from these setups and buy at least a 4.5 HP motor.

If you decide to crank it up to 300 rpm, a 5 inch pulley on the motor is about right, try the 1:1 method with a rehoastat, you won't be dissapointed, but you won't get the alternators full output either, but great for charging batt's.

Hope this helps, I run my cabin and my boat on a setup like this.

americanreman · « **Reply #29 on:** July 14, 2006, 06:06:16 PM »

Sorry for the typos, thats 1000 rpm, not 100 - and 300 rpm, not 300, should have previewed ;0)

whatsnext · « **Reply #30 on:** July 14, 2006, 06:58:02 PM »

This advice is the correct one because we've seen these work perfectly not withstanding Ghurd's comments. There is absolutely no reason for it not to other than a normal alt having a somewhat inapropiate voltage regulator. Redesigning the voltage regulator seems to me to be the most direct aproach because it would allow the small engines governor to work on it's own but just running the alt slower works as well.

John..

dinges · « **Reply #31 on:** July 14, 2006, 08:07:34 PM »

Hi Roger,

Thanks for the reply.

Could you post a picture here of your setup, if it's not too much trouble? Maybe I could get an idea or two from those. The wooden rack in a previous picture in this thread is exactly what I had in mind myself, using two wheels and a handle. Only I would make it out of either stainless steel or plain steel.

With your setup, you have to keep an eye on things. Which is always a good idea with gas operated gear anyway, whether DIY or commercial built. The setup you have sounds a lot like what is described in the homepower article (see link above, which works fine for me, Ghurd) for the mark8, where they initially used a rheostat to control power to the rotor. Simple & no-nonsense stuff, only you have to keep an eye on things.

Like I said, I intend to build the schematic from homepower magazine, but I'll modify it so that I can give full power to the rotor, for maximum output. Will add an amp meter to to monitor charge current. Would like to add 2 DINSE plugs (fast-connect connectors, normally used in welding) for quick hookup, but the price probably will be prohibitive). Probably a few circuit breakers as well. Lightbulb here and there to indicate status.

BTW, it's because of help & information like this that I'm glad you decided to return to the board. Remember having visited your website (gobblerguns) about a month ago and being impressed.

Peter.

Ungrounded Lightning Rod · « **Reply #32 on:** July 14, 2006, 08:24:22 PM »

GM was playing with direct vacuum -> throttle actuator idle speed control when I consulted at Rochester Carburator, back in the early days of emission controls. Worked fine until somebody hit the power brake and its use of vacuum fouled up the feedback loop and the engine stalled.

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