Tapping power from a gas engine to light an LED 9

[paskee]

Hi Guys,

I am an Agicultural Engineer (Irrigation & Water Mngt).. and I'll highly appreciate any help/advice you can share on...

I operate on a farm (in the Philippines) several gasoline (anywhere from 6 to 10HP) "pull start" (rather than battery start) engines that drive water pumps. These pumps/engines are operated during the night (it is pitch black!). While the engines/pump are in line of sight, they are located far (100-400 yards) from where we can view them. At present, we do not know wether the engines are ON or OFF unless we inspect them regularly and individually.

Since combustion in the engines is done thru "spark plugs" and a magneto, is it feasible and practical to tap some current from the ignition system to power an LED ?
If so, will it significantly degrade the engine's efficiency?

Thank you,
Paskee
PS. I can get the engines wiring diagram from the manufacturer.

 

[waross]

Find some place to mount a bicycle generator. If there is space under the flywheel to mount a second magneto coil that would be a better place to draw power.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[VEBill]

A neon bulb can typically be capacitively coupled to the spark plug wire, and made to blink with each spark. But it would be too dim to see from any distance.

What about the oil pressure switch? Most engines of this type would have an oil pressure switch to kill the engine if it runs low on oil. Tap into that signal, determine its characteristics, and take it from there.

 

[paskee]

Thanks Waross,

I will try your idea.. in fac .. the engine is coupled to the pump by a pulley/ belt configuration and I can place a smalll bicycle type generator to interface w/ the belt ... my reservation however is that a 2nd magneto is a mechanical solution, another thing that can break ... which we try to avoid as much as possible in the field... good thing is that its not a critical component of the engine/pump function.. I will inform you of the results in a month or so.. Thanks again..Paskee

 

[paskee]

Thank you VE1BLL,

I like your suggested solutions.."wire and bulbs":

a.the spark plug tap - the blinking effect is wonderful (easier to see and possibly extends the bulb life).. my thought is however to tap before the spark plug capacitor (on the main magneto) rathar than after (where it could possibly degrade the electrical inout to the spark plug and effect its function)

why NEON ... I did a cursory search, I did not find any advantage over LED?

b. the oil switch ... you are correct, a few of the engines have thie feature ..

I will ask the manufacturer ( Briggs and Stratton ) about both these solutions, snd what maximum power I can draw w/o affecting the engine.

Tahnks again VE1BLL...Paskee

 

[VEBill]

LEDs (being semiconductors) are naturally more sensitive to high voltage spikes (but reportedly not as sensitive as one might think). Neon bulbs (e.g. NE-2) would probably be more forgiving in a spark plug driven system.

For low voltage applications, it's gotta be LEDs all the way.

 

[cranky108]

I some lawn mowers where there is a battery start, they use a sort of second magneto to charge the battery. I assume the windings may be different to gain a lower voltage. The problem is this fixture is part of the casting of the engine like the magneto (or the bolt holes would be).

The bicycle generator is somewhat inexpencive, which make it a good solution.

Most neon bulbs have a 90V conduction voltage, which is why they work well for high voltage. The current demand is also small, so a resistor is placed in series to drop the voltage. Most LED's have a turn on voltage in the 1 to 2 volt range, which makes them a little more problematic.

 

[dpc]

I like Bill's idea for the bicycle generator.

 

[MadMango]

LEDs run on DC, so you'll need a rectifier.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[paskee]

HI Guys,

The bicycle dynamo (runs by friction )probably will not work. I just called a mechanic at a bysycle shop..he said the bicycle dynamos were built tor maximum of 200 rpm.. an engine running at 2000-3000 rpm will smoke the dynamo. It means placing a reducing wheel to accomodate the speed.. that is another part/complication.

Also, they are expensive.. $100 for a dynamo(hub based) LED combination ! the engines they are running cost brand new about $300.. it seems a mismatch.

Thanks.. Paskee

PS.. The electrical solution ( I hopw it turnss out to be inexpensive). My thinking was small LED flashlights are so inexpensive ($5).. that I can get away with some wires and an pre-mounted LED light .. we have about 17 engines nad my farmer neighbors can benefit too from a solution.

 

[bradrs]

So the purpose of the LED would be so you could look across the field and see if it is running? Does that mean you now have to have someone looking at the lights regularly? Or how often do you inspect to ensure that they are operational?

If I were doing this, my thought would be to have an alarm to alert me when an engine was off, instead of constantly having to go monitor for lights at each one. Maybe even set it up so that you are monitoring what the engine is doing(water pressure/flow I presume?), and that way you can catch issues aside from engine running.

Seems like a simpler solution would be to go on a walk around the field every so often

 

[telecomguy]

How about reflectors and a spot light. Put a reflector on the pulley and hit it with a spot light. If its spinning you'll know it.

 

[paskee]

Hi BRADRRS,

If we have 17 engines, and view (via binoculars) that a light that is supposed to be on on say location #6 is OFF..we will know that that engine is not working and then go out and fix it. The farm is about 20 acres. It takes anout 1.25 hrs to walk the periphery during the day, about 2.5 hrs in the night ( there are no roads or walkways.. just small paddy embankments..about 1 ft wide, earthen (snake risk, too!) .. and it is pitch black. It is third world situation, no electricity, etc.) Pressure, water flow is not a big concern.. just if it is running or not.

BTW... you presented a GREAT idea.. why not produce a signal when it is off (not when it is ON).. since the engines are running 95% of the time.. we save money by turning on an LED/or NEon bulbs only 5 %.. then batteries might work!

Thanks you... Paul

 

[paskee]

Hi Telecomguy,

Your spotlight / reflector idea ... kinda far (400 yards) and electricity is not available.. I got to power the spotlight w/ batteries

Thanks..Paskee

 

[davidbeach]

I think bradrs is on to something. Far easier to tell if one light is on than to tell that only 16 out of 17 are on, particularly if there isn't good and consistent angular separation between them from the observation location.

 

[itsmoked]

You can go four ways. Two of them would be energy harvesting.

1) A generator. It can be any really small dc motor recharging a battery.
2) Thermal harvesting using the rejection heat of the exhaust.
3) Vibrational energy harvesting using the engines vibration.
4) Lastly would be solar. You could use the typical junker solar lights and use a vibration or pressure (water) switch to turn them on and off.

In all cases you'd want a simple blink of a high brightness LED pointed in your direction.

Now if we can just find an applicable product ready made.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[IRstuff]

I'd go with Keith's last option, but add to the possible sensing modalities, exhaust temperature. Therefore, a standard backyard solar light that turns on when the exhaust temp drops below a set value, and the battery can be recharged during the day.

TTFN
faq731-376

 

[paskee]

Hi Itsmoked/IRStuff,

Thank you.. but, I am looking for a $10 solution! .. Paskee

 

[waross]

If the engines are available with an electric start/battery charging function, then changing the magneto coil to a unit with battery charging capability will give you a usable voltage. One unit may be used to power several nearby pumps if you go with a battery and a lights on for failure solution. A sail switch in the cooling air flow may be cheap to make. Use a piece of plastic sheet glued to the arm of a limit switch.
I hadn't thought about exhaust heat. If you buy some TC extension wire you may construct some thermo-piles that will generate enough power and voltage to light an LED when the exhaust is hot.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Skogsgurra]

I would put a piece of 3M reflex tape on a paddle that gets turned away by exhaust gases and turned back in your direction when engine stops. You can scan the field with a bright LED torchligt and binoculars. If you see bright reflexions, you have engines that do not run.

Gunnar Englund

http://www.gke.org

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