[ilangop]

Hi, The speed of engine depends on the frequency of AC required by you. Our domestic house hold appliances are designed for 50Hz. The frequency of AC alternator and the speed are related by speed = 120*frequency/no of poles. For a 50Hz requireement and to run an engine at 1500rpm you would need a 4 pole alternator. (Hope electrical engineers here do remember this). And the required KVA depends on your domestic load. If you want to restrict you domestic load based on the engine output power try to know the engine power at 1500 rpm, and go for an alternator with a little bit of higher capacity, so that the engine runs at the most efficient load point for 1500 rpm. No harm in coosing an alternator equivalent to the peak power of engine, as you are only increasing the safety margin by a large extent.

For petrol engines and mechanically controlled diesel engines, you could go for a simple mechanical governor connected to the throttle control (if petrol) or fuel pump. In case you have the mpfi or crdi option, you could connect the ECu to a diagnostic tool and set the idle rpm to 1500.

Apart from this you need to have a mechanism such that the electric lines gets connected with the load only after the main line is disconnected and also after the engines reaches 1500 rpm.

Construction wise you would need to have a chassis built to accomodate the engine and alternator, and a rubber cushioned mounting is very essential.

[Gasolinejunkie]

Originally Posted by muneemmk

Have heard about buses using a second engine in the rear to power the Air Conditioner(In Leyland,Tata) so that there is no power lose while in normal driving conditions.

Apologies for going off-topic here. But even I always thought that most modern buses like Volvos and the new Tatas used 1liter diesel engines to power their AC compressors. One fool told me that the Honda City has an auxiliary motor to run the Compressor and other accessories.
Then when I was studying climate control in school I put this question forward and was told that it would be totally ludicrous to have a second engine to run something else. Almost everything that is run off the crank (alternator, AC compressor, water pump, pws pump) robs power from the engine, and to compensate this the idle speed motor increases the idle everytime the compressor turns on or the steering is turned to lock. And even though you might feel the loss of power the engine can cope with it.
I’m not saying you can’t put a second engine in, nothing in impossible mechanically. Its just not worth the trouble to mount another engine with a primary drive clutch and then connect that to a compressor. (Its way too much torque as well). Remember its not just the engine that has to be mounted - what about the fuel tank, fuel pump & lines, exhaust, electronics (however basic it might be), battery?

[Spitfire]

No problemo senor.

Sell this

Originally Posted by drkunaldas

i have 99 model santro which is due for replacement in 5-6 months time.

To buy this

they have a power generator div which deals in 5-400 KVA engines / power supply. a 15 KVA (18 BHP) genset costs around 2.5 lakhs for running 10 tubes, 2-3 AC's etc(that's quite a lot)
so i thought,

[BaCkSeAtDrIVeR]

Originally Posted by drkunaldas

See i was looking for a inverter / generator for my house.

You will get 4 stroke LPG gensets from Shriram Honda. In addition to be very silent (you need to choose such silent models in enclosures), it will be far less expensive to run.

...KVA (18 BHP) genset costs around 2.5 lakhs for running 10 tubes, 2-3 AC's etc(that's quite a lot)
so i thought, i have 99 model santro which is due for replacement in 5-6 months time.

As already advised, sell you car as a whole. It spews out 40-60 BHP even at half its normal RPM.

@ BaCkSeAtDrIVeR. i think a car engine has an alternator by which it charges the battery . what do we need a further alternator ?

That automobile alternator runs of a belt, using only a fraction of the engine's power output. The alternator I mentioned is a huge thing - probably as big as the engine itself. (Think of a 50 HP motor). It goes in where the gearbox is currently.

please bear with me if my questions are amateurish.

I have asked (and said) dumber things elsewhere. ;-P

All said, for home use, you need "maintenance free". Unlike factories, or commercial establishment, where we can afford (in terms of time and effort, not just money) to hae a bit of down time once in a while, and probably, a bit noisy thing, residences require silence and "instant" on when power fails, right? Go in for a brand new genset.

@Gasolinejunkie, muneermk is probably right about heavy vehicles having a separate engine for running a/c. Those a/cs require more power, but more importantly, with a separate, smaller engine, a/c runs even when the main engine is switched off. Trucks carrying frozen items (mostly seafood) and those meant to haul reefer containers (containers meant to carry frozen items), have separate generator units for powering the container's freezing system. These are however far more compact than the a/c units in passenger vehicles.

Dont ask me why - I do not know.

[alpha1]

OP: Of course they are.
If you don't believe me then please check out the petrol generators of yesteryears from Birla-Yamaha etc

Anyway, turning to more arcane stuff, I visited one restaurant near my place.
The gentleman owner had propped up a small tractor in the courtyard.
We felt that it was just that - a prop.

Later after the dinner pleasantries, we had a small talk with the proprietor, and we came to know that the "tullu"-tractor, was indeed a gen-set. The diesel engine of the tractor mated to a dynamo, and transformer.

[tanwaramit]

Petrol driven engine to power electricity for home - Not a good option
LPG driven genset from Honda - Not available, as the workers on strike and factory is closed -- not sure for how long
Diesel based genset -- Good option
Kerosene based genset - To be started using Petrol - Another decent option if you can source kerosene
Diesel Car engine -- Quite a decent option. Now figure out the modifications needed to be done to use it

Do keep us posted whatever solution you choose.

muneemmk is right, some buses use CNG and they have an option of an additional engine to be fitted for AC as the pickup and speed with CNG for some of these vehicles is quite low, and with AC the bus may not pickup.

[Gasolinejunkie]

Originally Posted by BaCkSeAtDrIVeR

@Gasolinejunkie, muneermk is probably right about heavy vehicles having a separate engine for running a/c. Those a/cs require more power, but more importantly, with a separate, smaller engine, a/c runs even when the main engine is switched off. Trucks carrying frozen items (mostly seafood) and those meant to haul reefer containers (containers meant to carry frozen items), have separate generator units for powering the container's freezing system. These are however far more compact than the a/c units in passenger vehicles.

Ok, I’m not arguing. I just want to hear an account of someone who has seen it. Because I’ve spoken to heaps of veteran mechanics and engineers and they say they haven’t seen anything like it and the idea would be ludicrous. I know for a fact that Volvo B7R & B7RLe only have one engine. And regarding pick-up, the AC compressor relay switches off under hard acceleration.
Yes, I’m not talking about frozen container trucks. They have self contained roof mounted AC units with motor, compressor, condenser, & evaporator in one. Mainly because the containers get shunted from ship to truck or vice-versa and because of anti-idling laws in truck stops.

Originally Posted by BaCkSeAtDrIVeR

That automobile alternator runs of a belt, using only a fraction of the engine's power output. The alternator I mentioned is a huge thing - probably as big as the engine itself. (Think of a 50 HP motor). It goes in where the gearbox is currently.

Yeah, exactly. I know people who run fridges and random camping equipment from a 4WD batteries but again thats because you get nothing in the bush. To have a engine idling only to run an alternator is a waste of power.
@drkunaldas the 2.5lakh generator your talking about will be a LOT bigger than a Santro motor. The little Hyundai pump might produce a mere 10hp @ idle.

[sgiitk]

I am aware of someone who put a Lombardini petrol engine on an alternator. He later changed over to LPG. Had one problem - icing of the evaporator.

In principle it is possible to add a speed governor to a petrol engine and run it in with an alternator for power. The problems are

1. Petrol engines will not have much power at 1500rpm. Most alternators are 4 pole and need 1500rpm. So you have to put a small 2:1 reduction gearbox with the engine at 3000 rpm.

2. Enhance Engine Cooling: remember the car is running. So with a static engine all cooling has to be provided with no ram air cooling.

IN principle you can take the car alternator output and then put an Inverter Circuit on it. However, even the biggest is 100A, i.e. 1200VA, hardly worth the effort.

3. I did see some ads recently from the firm who have taken over Lombardini selling Petrol / CNG / LPG generators. With PNG it should be on to run a domestic power plant on this at reasonable cost, and far higher reliability than the diesel units.

[muneemmk]

Originally Posted by Gasolinejunkie

Ok, I’m not arguing. I just want to hear an account of someone who has seen it. Because I’ve spoken to heaps of veteran mechanics and engineers and they say they haven’t seen anything like it and the idea would be ludicrous. I know for a fact that Volvo B7R & B7RLe only have one engine. And regarding pick-up, the AC compressor relay switches off under hard acceleration.

I have seen one with an Isuzu Diesel Engine,It was a Leyland bus and on one side there was this engine which was running, I have even heard about tempo travelers with auxiliary engines,but all these are for A/C only and not for current generation.

[SamtheLeo]

I certainly sure that a tractor engine can be used as a generator as well as in tubewells to generate power. Theoritically all engines would be able to do so but here I belive that the difference is endurance & performance. All petro or typical diesel car engines are built for performace but for diesel gensets we dont need that kind of performance we only need that the engine can go on for long times at typical speed. So aligning these engines would not be cost effective & also would not have long life. However vice versa is possible when we see diesel gensets being deployed with gearbox in a local vehicle named as "Juggad" in northern India. Juggad is again not capable of high speed & pickup but certainly carry a truckload of wieght ot 50 persons at one go.

[silver_shadow]

if you are really serious, pick up an old diesel engine (from a totalled car) from the junk yard for a fraction of the price and use it for the project.

[anujmishra]

Some ten years ago people in our native did not buy Hero Honda MotorCycle fear of being stolen. Reason Hero Honda Engine (CD 100, and CD100 SS) were most suitable for gensets. Many Hero Honda theft cases reported and people were buying Rajdoot even they like Hero Honda.

So, there are people available in world who can make generator with any engine.

[dustom_99]

well i think ,basic question was,if santro's engine can be used as a generator or not.
theoretically -yes
practically - yes.
economically -yes (if u have the budget for the experiment)

almost all of us have expressed our emotions till this point,however noone came up with a technical jugad .it would be jugad alright but certainly a long lasting technically challenging one.

here is what i would suggest,i would try to be technical( as far as i can be).

santro engine- peak power rpm (i dont know) lets say its 5500rpm. u have the engine u can find that out.right
peak power- (i dont know) lets say 60 bhp. if its an old engine (well maintained) ,take a factor of 1-3% power drop every year (due to over sizing of cylinders,carbon deposits in valves and cylinder head. mind it this is generally taken for large diesel engines,now because large diesel engines have far more life than piddi petrol like a santro u might want to take an appropriate factor. trust your instincts and take a factor resonable enough.

ok lets say now your engine is in range of 50bhp.(minus yearly power loss)
50bhp= some 36kw i guess! heck of power for a genset (would run 14.5 AC considering 2500watt per ac),(or would light 360 bulbs 100watt each) simple enough maths..isnt it?
but simple math does not seems to apply here,or does it?
any altornator u buy from market would come with its rated rpm(according to number of poles) also altornator would not be 100% efficient.taking very good and high efficiency altornator (indian made) would be something around 84%. so it would be generating some 28.5kw of electricity at its peak efficiency.
however we cannot take for granted that a naturally aspirated petrol engine would be used at its peak power at constant rpm,that would pose serious efficiency issues as well as relibality issues.
so its your bet if u want to take a factor to bring down the engine to its rated load,which would be ideally about 70% of full load,if u dont care for life of the already old engine u can go with this simple calculation.and hey ,please do take care of mechanical power transfer losses(coupling and power transfer and all that crap that eats your money and turn it into heat and sound and vibrations.i dont know how much they would amount to,taking about 5% i guess)

ok, so now we have an altornator that would give about 26kw from a 36 kw engine.good enough.trust me,apart from really big gensets,very few would be able to bring out that input to output factor.

now just convert your rated load RPM of engine to your altornator RPM. you would get a reduction factor.let us suppost altornator rated rpm for 50HZ is 1400rpm.
if peak load RPM is 5500,rated load RPM would be something like 4800 or may be 4600. just take the rpm where engine gives about 75% of peak HP.
4800/1400=3.42.
now construct a fixed reduction gearbox,(just mate two gears with that ratio,mount them on shaft ,and fix the shaft end with bearings into iron plates.(usually car differential has ratios like that(3.2:1 to 4.5:1) u can use those gears.they would come with apporopriate bearings aswell..

couple the whole thing,mount the thing preferibly on wooden or cast iron base,to reduce vibrations.

start the new found nuclear reactor,(always install the standard radiator with fan according to engine)
measure electrical output frequency using standard multimeter,adjust throttle according to 50HZ. and you have made yourself some power for sure.

i dont know if it would be economical or not,and if it would be a long term solution or not,however if the reduction gearbox is made fully enclosed with proper mating and gear oil,i think genset should work find with regular service and retightning.
and hey if u generate surplus power u can always supply it to your neighbourhood in powercuts and charge them a lil higher that state board,that would be one way to recover money. however its against state board law to use there transmission line for such distribution .

just indulge man,even if u come up with half of all those kilowatts it would be a project u would remember for life my friend

keep posting!

[sgiitk]

I woul suggest simply use a governor for 3000rpm and put a two pole alternator on it!

[jeepster]

Originally Posted by ananthkamath

Somebody I know was using a contessa 1.8L petrol engine on LPG for the same purpose.

yes it is possible to run a petrol engine from bio-gas plant to generate electricity for agricultural use.
many people (read farmers) are using this method.