Silent Generators - conclusions?

Martyn

I use a hired one of these and it is very quiet we used it at Billing to run

Peter

Martyn Hi,

would you consider using your car as a generator's motor and just adding to it a big inverter?

That is what I did with my 1993 Discovery 200Tdi and a 1700 W inverter (sine wave with 3000 instant peak limit)

Works very nicely up to now. I bought the inverter directly from Taiwan (it was a 10 units group purchase along with some friends from Cyprus) The inverter is a bit bulky but at 1700 W it is expected for it to be this way.

Main reason for buying it was to be able to provide 220 V, 50 Hz electrical power to my house in case of a blackout but it is also handy for power tools etc driven by the car.

Take care Pantelis

Honda's are by a long way the best, and the EU series are inverter generated mains. When the load is low, the generator runs slower. I have 3 Honda generators, from 1.5Kva to 5.5Kva and they are all magic!

I ended up with a Liyuan LYF950 (rated output: 650 watts, plus ~140 watts DC) and I'm quite happy, particularly for the price (under a ton including delivery). My only reservation is that it's rather smokey under load, but that may be down to me bing a bit slap-dash with the

However, it's rated at a good 10dB louder than this. You can hold a comfortable conversation while standing next to it, but "quiet" is stretching the definition a bit.

If you went this route, you have to remember that the load would have to be supplied primarily by the alternator - unless you set up an extra battery, and even then, it would need to be a pretty big battery to run any significant load for very long. JD

I already do this, but the 4.6L V8 with large bore stainless steel sports exhaust simply isn't 'quiet' enough ;-)

I want to be able to run my video projector at outdoor events in relative 'silence' - mainly so I don't end up annoying other campers, or having to wind the PA up to cover the sound of the generator.

Forgot to mention that the Discovery is a Camel Trophy one fitted with bigger alternator and twin batteries setup.

Should have said so in the first place but I am sure Mother knows my cars after so many years in the same newsgroup.

Take care Pantelis

Have you either a EU10i or an EU20i?

I'm tempted to go for the latter, the dry weight difference between the two is 8Kg but the 20i has twice the maximum power...

I reckon 13Kg is easily luggable, 21Kg a bit of a strain. They both have the same sound level though... Urgh... decisions...

In article , Mother writes

Radical thought: if yours is a 'modern' type of video projector, it's LCD, probably with a 24V halogen lamp. If so, it ought to be possible to modify it to run on DC directly - I'd guess it needs +5V, possibly +12V, and +24V (at decent current - say 10-15A).

I've done lots of outdoor PA using a batery-powered mixer and a car 'booster amp' as the power amp.I usually get round the requirement for 4 or 2 ohm loads and heavy cable by using 100V line matching transformers. It's not the highest of fi, but it's not all that bad.

Now, if you're originating the pictures from a laptop's DVD, you have the basis for a cool system...

Regards,

Simonm.

In article , Mother writes

Go and listen to one working under load before you decide. If it's annoyingly loud close up, put the palm off your hand close to the exhaust to see if there's a noticeable air movement. If there is it'll be difficult to silence further. Also the lower notes of the noise are harder to suppress than the HF. The latter can be radically reduced by a 'tent' of hardboard faced with Rockwool (or fibreglass). Obviously, you still need plenty of airflow.

Regards,

Simonm.

On this point, I have a couple of other generators which I've often thought are simply too loud due to the inefficient exhaust. Is it possible to add an extra silencer on an exhaust extension to frame mounted generators I wonder?

^^^ Scary typo!

Regards,

Simonm.

Mother"

Kin eck - another engine to go play with!

I had a quick look last night and it actually seems pretty simple. I'm going to play with a motocycle exhaust, cut down (free flow) first, to see if this throws the balance out too much. I did fire it up (I always fire generators up once a month or so anyway) with my 'how loud is this really then?' head on - and it's loud :-(

We have a db meter here somewhere - which I may have to dig out!

On or around Wed, 27 Aug 2003 17:34:35 +0100, Mother enlightened us thusly:

suck it and see...

try attaching a small car silencer, ferexample. Not exactly a generator, but a similar problem, we run a vacuum pump for a milking machine, these tend to be noisy. patched together a few old bits of car exhaust pipe and silencers, which made it a lot quieter and had the additional benefit of taking the noise out through the wall... but the noise from the end of the pipe is much less than without the additional silencers. depending on what frequency of noise is prevalent, you wither want a large or a small box ex-car-exhaust - experience teaches that the large box removes the high frequencies, and the small box removes the low frequencies.

No such thing as a silent generator, apart from solar panels!

They all make a lot of noise, some like the new Hondas make less noise.

Reg. (Owner of two Hondas.)

For the latter, put the genny in a box, internally faced with Rockwool (possibly backed with hardboard for low cost). Air in and exhaust out of the box needs to travel round some sort of labyrinth, but doesn't need any appreciable air resistance.

I used to have a really good ASCI art programme, but I've mislaid it (you can tell). All internal faces covered in rockwool. Doesn't need a floor, but probably around 3-6" clearance all round the genny frame. The idea is to arrange it so that the exhaust vents down the "out" pipe.

It'll get a bit warm in there, so you might need to augment the 'in' side with a fan. Rockwool is excellent at absorbing HF, and fireproof too (although hardboard isn't). If done carefully, I'd expect around

Regards,

Simonm.

This is probably feasible in a cold climate, but cooling of both the alternator and engine are fairly marginal in hot weather, without the box, and you will need to ensure that it is set up so that air cannot be recirculated inside the enclosure. The fan is a good idea, and won't take a lot of power. Also, the generator set needs to be on rubber mounts to avoid transferring vibration to the outer case. JD

In article , JD writes

Fair comments, both. I was assuming central/northern England, and I can well imagine problems in Au. I'd arrange it so that exhaust and inlet were on opposite sides for a start, and it's quite possible to baffle it in the middle, so that air/exhaust can't recirculate.

My ASCII art doesn't really do justice to what I had in mind, but Rockwool does make a very good job of this. I wouldn't contemplate running one of those small gennys other than on the ground. though

Regards,

Simonm.