230V alternator for VP D3-190

There is probably a reason why this wont work but why can't you connect an inverter directly to the alternator rather than the batteries? I think most alternators are at least 120 ampres @ 12v so should easily power a fairly big inverter? If it works it's probably easier and cheaper than buying a 240v alternator....

So why wont this work?
 
I need 3.5kw continiously several hours (skuba tank compressor)
120Amps at 12V is only 1440W
I'd be better off with a 24V or 48V alternator, and an invertor,
I believe thats the basic priciple on which these 230V alternators work, but I am not sure
 
Double check the max RPM against your engines, these units look like constant rated Alternator and work at 1500RPM constant.
 
its not so difficult to make the installation so that normal cruising RPM (2800 rpm f.e.) equals the alternator RPM, (1500 or 3000) but what happens when you accidently, or need to put higher or lower trottle, so what happens with power, voltage and frequency when RPM is too high or too low ?
 
A car DC alternator gives out 12v + or - a couple regardless of revs so can't see whe an AC one should be any different? I would imagine 1500rpm is the minimum for full current but don't imagine more revs will make any difference?
 
with a cheapy type one such as the machinemart examples - if you vary from the specified revs, the frequency'll change for a start either up or down from 50Hz depending on what you do with your engine speed. Same alternators may also be poorly regulated at below their rated ( or some lower level ) output.

Sooo, you'd be better with an inverter type one, which is sortof similar to having a big alt + inverter ; these keep frequency constant regardless of engine revs & also regulate rather better ( so long as they are spinning fast enough to produce the power your compressor wants ). But, they cost a lot more.

Even finding one, is it feasible to get the necessary drive belts/pulleys on a D3?
 
Andy, Yes you're right, that was also my thought, an 48V DC alternator with an ivertor, I guess the VW works like this, but I don't know another supplier of such a system ?
The fixing + pulley's + belt on a D3 we can manage
 
well, you can either find a hugeish alternator ( 24V or more, minimum 4+KW) + buy an inverter & wire it all up with a suitable battery bank to manage the compressor motor startup current; or the likes of Fischer Panda do ( or used to ) make ready made 230V alternators that work that way ( pretty pricey too iirc )

Naturally, the first option means you can run the compressor w/o the D3 going, the second doesn't.


like this tho I thought they did a bigger one too
 
There is something called an Electolux travel power which seems to be what you are looking for. It seems to be the method for power on live aboard barges etc.

Can't find much info on cost or where to buy but seems to come in 3.5kw or 7kw versions.

Scroll down to the bottom of THIS page.

Also mentioned on page 2 HERE
 
Thank you Kevin, I am pretty sure this is the supplier of the Volkswagen Option, (have a close look at the electronic box etc...) hopefully cheaper then VW, will continue my search from your link, thanks again !
 
Thank you Andy,
yes indeed this is a second option, but for this solution I need an extra bank of battery's, space and weight becomes problematic or I need to change the complete electric system to 24V,
nevertheless many thanks for your time and advice !
 
actually the fischer link was for the wrong thing - I believe they did a 230V single-phase version, much like the Dometic one.

The guy that runs Ledgardbridge mentioned these on a canalboat forum. They have an optional regulator,not sure how they stop the frequency from changing & being US made are likely 60Hz.
 
Can't you do a PTO from the engine to a engine driven compressor?

Would be more efficient and save you having a high voltage EL compressor onboard (close to wet stuff), just connecting pipes up to where the tanks are being filled.
 
Alf, have been thinking about this, but then again I have the problem of the stable RPM, the compressor can probably run at lower RPM, but what happens when you turn up RPM above compressor max RPM. (filling tanks during cruising) Also I would need some mechanical gear that can be engaged or disengaged, and finally I would like the compressor to remain portable so that it can be used at other occasions aswell. IMO The electric power connection is the most conveniant.
 
I have found one

Just bring this up again as I have a Dometic Travelpower 3,5Kw with D3 mounting kit for sale,
it didn't work for my compressor,
this unit is still in perfect condition, it is only used for testing.

Does anybody know where I can place an add for selling this unit and show some more pictures and specs ? (in UK)

the "for sale" section on this forum only allows max 400£, it is for sale for 1750euro

travelpowergenerator.jpg
 
You could put it on Ebay. The for sale section of this forum allows links to Ebay sales in excess of £400.

Another option would be to put several pictures and a comprehensive description onto a web page, plenty of free space about if you need it. You could then place a listing on Ebay, linking to the web page and a link here to the Ebay listing. Having it's own web page removes any Ebay constraints about picture numbers, sizes and quality, as well as limitations with wordings and layouts.
 
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