Hp gas compressor, diving air

[MapisM]

Just in case anyone would be interested in doing some math, according to the first owner of my boat, the MCH6 was able to trip a 6.5kW Onan, unless totally unloaded at the time when the compressor was switched on.
And while I have no idea about the breaker characteristics of the genset, I must say that I never had any problem with it since I bought the boat.
It never missed a beat even when used with 2 a/c compressors, oven, boiler, washing machine, etc.

PS: never used a VFD, though. I agree that more than likely it would have cured the problem.

 

[jfm]

Just in case anyone would be interested in doing some math, according to the first owner of my boat, the MCH6 was able to trip a 6.5kW Onan, unless totally unloaded at the time when the compressor was switched on.
And while I have no idea about the breaker characteristics of the genset, I must say that I never had any problem with it since I bought the boat.
It never missed a beat even when used with 2 a/c compressors, oven, boiler, washing machine, etc.

PS: never used a VFD, though. I agree that more than likely it would have cured the problem.

That all sounds sensible to me i. I think coltri are kidding their customers when they claim a 4kva genset is ok for this compressor. Ho hum, and hopefully potential MCH6 customers can find the correct answer on this forum LOL

 

[ebbanflo]

Just a thought, I don't know if it helps (or it is something you would want to do !) but back in my motorsport days, my service van was equipped with a generator and compressor. The genny couldn't fire up the compressor unless we opened the valves - and then close them after 10 seconds or so. I admit this is not ideal if your compressor is in a remote location.

 

[paul.norton]

A compressor which I have in my workshop, starts with the pump outlet de-pressurised.

The accumulator has a non-return valve which is supplied from the pump. When the pressure reaches that required, the pressure switch stops the motor and opens a small valve which de-pressurises the pipe supplying the non-return valve. Hence, much lower starting current.

Paul

 

[Robg71]

I would be suprised if any modern compressor came without offload starting.

Im trying to work out how much current all this stuff pull. Looking at the victron quattro, it will more than make upany shortfall in startup current.
Maybe i should have studied electrics better

 

[Robg71]

Had a look at the Bauer range. The oceanus may be a very good compromise between too small and too big. Come in between 44 and 61kg depending on spec. I assume 44 is electric, and 61 is the petrol powered version.
Also is a healthy 5cfm, and should handle 300 bar better than some of its smaller siblings.
A three phase version is offered, so bolting a vfd to the front to take care of phase should be a doddle...

 

[ARE]

Now you mention that Nick I remeber seeing it a while ago. I'm a bit baffled by the numbers and do not see how a 4kva genset (nominally a bit less than 20 amps) is going to deal with 42amps, unless Coltri is relying on the genset having a very slow breaker

That is exactly what they do, When we design a generator we normally work on 2 times (for 2sec) full load current for motorstarting for this very reason, If you have a larger genset with PMG option you can normally sec 3 times, but that is dependant on the type of load.

Generator mounted circuit breakers are specced to trip around 400% overload for 2-3 seconds to allow for this motor starting current required.

but having said this, I would say it would be touch n go if a 4kW genset would start a Coltri MCH 6.

Anthony.

 

[BartW]

Had a look at the Bauer range. The oceanus may be a very good compromise between too small and too big. Come in between 44 and 61kg depending on spec. I assume 44 is electric, and 61 is the petrol powered version.
Also is a healthy 5cfm, and should handle 300 bar better than some of its smaller siblings.
A three phase version is offered, so bolting a vfd to the front to take care of phase should be a doddle...

OK Rob,
The bauer Oceanus,
thats what I have chosen some 5,6 year ago,
the best package on the market at that time,
size, weight, and capacity 140l/min, (and 300 bar option)
BUT ! it has a 4Kw eleictric motor, i have mono phase, but 3 phase available aswell.

the main reason I choose for that unit was the ability to run in a heeling angle on a boat,
they have a special oil lubrication system of the compressor

long ago I spend a lot of time, trying to run this compressor on the (28ft) boat engines(s)
and got it eventually working on 2 x 3KW Victron Multiplus and the two Volvo D3's at 2000 RPM,
But because of the hasselfull installation, I finally replaced that electric engine with a Honda petrol engine,
(succesfully used ao on our dive trips to Cornwall and Schotland)

now this compressor is in Blue angel, back with the electric motor, perfectly runs on my mono phase 16Kw genny's
last winter I bought a second unity (exactly the same)
for backupt, and or to be able to have shorter filling times between dives
average filling of a 15l tank (never completely empty) is 20..25 minutes,
so sometimes we have had filling on BA for almost 3 hours,
considering the noise and someone standby for the tank changings, it made sense to buy a second unit.

we have found a good spot for both these compressors in BA's ER, left and right on top of the extra wing fuel tanks, just in front of air inlet louvres.
you can see yourselves during the FDC

what are your actual plans with the compresor,
use on a boat ? which one ?

 

[Robg71]

Thanks very much for that Bart
You have also hit on the equipment i was looking at to drive it. The victron inverters. I am looking at the quattros though. So compressor choice is good then.
Im currently looking at current load on a fifty footer for electrics, and these are going to run the 240ac, plus a generator.