Generator off the Main Engine Possible?

[oldcal46skipper]

Originally Posted by Honey Ryder

Does anybody have a generator which runs off their main large engine that works sufficiently well so that electronic equipment can be powered by AC?

My current set-up is a 130hp normally aspirated diesel to drive the prop shaft, and a separate small diesel powered generator to produce AC.

Is it possible to hook up and run a generator head off the 130hp and get rid of the small engined generator? And does it make sense?

I've read that generators need to be run at a constant 3600rpm to maintain voltage and amperage...which means that there is a problem if the rpm on the large engine is not held constant...is there a solution?

Replying to the OP's ?:
I have belt driven a 8KW 3600RPM generator off the "front" end of my Perkins 4.236 for 26 years. The 4.236 was designed as an industrial type engine that could deliver the same load off either end, so I built a frame to hold the generator, (my boat has a Vee drive, so the engine sets backward, i.e. the gear is attached to the aft end of the engine, which is pointed toward the bow of my boat). I had had the boat several years so I knew my most efficient motoring speed/RPM's was 6.2 knots at 1,550 RPM = 1.1 gallon per hour. So, I attached pulleys twin belt of the proper ratio to drive the generator at 3,600 RPM's when I was motoring at 1,550 RPM's . I set exact RPM's using a AC voltmeter @ 117 volts and a hertzmeter at 60 hz.

Theoretically, in smooth seas, clean boat bottom, my Cal 46 only requires 18HP to maintain 6.2 knots, so the extra load on the engine is negligable. Whenever we are motoring or motor sailing, we have the generator working and usually running our 120 volt AC, 20 GPH RO watermaker. When we reached our anchorage, we had a full 200 gallons of pure water and no indication of additional fuel usage. I have a 50 gallon day tank in the engine room with a marked sight gauge, so I closely monitor fuel consumption. I have an additional 350 gallons in amidships tanks. Yes, I am a motorsailer since there are places where the wind does not blow.

This simple system has worked well for me, 26 years, 3,600 engine hours, nine years full time cruising. It was great!

Anyone desiring more technical info, PM.

Keep It Simple

Tom

[Scott Berg]

I have an almost identical system using an 1800rpm10k Lima off my Lehman 135 with four drive belts. Was original with the boat in 1976 and works perfectly... Hertz meter at the helm was standard and we find its great for motor sailing... 1650 engine rpm provides 7kts and 240v AC power. Doing it again I'd probably favor for a multi alternator/inverter based design if I could afford it but this works very well

Scott

[Txman65]

Interesting thread! I have a 6.5 kW AutoGen 220/60hz ac generator mounted off of one of my Cat3208's on my 44Gulfstar MkII. The variable speed freq controller went out, but generator tested okay.

Is anyone familiar with these systems, or where I should go to get a new Freq Controller?

[Irish rambler]

Hi Honey Rider, as you know, you now you get plenty of opinions on here. I see you are moored in London and will probably cruise to Europe at some time in the future. Dockhead is perfectly correct but if I may add a bit more, buy either a Bosch or Valeo alternator as replacement parts for Leece Neville are as rare as rocking horse manure in Europe. I would recommend a 'soft start' Inverter of your preferred output and you can get one shipped from China, good quality and cheap, Google DHGate.com. As for you main engine battery charging, I would speak to Adverc.co.uk up there in cold Brummagem, ask to speak to Brian,he's a mine of info, if you wish to purchase from him tell him you were speaking to Geoff on board 'Sanity' and you will get a 10% discount.
Good Luck

[goboatingnow]

Originally Posted by Irish rambler

Hi Honey Rider, as you know, you now you get plenty of opinions on here. I see you are moored in London and will probably cruise to Europe at some time in the future. Dockhead is perfectly correct but if I may add a bit more, buy either a Bosch or Valeo alternator as replacement parts for Leece Neville are as rare as rocking horse manure in Europe. I would recommend a 'soft start' Inverter of your preferred output and you can get one shipped from China, good quality and cheap, Google DHGate.com. As for you main engine battery charging, I would speak to Adverc.co.uk up there in cold Brummagem, ask to speak to Brian,he's a mine of info, if you wish to purchase from him tell him you were speaking to Geoff on board 'Sanity' and you will get a 10% discount.
Good Luck

That's cause there known as Prestolite in Europe, they have a manufacturing plant in the UK.

Dave

[Irish rambler]

Yes Dave you are correct, Leece Neville are known as Prestolite. in the UK & Europe. Unfortunately the problem in Europe is still the same with spare parts very difficult to source. Some hire boat company's had them fitted as OE and are phasing them out for just that reason.