How Do You Use Your Generator?

[Exile]

Originally Posted by rob67

Hi, on diesel generators its best to run at 75% load .I have spent 18 yrs working on generators for military use and we would run them 24hrs 7days a week. Anything less then that and you risk blow by on the rings causing oil to get into the cylinder.

I am very interested in your comment about blow by from generators being under utilized. I have what is probably a 28 year-old 8kw 3-cyl. Westerbeke that has always smoked a bit & used some oil since we bought the boat in 2007. It had 400 hrs. at that time, and now has about 1200 hours. The first mechanic we talked to suggested it was the valve guides/seals, whereas the second tech was dubious. I haven't tracked it very well, but I'd say it uses 1 litre/40 hrs. or so, and often times you can see & smell blue smoke. I want to say it improves the more we run it, but hard to quantify. If it's oil getting past the rings (vs. the seals), why is this attributable to lack of use? And why not the same scenario for propulsion engines that sit for long periods of time? We have never used a drop of oil in our Westerbeke 82B and it has a similar history.

Thanks,
Dan

[bobconnie]

Sailing where we do, ( Gulf of Mexico and below) we run our genset as much as needed for air Conditioning, and the water maker and big freezer aboard. Our Old Old 4 cyl Italian engine turning a 5.5 KW genny burns less then .400 of a gal of diesel an hour. As we can carry a little over 500 gals of diesel, we don't worry about running low. Once we get a few miles offshore from Louisiana it really cools some and we mostly only need the gen set for AC at anchor to sleep!

[FlyingCloud1937]

I have a simple black box, it is comprised of a watt hr meter, and an hr meter. I hook it up to the gen out, and the op switch.

After a month installed on customer boat, on average. I find that the watt hrs produced, against time, and rated Generator. That the system is running about 20-35% of load capacity.

Under-running a gen causes wet stacking, which fouls the bores, rings, and valve seats, and worst of all carbons up the injector tips. This leads to fuel fouled lube oil.

If your are going to run an A/C gen run it in batch mode, use an inverter for incidental loads.

Now back to the OP....NEVER RUN IT WITH OUT SEAWATER...don't forget to open the seacok...hhehe

Lloyd

Originally Posted by Originally Posted by [B

rob67[/B]]
Hi, on diesel generators its best to run at 75% load .I have spent 18 yrs working on generators for military use and we would run them 24hrs 7days a week. Anything less then that and you risk blow by on the rings causing oil to get into the cylinder.

Originally Posted by Exile

I am very interested in your comment about blow by from generators being under utilized. I have what is probably a 28 year-old 8kw 3-cyl. Westerbeke that has always smoked a bit & used some oil since we bought the boat in 2007. It had 400 hrs. at that time, and now has about 1200 hours. The first mechanic we talked to suggested it was the valve guides/seals, whereas the second tech was dubious. I haven't tracked it very well, but I'd say it uses 1 litre/40 hrs. or so, and often times you can see & smell blue smoke. I want to say it improves the more we run it, but hard to quantify. If it's oil getting past the rings (vs. the seals), why is this attributable to lack of use? And why not the same scenario for propulsion engines that sit for long periods of time? We have never used a drop of oil in our Westerbeke 82B and it has a similar history.

Thanks,
Dan

[FlyingCloud1937]

No...

You can't measure the load of a generator by Hz, or voltage.

You can only measure by watt hrs against time.

A droopy gov can effect Hz, and volts. A wanky regulator will cause erratic voltage...neither of which measure either against time.

Lloyd

Originally Posted by Exile

As for your question about how to determine the load on your generator, I've always wondered the same thing and just asked in the previous post whether this might be determined (albeit imprecisely) via the Hertz meter.

As for how the batteries get charged, the generator produces 110v (probably 240v on Dockhead's) of AC power which supplies a battery charger which also runs on 110v. This charges the batteries and other AC appliances just like being plugged into shore power. Not sure about others, but my genset also has its own 50A alternator which, via its regulator/rectifier, supplies DC power directly to its own start battery.

As to whether the engine alternator or the battery charger would charge your batteries faster, the simple answer depends on the output of each one. The better question might be which one can do it more efficiently. In my case and I would think for most, the genset will burn much less fuel/hour than a propulsion engine and so is the obvious choice when under sail or at anchor/mooring, especially if there are benefits to running other AC appliances (e.g. refrig, watermaker, a/c, heater, stove/oven) while you are also charging your batteries.

Dan

[JTSmith]

Seems like this might be a good place to ask this question. Hope I'm not drifting. I've chartered several boats in the past with gensets and so am familiar. But my "new" Hunter 40 has a SeaPower 5kw engine driven generator. No familiarity with this. What's the skinny on this thing? Advantages? Disadvantages? How to use? Any input would be most appreciated!


Sent from my iPad using Cruisers Sailing Forum

[GordMay]

"Sea Power" (a DC alternator mounted on your propulsion engine) was/is manufactured by Mobile Electric Power Solution, Inc. (MEPS).
CEO Bill Chambers is very helpful.

Mobile Electric Power Solutions, Inc. (MEPS)
2714 West Kingsley Road, Suite A-2, Garland, TX 75041
PO Box 550248 Dallas, TX 75355-0248
Telephone: +1-972-864-1015
Fax: +1-972-271-0635
Web ➥ http://www.meps.com/New_Site/Documen...ochure-kVA.pdf

[JTSmith]

Originally Posted by GordMay

"Sea Power" (a DC alternator mounted on your propulsion engine) was/is manufactured by Mobile Electric Power Solution, Inc. (MEPS).
CEO Bill Chambers is very helpful.

Mobile Electric Power Solutions, Inc. (MEPS)
2714 West Kingsley Road, Suite A-2, Garland, TX 75041
PO Box 550248 Dallas, TX 75355-0248
Telephone: +1-972-864-1015
Fax: +1-972-271-0635
Web ➥ http://www.meps.com/New_Site/Documen...ochure-kVA.pdf

Thanks, Gord. Do you just run the engine and the SeaPower at anchor to provide power? Why not a separate genset?


Sent from my iPad using Cruisers Sailing Forum

[ranger58sb]

Originally Posted by JTSmith

Thanks, Gord. Do you just run the engine and the SeaPower at anchor to provide power? Why not a separate genset?

Can't tell, about your specific installation, but in some cases a separate genset may be not much smaller (if at all) than your auxiliary.

Our genset's engine is approx. the same displacement/horsepower many of you have as an auxiliary propulsion engine. (Yanmar 3TNE74, max rating 19.1 kW (26.0 PS) or 25.6 HP at 3600 RPMs, continuous rating 17.4 kW (23.6 PS) or 23.3HP at 3600 RPMs. Although it actually only runs at 1800 RPMs in the genset implementation.)

Maybe no real savings (and significant additional costs) having a separate unit.

-Chris

[colemj]

You can measure the load on a generator just by looking at how many AC amps the loads are using. A 6KW 120V generator is rated to produce 50A, so 75% of that is 37A.

If you don't have an AC ammeter on the panel, just calculate the amp load from each appliance.

Some estimates: a 16Kbtu AC unit will draw ~13A, a 100A battery charger will draw ~20A, a 1500W water heater will draw ~12A, a 30gph AC watermaker will draw ~10A.

Mark

[a64pilot]

Really should have an amp meter, they are simple and cheap, else how do you know how hard you are running the thing? I have to watch my amp meter even when on shore power, or I can overload the panel / cable

[Exile]

Originally Posted by colemj

You can measure the load on a generator just by looking at how many AC amps the loads are using. A 6KW 120V generator is rated to produce 50A, so 75% of that is 37A.

If you don't have an AC ammeter on the panel, just calculate the amp load from each appliance.

Some estimates: a 16Kbtu AC unit will draw ~13A, a 100A battery charger will draw ~20A, a 1500W water heater will draw ~12A, a 30gph AC watermaker will draw ~10A.

Mark

So just like with 12v applications, you can generally determine your generator's amperage output by dividing its rated wattage by the voltage. In your example that's 6,000 watts divided by 120 volts = 50 amps. On mine & maybe others, however, my AC system is divided into two, 30A circuits. When I account for the much higher start-up amperage of my two a/c units, for example, I am limited to how many appliances I can safely run on each circuit. Not sure this gets me to the desired 75%, but I'll investigate.

Lloyd -- thanks for sharing the info about measuring loads, etc., along with proper running techniques. I suspect that the little amount of use my generator has had over the years is contributing to my oil consumption, but I'm not sure what the remedy is short of a rebuild which wouldn't be worth it at this point.

Dan

[FlyingCloud1937]

Originally Posted by Exile

Lloyd -- thanks for sharing the info about measuring loads, etc., along with proper running techniques. I suspect that the little amount of use my generator has had over the years is contributing to my oil consumption, but I'm not sure what the remedy is short of a rebuild which wouldn't be worth it at this point.

Dan

Things that make diesel generators smokey...

Dirty oil

Wet stacking/running under light load

Not adjusting the valves

Old fuel

Bad injectors


Things to do to try and clear up the smoke...

Fresh lube oil

Check and adjust valves

Check the timing on the HP pump

Run the generator at max load for an hour


If that doesn't help...

Warm up the gen, with no load slowly tip a pint of Marvelous Mystery Oil mixed with a pint of Automatic Trans Fluid down the intake, shut down afterwards.

Pull the injectors, have em checked and rebuilt if required

Re-install the injectors, warm it up under light load, then increase the load to max for an hour.

Change the oil

If it still is smokey then it may be time to pull the head.

Lloyd

[Cadence]

Originally Posted by Exile

I am very interested in your comment about blow by from generators being under utilized. I have what is probably a 28 year-old 8kw 3-cyl. Westerbeke that has always smoked a bit & used some oil since we bought the boat in 2007. It had 400 hrs. at that time, and now has about 1200 hours. The first mechanic we talked to suggested it was the valve guides/seals, whereas the second tech was dubious. I haven't tracked it very well, but I'd say it uses 1 litre/40 hrs. or so, and often times you can see & smell blue smoke. I want to say it improves the more we run it, but hard to quantify. If it's oil getting past the rings (vs. the seals), why is this attributable to lack of use? And why not the same scenario for propulsion engines that sit for long periods of time? We have never used a drop of oil in our Westerbeke 82B and it has a similar history.

Thanks,
Dan

Someone may have thought about the main and not the gen. prior to lay up. Rebuild it or if it serves you keep oil on hand. When it get to putting your slicker over the air intake, to stop it, rebuild it.

[Exile]

Thanks for all the suggestions. The only ones I cannot safely rule out are FI timing & running too light of a load. I thought there were only two ways for oil to get into the combustion chamber, namely up past the rings or down past the seals. Since I thought the seals were made out of some sort of rubberized material, I figured they would be a good candidate for drying out/shrinkage from non-use. In any event, I will first try to run as full a load as possible for awhile the next time I'm onboard and see if that helps. If not, I'll move on to some of the other suggestions. Thanks again!

[FlyingCloud1937]

A wet stacked engine, glazes the bores which allows oil past the rings. The heated oil polymerizes in the bores cross hatching.
A wet stacked engine, carbons up the ring lands which allows oil past the rings.

Ruining Hard can help burn the carbon out of both places, it can even help de-glaze the bores somewhat.

The MM/ATF trick can/will internally desolve the carbon, and even help de-glaze the polymerized bores.

If it were the valve guides, it would stop smoking after warm up typically.

Lloyd

Originally Posted by Exile

Thanks for all the suggestions. The only ones I cannot safely rule out are FI timing & running too light of a load. I thought there were only two ways for oil to get into the combustion chamber, namely up past the rings or down past the seals. Since I thought the seals were made out of some sort of rubberized material, I figured they would be a good candidate for drying out/shrinkage from non-use. In any event, I will first try to run as full a load as possible for awhile the next time I'm onboard and see if that helps. If not, I'll move on to some of the other suggestions. Thanks again!