Community Forums

Latitude · 03-09-2009, 07:58 PM

So Paul

Does that mean the 10 and 12 run at Higher RPM all the time?? They dont have a low speed/demand???

Learn something New every Day!!

Rick

RVDude · 03-10-2009, 01:40 AM

Hate to be the consensus buster, but there is a partial error in the consensus.

According to the Onan operators manual for both the 10kw/12kw units (HDKCA, HDKCB), the section entitled "Exercising the Genset" specifically states run the genset at least 2 hours each month at 1/2 rated power if use is infrequent. It goes on to say - This drives off moisture, re-lubes the engine, replaces stale fuel and removes oxides from teh electrical contacts. The result is better starting, more reliable operation, and longer engine life.

Storing for more that 120 days w/o exercising requires a whole different proceedure including oil change, 12v discon, closing fuel supply, ensuring AGS is deactivated, and discon of 120v breaker.

The 10kw/12kw units run at a "constant" speed regardless of load. This is a function of the engine being a constant speed diesel where its power output matches load at a constant speed by increasing fuel supply (but not rpm) with increasing load. Just because it runs at constant speed does not mean you are properly exercising the alternator w/o loading it. So, at no load the fuel consumption is .11 gph, at 1/2 load it is .48gph and at full load it is 1.01gph(10kw) or 1.2gph(12kw).

Just want to provide the horses mouth Onan data to y'all.....

TXiceman · 03-10-2009, 06:09 AM

[quote=Jetsmania;478194]

Quote:

Originally Posted by TXiceman

Generally you should run the generator at 1/2 load

Hi! With 10 & 12KW Gensets, the amount of load on them does not matter. They are a one speed Genset that load has no bearing on how it runs, unless of course you overload it. The smaller Gensets, (I believe 7.5 and below) do need a load put on them. paul

As noted above, the generator set runs at a constant speed to produce the electricity with the proper frequency. It is either a 2 pole, 4 pole or a 6 pole (3600, 1800 or 1200 RPM) design depending on the operating speed to produce 60 Hz power. The ac current devices need a constant frequency power, thus there is a constant speed.

An inverter duty generator can operate ar a variable speed as it creates the frequency with the electronic circuits in the control circuit.

In order to heat the windings, you must put some load on the generator and at least 1/2 load is preferred. The little 1500 watt space heaters do a great job of loading the generator when you can run the A/C units.

becks · 03-10-2009, 10:40 AM

My feeling is to run any genny, any size, ever made, at least one hour under at least one half load each and evey month the MH is sitting idle. That along with required maitenence and you will have few problems with your Onan.

stubeje · 03-10-2009, 05:56 PM

I run mine about 30 minutes each month with the heat pump both on...I am in Illinois this winter...

Jetsmania · 03-11-2009, 09:15 AM

Hi! Sorry about the misinformation. The reps at the Onan booth are the ones who told me that. Thanks to RVDude for reading the book. I wish I had the guys card who told me, so we can set him straight. I was also told one hour was enough also. I will be firing everything up in the future for two hours. I think it is time to start reading some of these manuals.

Paul

j griff · 03-11-2009, 09:43 AM

Like others above, I run my generator under load for at least 30 minutes, usually closer to 1 hour every month. I do this while also driving the MH for about 30 miles and try to exercise every system in the MH (except winterized water system). I put out all slide outs and power awning, etc. This has been my practice for a number of years and I believe it pays dividends.

RVDude · 03-11-2009, 10:14 AM

Just wanted to re-iterate what the Onan manual says about this topic. Your preference may be entirely different but the manufacturers written recommendation (hearsay is always subject to error) should be your starting point.

According to the Onan operators manual for both the 10kw/12kw units (HDKCA, HDKCB), the section entitled "Exercising the Genset" specifically states run the genset at least 2 hours each month at 1/2 rated power if use is infrequent.

Jetsmania · 03-12-2009, 07:17 AM

Hi! I like the idea of using everything. I am also going to the 2 hour thing.

J Griff: WOW! THANKS for all the years of service to our Country!! Paul

LLonearth · 03-12-2009, 07:23 AM

Another good idea if you are not using the generator often is to put some gas treatment like Seafoam in the gas tank. That seems to help keep the carb clean. Gas formulations these days seem to evaporate even faster and can leave that "varnish" in the carb.

tmar10 · 03-12-2009, 08:43 AM

Ran my yesterday, both AC units running for around and hour.

FlyingDiver · 03-12-2009, 09:35 AM

Quote:

Originally Posted by LLonearth

Another good idea if you are not using the generator often is to put some gas treatment like Seafoam in the gas tank. That seems to help keep the carb clean. Gas formulations these days seem to evaporate even faster and can leave that "varnish" in the carb.

Diesel generator, no carb.

joe

JC2 · 03-13-2009, 12:23 AM

We frequently use our 7.5 Onan when traveling so it gets a pretty good workout throughout the season. When parked for the winter, I stabilize the gas, run the gennie at 1/2 load or so for 1-2 hrs, try to drive the MH 2-3 times during the about about an hr or so each time and use (3) cans of Seafoam in the spring after dewinterizing.

porscheracer · 03-13-2009, 08:39 PM

Neither of our motorhomes is parked for over a month at a time, so "extra" exercise is not necessary. However, on our 40' race car trailer, the 6500 gas Onan has to be exercised or the carb gums up - even with StaBil.