Generator Low Load
Generator Low Load
(OP)
Dear forum members;
Our electrical generator starts consume oil rapidly (Oil level decrease therefore daily oil top-up is needed!).
The generator supplier claims that the power consumption (measured 110 amp) is less than the generator rating (250 KVA)!
My question is:
Is this the possible reason for the unusual oil consumption? Is there something like MINIMUM power consumption requirements for a given electrical genrator?
Your feedback and help are highly appriciated.
Thank you
Our electrical generator starts consume oil rapidly (Oil level decrease therefore daily oil top-up is needed!).
The generator supplier claims that the power consumption (measured 110 amp) is less than the generator rating (250 KVA)!
My question is:
Is this the possible reason for the unusual oil consumption? Is there something like MINIMUM power consumption requirements for a given electrical genrator?
Your feedback and help are highly appriciated.
Thank you





RE: Generator Low Load
Waross and Catserveng, among others, are the experts on such matters. They'll be in soon.
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: Generator Low Load
RE: Generator Low Load
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Generator Low Load
RE: Generator Low Load
RE: Generator Low Load
http://www.powerlite.com.au/default.asp?id=30
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(2B)+(2B)' ?
RE: Generator Low Load
For a car engine - does the same apply? I will tell the sheriff next time I'm caught for speeding "I have to load the engine to avoid glazing". Wonder if that helps?
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: Generator Low Load
* Thank you for your feedback and please accept my apology for my poor knowledge in this feild.
* Below are some information which may be helpful to understand the existing situation:
- This is a Desiel Engine Electrical generator, 3 phase, 415 volt, 50 Hz and is connected to a transformer that reduce the voltage to 350 volt and 60 Hz to power a soil washing plant.
- The maximum output is 250 Amps.
- The average operation hours of the generator is 16 hours/ day. Total operation hours of the engine is 1,808 hours (268 Starts)
- The generator is working in hard climatic conditions, very dusty & hot (>45 oC)
- The total kW of the plant is 195 kW
* I am not comfortable at all with the supplier feedback about low load. We are topping up 5 liters/ day oil (BP C3 50 Vanellus)
RE: Generator Low Load
The numbers don't seem to add up though, 195kW is probably about flat out for a 250kVA set in those sorts of conditions, which doesn't really match up to a maximum of 250A. Nor does a transformer have the ability to change frequency, and the change in voltage would give a different perspective on what the actual maximum current is.
Whilst we're discussing low loading, its also possible to overload a set, and somewhat surprisingly, running it at 100% for long periods of time can also be detrimental.
Either way, with 5L a day of oil consumption, your generator is sounding a bit sad. If its really low loading, waross and catserveng (and others) may be able to comment on loading up the set to alleviate the issue, but I suspect we'll need more numbers to go on first. I've had no experience with engine recovery, though I've seen a few smaller sets run at (around) 20% nameplate rating without too many issues (subject to certain conditions of course).
RE: Generator Low Load
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(2B)+(2B)' ?
RE: Generator Low Load
RE: Generator Low Load
The compression ring or fire ring of a diesel engine is designed so that the pressure of combustion acts on the ring to increase the force on the cylinder wall. It is rare but it happens from time to time that the rings of a new engine do not seat or seal properly. Running with a substantial load forces the rings to seat and they will eventually seal under light loads also.
I have cured one set by load banking for several days. Another set cured itself by pumping out all its oil in a few hours and shutting down on low oil pressure. Suppliers have expressed concern a few times when standby sets were over-sized for the normal load.
Another set about the same size as your was load banked for about a week at the insistence of the supplier. The full capacity was needed for motor starting, but normal running load varied from 10% to 25% of the set rating.
At 1800 hours the cylinders may be glazed and it may be too late to correct the condition by load banking.
Has the set been run at less than 110 Amps for a significant time?
Another possibility is a faulty air cleaning system. If your air intake system has a leak that has allowed dirty air to enter the engine the accelerated wear would give the symptoms that you describe.
With your loading and the hours on the set, wear due to dirt ingestion may be more probable than glazing.
Compare the cost of repairs to the cost of a new or rebuilt replacement engine. When you have the numbers in hand, you may consider an old school remedy. I have never done this but I have heard of it from several sources. With the engine running at speed, slowly add about one teaspoon of Bon_Ami (pumice powder) to the air intake. You may try this on two or three consecutive days. This will often break the cylinder glaze but will not help if the problem is excessive wear.
How long have you had this problem?
Bill
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"Why not the best?"
Jimmy Carter
RE: Generator Low Load
Maybe some more details from your end could help you get more specific answers.
How long has the oil consumption been excessive?
What is the rated BSOC (Brake Specific Oil Consumption) of your engine? Usually is given in grams per brake horsepower or kw hours.
Is this a natural aspirated or turbocharged engine?
You state you're running in a "dusty" environment, do you have heavy duty air filters with a precleaner?
Can you provide make, model and year of the engine?
Have you performed any lube oil analysis? I would be interested to see if there are elevated levels of iron, chrome and silicon.
Extended periods of light load operation can be a contributor, but for the size unit you're talking about the amount of consumption in about 16 run hours seems really high. I would suspect based on what's been provided so far that you may have ingested dirt into the engine and "dusted it".
Older engines with rectangular ring packs and low average cylinder pressures were more tolerant of low load operation for long periods of time, newer engines optimized for low fuel consumption and to meet current exhaust emissions regulations are much less tolerant, and are more prone to problems with slobber, wet stacking and excessive oil consumption.
Hope that helps, Mike L.