Why running on low load is hurting your finances and the Environment
Do you run your generator on less than 30% load of its rated output? If so, you could be wasting money, possibly causing damage to the engine and omitting more emissions than is necessary.
Running on light loads will often cause a far higher than normal consummation of lubricating oil and fuel, than it should be, increasing your emission output and environmental impact.
Furthermore it can result in 'Wet Stacking', which indicates the presence of unburnt fuel or carbon in the exhaust system. This can result in oil starting to drip from junction glands, exhaust manifolds or even flanged joints. This not only causes engine faults, but also shortens engine life.
Your generators will likely be providing essential power services, these problems hurt the reliability and effect their ability to support you in the case of a power outage.
Why does running on light load create these issues?
To operate at maximum efficiency, a combustion engine must have the exactly correct air-to-fuel ratio and to be able to sustain its designed operational temperature to ensure all fuel is burnt.
When a generator runs on light loads, it will not be able to get hot enough to attain the correct operating temperature, thus low loads = low temperatures.
When this happens, it can result in some of the unburnt fuel going out the exhaust having been unburnt, and so appearing wet, hence the risk of 'Wet Stacking'
Furthermore, insufficient exhaust temperatures cause leakage from turbo, seals and expansion joints. This results in oil delivered together with the air into the engine air manifolds. As well as build-up of carbon in the exhaust side of the engine, having negative effects on engine performance and efficiency.
Prevent problems rather than fix problems!
An obvious prevention is simply to avoid running on light load as much as possible. Short periods, 10 minutes for example, may be unavoidable, but for short periods of time the issues are lowered.
Once a year, make sure the set has ran on full load - Prime Rating - for around 3 to 5 hours. Doing this will help the set by burning off the build-up of carbon within the engine and exhaust system. If this can't be done by the local power requirements, a mobile load bank can be used to make sure that the max load is obtained. However if this issue has been ignored for too long, the engine will need a major overhaul for all carbon build-ups to be removed.
This can be performed during a generator test. In fact, a proper test should include a load bank able to take the generator to max load. A test without load is no real test at all, all what is proved is that it will start.
Correctly taking your generator to 100% for 3 to 5 hours is difficult for general companies, and it's certainly not practical to perform your own tests.
This is why Ingrams invested in our own mobile load banks. We are able to expertly test your sets, correctly to their requirements.