This site uses cookies to deliver a better experience.

Find out more

Accept & Close


The dangers of running on a light load

If an engine is operated on a load of less than around 30% of its rated output, you could waste money and cause damage. This usually means the engine will consume much more lubricating oil than normal. Look out for an unsightly drip from the exhaust manifold, junction glands or flanged joints.

Here are the reasons why these problems occur:
1. Turbocharger oil seals don’t seal effectively on a light load. This means oil is delivered together with the air into the engine air manifolds.
2. The cylinder temperatures are too low to ensure that all the fuel delivered is burned.

Here’s how you can help prevent these problems:
1. As much as possible, avoid running on a light load. If you carry out weekly exercising with no load, keep the running period down to around 10 minutes, or until the battery charging rate returns to normal.
2. Every year, run the engine or generator set on full load (continuous rating) for four hours. This burns off the build-up of carbon in the engine and exhaust system.
3. You may need to use an ‘artificial load’. The load should be built up gradually from zero to full load over the four-hour run.

Remember, if you run the generator without a load, you’re not testing how it will cope with a real load. It only proves the set will start and produce power, not how it will perform in real life.

These generators power essential services, so they must be able to connect to the load almost instantly. Used this way, the engine control governor and automatic voltage regulator provide a stable frequency and voltage waveform. However, these vital components aren’t tested unless the machine is loaded. We realise it’s not practical for you to carry out your own load tests. Apart from the fact it’s difficult to test 100% of load, you probably can’t afford the short period of downtime while the generator takes up the load.

That’s why we recommend the following routine:
1. Schedule a 100% full load test using a mobile artificial load bank.
2. Install a load bank circuit breaker/connection point with a shunt trip circuit activated from the mains failure starting signal. This automatically disconnects the load bank, allowing the generator to supply the essential services in the event of a utility failure during a planned load test.

To find out more contact 

Can't find what you're looking for?

If you can't find what you are looking for, please don't hesitate to get in touch with us.

Contact Us