Load testing is often confused with ‘load testing’ for software – a testing technique used to observe a system’s behaviour and determine it’s performance level by measuring its speed or capacity.
However, in engineering, load testing on generators are completely different from the software technique.
Just like many other tests, a load test is used to determine a generator’s performance and condition – aspects like characteristics of the system and quality of the components are revealed. Once a general idea of the generator’s health is received, the engineer will then proceed to take any necessary action such as generator rewinding or replacements – to get the equipment back in its original state, or better condition.
Now that you’ve somewhat understood what load testing is about – what can you expect when the engineer is doing a load test on your generator?
1. Thoroughly check each component
Before your engineer identifies any error or fault in your generator, he will first make sure that every component is operating correctly.
For instance, for a water-cooled generator – the primary focus would be to check the fluid levels. The engineer will go on to check the fuel tank and the coolant or radiator tank to ensure it’s full – while ensuring that the oil level is correct as well.
2. Spot any faults
Turn on the generator and let it reach its regular operating temperature. The engineer will observe and look out for any possible issues or listen for any unusual noises. Once any faults are noticed, the engineer will deal with them before continuing on with the test.
3. Connect the loads
The engineer will start to connect the loads, and while it is good to start with any huge 220-volt loads and add smaller 110 volt-loads til every leg comprises about 50 percent of the greatest continuous rated load – taking note that the sum should not be exceeded – he will know what amount of volt loads should be used best.
4. Check the amperage of each leg
Using the ammeter, the engineer will take a look at the amperage and voltage of each leg to be neutral with the volt-ohm-milliammeter (VOM) set. A 110/220 volt single phase generator should have the voltage of each leg falling in between 105 and 125 volts. Whereas the current should be 50 percent of the rated watt output over the voltage amount, for every leg.
Once the engineer has noted that any one of the legs, or both, have dropped below a certain amount of voltage at maximum load – then it would mean that the generator has not passed the test and requires immediate repair. Generator overhauling is an option to consider as the engineer will dismantle the equipment and make sure to check every part carefully for any necessary repair.
5. Observe the generator
Whilst the load is being maintained during the period of the test, the engineer will continue monitoring the generator even closely. Key things to look out for would be monitoring of the output, overheating and any abnormal noises. Once a problem occurs, the engineer will turn off the equipment immediately to minimize any damage and have it repaired to return its original condition.
The duration of the test is dependent on the generator type. It is best to operate larger industrial quality diesel generators under maximum load for approximately one week. While smaller ones like light-duty portable generators are not supposed to be operating at maximum load for over three to four hours.
6. Take out the loads and let it operate
Slowly, the engineer will remove the loads once the test has ended and let the generator operate under light load for about an hour. He will take note to have them removed around five to ten minutes before turning the generator off.
Pros of doing load testing
1. Save time trying to pinpoint the source of a fault or error
2. Verify the generator’s performance level
3. Ensure system compatibility
4. Know if immediate repair is needed
5. Ensure reliability of the generator
While there are many different types of tests that an engineer can do to assess your generator’s condition – load testing is among the variety of tests that should be considered before proceeding to do generator maintenance in Singapore.
Needless to say, other equipment requires proper assessment as well – such as motor and switchgear testing. So, before you make the decision to do any repair, run one or two tests to confirm it and fix your generator.