Load Bank Testing

What is Load Bank Testing?

A load bank test involves a type of assessment and examination of a generator, to ensure that it is working as efficiently as possible and in good condition. As generators are used primarily for emergency situations where you are in need of power, it is important that the generator is running properly.

Our specialist team can carry out a load test for you; if your generator is not exposed to higher than 30% of its rated kW load. We will test the time of how the kW load increases and record the data and measures. If you feel like your generator is in need of load bank testing, then give us a call today and we will be able to conduct a test for you and advise you on how to move forward.

Having a backup ready to go

Bellwood Rewinds Ltd offer Load Bank Testing as part of our comprehensive services which covers the repair, maintenance and servicing of new and old generators.

Load Bank Testing is a precautionary measure which has been put in place by experts to ensure that, in the unfortunate circumstance of your power failing, you will have a solid backup power source ready to kick in almost as soon as you can say, “The power’s gone!”.

Preventative maintenance is an important aspect of any commercial set up, and should be considered on a quarterly, annual, or bi-annual basis, depending on what you do and where you work. It’s vital for you to have these routine checks carried out as failure to do so could cost your company thousands if both power sources were lost, even for a short period of time.

The Importance of Load Bank Testing?

A load bank test is used to test the UPS and generator which is under load conditions to ensure that they are working optimally. This method is a way of validating the true operational performance as well as the battery autonomy used in UPS system. The main reason for testing load banks is to carry out preventative maintenance necessary to avoid future damages or breakdowns. In addition to preventative maintenance, load bank tests are used to ascertain the current conditions of UPS batteries as well as battery sets to show whether any of the cells are holding the charge, approaching the end of their working life or whether they are about to fail.

This facilitates their replacement before they cause a critical application problem. It is important to note that load bank test services are sometimes offered by suppliers of power protection equipment e.g. Uninterruptible Power Supplies Limited as a part of UPS commissioning process.

However, when carrying out this commissioning, caution should be exercised to ascertain reliable results and operations. Ideally, the testing services should be carried out at least after a week after the UPS has been commissioned. This is very vital because it not only permits the voltage across the battery but also allows the battery to be fully charged. You should understand that carrying out load bank tests before a week of commissioning would neither yield accurate results nor give you the true picture how the system is running. Therefore, this would be a waste of time and money and should be avoided.

"Finding a reliable and reputable company to make sure we were prepared for all eventualities was a concern. Thankfully we found Charles at Bellwood Rewinds!"

- Steve Richardson

How Does a Load Bank Test Work?

When a load bank test is implemented, an artificial load is placed on the generator. The test is timed and gradually increases the kW load in specific increments. Each time the kW load is increased, engine and alternator parameters are recorded.

Testing the generator’s ability to handle the boost, and its ability to continue functioning at the highest possible level for a sustained period. The equipment needed to complete the test includes a load bank. For more information and to see some load bank tests in action be sure to check out our video above that includes examples of our technicians performing load tests at our facility.

The actual testing procedure itself is not too complicated but does take a bit of knowledge in how the process works. The basic process features a few commonly understood steps.

  • Step One – All fluids are checked to ensure the fuel tank is full and the correct oil level is achieved, if the generator is water-cooled it is also important to check the radiator.
  • Step Two – Your generator is started in order to reach normal operating temperature. Our technicians will watch and listen for any possible issues, if any problems are detected our engineers will stop the testing process until the mechanical failure is diagnosed and fixed.
  • Step Three – Our technicians will begin by connecting loads starting with any large 200 volt loads and continuing to add smaller 110-volt loads. This is continued until each leg carries 50% of any one leg.
  • Step Four – One of our technicians will then check the amperage of each leg with an ammeter, the voltage of each leg is recommended to fall between 105 and 125 volts. The current should be half of the rated watt output divided by the voltage for each leg; if a leg falls below 105 volts at its full load there is a problem and the test is considered a fail.
  • Step Five – Your generator will be monitored while maintaining the same load for the duration of the test and continues to listen for noises and monitors the output. If an issue is discovered, the test is then shut down to minimise any damage until the repairs happen.
  • Step Six – When the test is finished, the loads are gradually removed from the generator is allowed to run under a light load for about an hour. All loads are then removed 5 to 10 minutes before shutting the generator down.

Benefits of Load Bank Testing

At Bellwood Rewinds, we would recommend that you get a load bank test every year, to make sure that the generator is working and running to the necessary standards. There are many benefits to getting your generators regularly checked. Some of these include:

  • Provides assurance
  • Helps to avoid wet-stacking – this is a condition in diesel engines where unburned fuel passes on into the exhaust system and builds up.
  • Can test for any problems that could turn into future issues
  • Bellwood Rewinds Ltd are able to offer Generator Load Bank Testing for a wide variety of generators. The test will look at all key components of the generator and will involve our team of dedicated engineers looking at your generator to see if it is in fine working fettle.
  • What’s the point in having a back-up power source, such as a diesel generator, if it doesn’t work when it is asked to do so?

With that being said, we encourage any business or company using a generator to consider Load Bank Testing. A thorough form of preventative maintenance that could spare you the embarrassment of completely losing power, and of course money and wasted time too.

Benefits of Load Bank Testing

Load Testing is a common phrase that is used a lot in the generator industry. People quite often ask us the question; “What’s the point in that? I hardly ever run my generator?”. When winter comes round, more power is demanded from the grid which could lead to more “power-cuts”.

Have you load tested your generator?


Testing your standby generator is imperative, even if your generator only runs once a year, weekly or daily it is important to test your stand by generator. Did you know that even on a regular test with a light load leaves the generator prone to faults incurred through under use or neglect?

Bellwood Rewinds recently received a 45kVA Perkins set for refurbishment, and although this set had been running prime for the last 4 years on site, after we had stripped it down there was an astonishing amount of carbon build up within the engine. This happened because of a light load and the generator not being maintained at regular intervals.

Load testing ensures that, when needed, your standby generator is in peak condition to bear the load of your power requirements. Diesel standby generators that aren’t ran often can build up fuel deposits in parts of the engine which may leave your standby generator with reduced output when it is needed in an emergency.

load bank testing

For Load Bank Testing, Contact Bellwood Rewinds

At Bellwood Rewinds we recommend load bank testing for generators at least once a year. The team at Bellwood Rewinds provide an extended and full load bank package for testing generators, whether you’ve hired the generators directly from us or already have your own on-site.

The team at Bellwood Rewinds will be more than happy to help, call us today to book in your load testing or for more information contact one of our friendly team members today.