Generator Load Bank Testing – A Complete Procedure

Generator Load Bank Testing – A Complete Procedure

A standby generator can remain unused for a long period, Awaiting a power cut before smoothly working. It neglects a regular Load Bank testing for Standby Generator.

This diesel generator that runs rarely or lightly loaded over the time some parts of an engine will deposit a fuel. That’s why your standby Generator reduced the capacity of when it is required. Things like light loading or ignoring the maintenance scheduled can generate an unexpected operating cost.

In this situation, the load test will assure that your standby generator supports your load when it is required. Annually load testing ensures that your generator is capable of handling the load of demand.

Most important thing is that regular maintenance scheduled will make sure that your generator is ready when it is needed. For some places, such as Data-center, Blood banks, and hospitals emergency power Generators cannot afford to fail. That’s why maintenance technique like load bank testing is vitally important.

Load Bank testing is an essential requirement for some backup power generation applications. The Emergency power comes under the control of a  no. of the regulatory oversight committee. The National Fire Protection Agency(NFPA) and The National Electric Code(NEC) they both come under a Load Bank Testing of emergency Generator.

Load Bank

A load bank is an electrical device that temporarily wired into a Generator AC voltage output. the load is applied in a generator through switches to produce specific KW output. This allows the operator to apply specific load during the testing process to match the Generator capacity.

What Is The Reason Behind To Test Your Generator

To make sure that the generator will perform when it is needed. This is the only way to check the performance of your generator. A Load test will verify that the Generator system will produce and maintain full load without overheating and shutting down. It also allows all component of the system and to ensure that all are working together and it can help to identify the weakness of controlled conditions.

This allows proactive maintenance because weakness is identified during the controlled condition. Not during a utility outage because weakness can cause a system to fail.

The load can come from the building but it causes business interruption when transferring the utility to the generator. It is also not allowed that the load applied from steps where performance was monitored. Utilizing a portable load bank is a  method of Load Testing a Generator system.

Most of the generators will program to work regularly. This exercise work Under period no load. Monitoring the working period it will ensure that the generator start and the run program is also important.

Most Generator systems installed and put into the automatic mode. As the age of the Generator, some possible weaknesses will rise. Among the other weather, pest, and age can be negatively affected by Generator system.

A well-planned maintenance program like Load Testing is the best way to minimize the weakness of the generator system. Many of the installed Generator system that utilizes a  diesel engine it is also a challenge. And the challenge is wet stacking. If we did not address wet stacking will degrade the performance of the generator system and not allow it to operate and design.

Some system designs to operate a wet stacking problem but some systems will not eliminate a wet stacking problem. I suggest that all diesel systems will have to load tested with a minimum of two hours annually. If a diesel system has not been tested over the year. Longer testing may be required. This annual testing will reduce the wet stacking problem in the Generator system.

What is The Generator Load Bank Testing?

Generator load bank testing is an important part of a maintenance technique. Generator load bank testing is an examination and assessment of Genset. It verifies that all components of a generator are in proper working conditions.

The equipment is used to load the Bank test to produce an artificial load on the generator by bringing the engine at the appropriate temperature and pressure level. This is important for standby and emergency Generators they do not very often to carrying a heavy load on a frequent basis. If your Generator is not to higher than 30% of its rated KW load. Then you should be considering the load test.

Load Bank Test one extra or prime power generator and running it’s under  Artificial Load and at its maximum capacity for a specified amount of time. During Load Bank testing data can be recorded that offer more look into the health of Genset. The test verifies that the generator is capable of taking incremental higher KW Load that is still accommodating its maximum Load.

It can work for an extended period of time. So Load Bank testing is a way of verifying that your standby or prime power generator is still capable and operating its maximum KW


A Load Bank test ensures that your Generator runs properly when it’s needed. So that you can fully prepare for an emergency situation. The proper Load Bank Test is your generator of its full KW output. Because many of them were not regularly operate at their full KW output and especially important when you verify your Generator at highest possible. The horsepower that may be required at the same time maintaining temperature and pressure levels that allow as long as necessary. Some procedure follows to Load Bank Test :

  • Start and run the Generator until its temperature is stabilized.
  • Transfer all the manual and automatic switches to the emergency source.
  • Load the Generator with Load Bank until the desired Load is reached.
  • Remove the Load Bank first after the test.
  • Transfer all the switches back to the normal position.
  • Allow the Generator to cool down according to the guideline.

Testing Procedure Step-by-Step

When a load bank testing is done, the artificial load is placed on the Generator. The test-takes time and gradually increase the KW load in a specific increment. Each time the KW load is increased the test measurement provides an important engine parameter with the ability to handle boost and continuous functioning at the highest possible level for some time. The equipment complete the task includes a load bank.

Placing 100% on capacity load on a generator and allowing the allowing it to run for a while not only bring to light any problem in the Generator and in the engine and its cooling system. It also benefits the engine by properly seating the ring dislodging build-up in the combustion chamber and valves.

A diesel engine needs a periodic load test in order to maintain performance and fuel economy.

These Are Some Of The Steps To Test a Load Bank Testing

  • Step 1

Check all fluids level in the Generator. Make sure that the fuel tank is full, The Oil level is correct, and the radiator or coolant tank is full, If it is a water-cooled generator.

  • Step 2

Start the Generator and allow it to reach the normal temperature. And now watch listen for any potential problem or abnormal noise. If any problem occurs do not proceed with the test until you take care of them.

  • Step 3

Now connecting the load, with any large 220-volt loads and adding smaller 110-volt load until each leg carries 50% of the maximum continuous rated load of the Generator. Do not exceed more than 50% on any one leg. If possible use 220-volt resistive loads such as large space heater or water heater. they simplify this step because they applied the load to each leg equally.

  • Step 4

Check the amperage of each leg with the ammeter, and check the voltage from each leg for neutral with the VOM set to read each volt. For 110/220 volt single phase generators, the voltage of each leg should fall between 105 and 125 volts and the current for each leg divided by the voltage should be half of the rated output current.

For example, if the voltage of each leg neutral is 117 volts loaded, and the Generator is rated at 10 KW continuous each should be loaded to the 5000 divided by 117 or approximately 42 amperes. If one or both leg drop below 105 volts at full load the generator has failed the test and need repair.

  • Step 5

Monitor the best portable generator while maintaining this load duration of the test. Watch for overheating, listen to unusual noises and monitor the output. If the problem arises shut the generator down quickly to minimize the damage and repair the generator before returning it to service. How long the test should continue to depend upon the type of generator.

A small portable generator does not run more than three to four hours at full loaded. Contractor grade generator able to run eight hours. Continuous duty air or water-cooled generator should run 24 hours. Large industrial quality diesel generators should ideally be run under full load for about a week.

  • Step 6

Load remove at the conclusion of the test and allow the generator to run under light load for one hour. Remove all the loads five to ten minutes before shutting down the generator.

Need Of Load Bank Testing

  • Verifies the Genset capabilities as opposed to just routinely starting up.
  • Discover the problems in early it can be less expensive and prevent future major issues.
  • It helps to avoid wet-stacking and clean out the carbon deposits.
  • It ensures that the Genset was working properly when need it most.
  • Test that Genset is capable of working at specified KW output for a specified amount of time.
  • Burning off the residue that leads to wet stacking eases the effect of light loading.


To run an industrial generator for long it is necessary to do a generator load bank testing. It is very helpful to use a generator for a long time. The most important thing is regular maintenance schedules. This will make sure that your generator is ready at the time of need.

For some places, such as Datacenter, Blood bank, and hospitals emergency power Generators cannot afford to fail. That’s why maintenance technique like load bank testing is vitally important. Load Bank testing will ensure that your generator fully dependable and completely capable of the highest possible load

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