Standby generators are non-functional most of the time — their purpose is to supply electricity during an emergency. To conduct a load test, connect the load bank to the generator and allow it to run until it gradually reaches 100-percent capacity. The next step entails moving the manual or automatic transfer switches (ATS) to their emergency settings. You should then apply the electrical load until it reaches the desired load level. Upon completing the test, remove the load bank and return the transfer switches to their regular position.
The results of load bank testing will indicate the status of a variety of key generator performance factors, such as:
- The ability of the engine to achieve an acceptable output
- Oil pressure of the generator and whether it’s at the optimum level
- Stability of the voltage
- Presence of fuel, oil or coolant leaks
- The efficiency of the system during various load conditions
When Should You Use Generator Load Bank Testing?
You should perform load bank testing as part of your generators’ preventive maintenance program. If you use your generators frequently, you may not need to conduct regular testing. However, backup or standby generators should be tested often to assess their emergency readiness. As a rule of thumb, if a generator operates at under 30 percent of its kilowatt nameplate for less than 30 minutes per month, you should use a load bank to produce an artificial load and test its performance on an annual basis.
Benefits of Load Bank Testing
Resistive load bank testing for generators provides a host of benefits, such as:
- Removing carbons and other foreign materials that can negatively impact generator engine performance
- Minimizing the risk that the generator will not perform at full capacity during an outage
- Verifying the capacity of the UPS batteries and the integrity of all electrical connections at the time of testing
- Reducing the likelihood of wet stacking, a potentially harmful condition caused by unburned diesel fuel building up in the generator engine exhaust system
- Alleviating extra stress on the engine that can lead to poor performance and potentially cause mechanical failure
- Providing you and your team with the confidence that your generators will operate at full capacity when the need arises