When an outage strikes, you rely on your standby generator to keep your operations running until you can solve the problem. This is especially true for critical organizations such as hospitals, where prolonged outages are literally a matter of life and death.
Load bank testing helps you prepare for these emergency situations by confirming that your generator can take on and sustain operations at full load for a long period of time. Regular load bank testing is also key to your preventive maintenance regimen because it promotes generator health and helps you identify mechanicassues that could escalate.
In this post, we'll explain what load bank testing is and why it's so vital for generator health and maintenance. We'll also discuss the steps technicians follow when conducting load bank testing and the importance of hiring the right technician for the job.
What Is Load Bank Testing?
Load bank testing is an essential component of any preventive generator maintenance routine. It consists of a test that applies an artificial load to a generator to verify that it can sustain operations at full load for a set period of time.
Wet stacking typically occurs in generators that are used only in emergencies, or that typically operate under light loads. Because the generator does not reach a high enough operating temperature, unburned fuel and debris build up in the exhaust system. This buildup can cause serious internal damage that impacts generator performance. It can also become a fire hazard.
A generator load test raises a generator's operating temperature, which burns off excess fuel buildup and tests the system's ability to handle high loads.
It's important to note that many generators run automatic exercising, but this function is different from load bank testing. Unlike load bank tests, automatic exercise is usually conducted under a light load, or without applying a load at all.
What Is a Load Bank and How Does It Work?
A load bank is a device that applies an external electrical load to a generator to test its performance capabilities. There are four primary types of load banks:
- Resistive: Resistive load banks are the most common type of bank and are typically used for general-purpose generator sets. They usually contain a built-in cooling unit, though some units lack this feature and rely on external airflows for cooling.
- Reactive: Reactive load banks are less common than resistive models, but they're the most effective type for testing emergency generators in business-critical operations such as in data centers and hospitals.
- Resistive-reactive: Resistive-reactive load banks combine reactive and resistive testing methods for applications where both are necessary.
- Inductive: Inductive load banks use electromagnetic fields to test power equipment. They are typically used to test rotating devices like motors.
When you conduct a load bank test, you want to make sure you use the right type for your generator set and application. They also come in various configurations to suit multiple different generator types. Consult a load bank expert to find out which configuration best fits your application.
Depending on how often you need to test your generator set, you could either purchase a load bank and keep it onsite or rent one as needed.
What Are The Benefits of Load Testing?
Load bank testing is beneficial for a variety of reasons, including:
- Generator longevity: As your generator ages, it's likely to experience increasing problems over time. Load bank testing burns off wet stacking and eliminates carbon deposits, which reduces the risk of internal damage and extends the life of your generator.
- Cost savings: Load bank tests can reveal generator issues before they become serious problems, which can prevent costly repairs and future mechanical failures.
- Continued compliance: Industries that rely on backup generators to keep mission-critical operations running during outages and other emergencies should perform load bank tests every month to comply with National Fire Protection Association (NFPA) standards.
- Peace of mind: Running routine generator load bank tests confirms that you can rely on your backup generator to power your business when you need it most.
What Does Load Bank Testing Involve?
Because load bank testing is a highly technical procedure, you'll need a qualified and experienced technician. Your internal maintenance staff might lack the proper training or experience to safely conduct the test, so you may want to consider hiring a certified operator from a reliable power systems provider.
Before conducting a generator load bank test, the technician should take the proper precautions to ensure safety. Technicians should wear personal protective equipment (PPE) such as eye protection, hearing protection, gloves, steel-toed boots, and a high-visibility vest. They should also check all fluid levels, including fuel, oil, and coolant, to ensure the generator is ready to handle a full load.
To conduct a load bank test, one ususally usually follows these steps:
- Connect the load bank to the generator using the attached cables.
- Turn on the generator and allow it to run until it reaches normal operating temperature.
- Begin applying loads in descending voltages until each leg carries half of the generator's maximum continuous rated load.
- Using an ammeter, check the voltage and amperage of each leg.
- Once the testing period is over, gradually remove the applied loads and allow the generator to continue running under a light load for about an hour.
- Remove all remaining load five to ten minutes before shutting the generator down completely.
Monitor the generator throughout the testing period to ensure everything goes as planned. If at any time you hear or see signs of mechanical issues, stop the test. Wait to test again until the issue has been diagnosed and resolved.
Additionally, be sure to follow lockout/tagout procedures as required by the NFPA and the Occupational Safety and Health Administration (OSHA) to prevent fire hazards or personal injury.
The load bank test report should include the following information:
- Applied load in kW
- AC voltage
- Frequency in hertz (Hz)
- Voltage tested
- Amperage rating
- Oil pressure
- Additional notes or concerns
Test Your Generators With Thompson Power Systems
If you're looking for efficient load bank testing services, Thompson Power Systems is here for you. We've been serving businesses throughout Alabama and the Florida Panhandle for more than 60 years, so we've got the knowledge and the experience necessary to help you keep your business running.
You can count on our team of skilled experts to perform effective preventive maintenance procedures on your power systems, including load bank testing for all your generator sets. We also have a wide range of new, used, and rental power equipment from Caterpillar to fit any industry and application.
Click here to find your nearest location, or give us a call at 205-782-0952 for more information about our products and services.