Resistive vs Reactive – Reasons to Choose Reactive Load Bank Testing Solutions

Fully functional backup systems remain critical to business success. In the event of an unexpected power outage, you need to know your operation will continue seamlessly.

However, many facilities managers don’t understand the risks they actually face with their backup systems. Although you may conduct regular tests of their equipment, your operation may not be adequately protected. Too often, facilities managers perform tests solely on a component-by-component basis and forgo system-wide testing. Failure to test the entire system may hide system weaknesses. 

Using load bank testing solutions, you’re able to confirm functionality by simulating real-world scenarios. Load testing validates the operational performance of electrical and mechanical systems, including generators, uninterruptible power supply (UPS) equipment, power distribution units (PDUs), battery backups and cooling systems. Facilities managers typically perform load testing during commissioning of a facility, installation of new equipment and as part of a preventative maintenance program.

Load bank testing uncovers issues in a controlled situation before an actual power outage. Providing the only way to verify system functionality, load bank testing enhances the reliability of your operation and minimizes the risks associated with an unexpected power failure.

Types of Load Bank Testing Solutions

Available in a variety of sizes and configurations, load banks measure commercial loads. Typically, these loads consist of a combination of motors, heating, transformers and lighting.

Three main load bank testing solutions exist:  resistive, reactive and resistive/reactive:

  • Resistive Load Banks The most common type, resistive load banks mimic the operational load that a power source will see in actual use. They convert electrical energy (current) into heat using power resistors and dissipate the heat using air or water. Examples of resistive loads include incandescent lightbulbs and devices with heating elements, such as space heaters and hot plates.
  • Reactive Load Banks – These solutions are used to simulate systems affected by electric motors or other electromagnetic devices on a power network. In general, equipment that requires reactive power compensation are motor-driven devices, transformers and capacitors.

Reactive load banks can simulate either an inductive or capacitive load depending on the type of load expected on the power system. A reactive/inductive load converts current into a magnetic field. It resists the change to voltage, causing the circuit current to lead voltage. Examples of devices producing reactive/inductive loads include motors, transformers and chokes.

Reactive/capacitive load charges and releases energy. It resists the change to voltage, causing the circuit current to lead voltage. Reactive/capacitive load bank testing is often conducted in telecommunications, solar, manufacturing and mining applications.

  • Resistive/Reactive Load Banks These solutions combine both resistive and reactive elements in one load bank package. Resistive/reactive loads are able to mimic motor loads and electromagnetic devices within a power system, as well as provide purely resistive loads by allowing to set a specific power factor.


Resistive/reactive load banks are used for testing turbines, switchgear, rotary UPS, generators and UPS systems. They can also be used for integrated system testing of utility substation protection systems and solar inverters.

The Drawbacks of Resistive-Only Load Testing

Emergency power generation involves a complex system consisting of many different parts. And, any single part is subject to failure at any given time. In addition to testing the individual components, you need to ensure your entire system functions as required.

However, many facilities managers skip the system-wide testing because of complexity, time constraints and cost. Instead, they often use a resistive load bank to test only the generator engine, which fails to simulate real-world conditions. 

In addition, resistive loads comprise only a small part of a facility’s total power consumption. Testing only resistive loads won’t determine how well your system will function during an emergency power outage. Conducting a complete system test simulating a real load is the only way to ensure all individual components will work together in harmony.

Making the Case for Reactive Load Bank Solutions

Reactive solutions simulate systems affected by electric motors or other electromagnetic devices on a power network. And resistive/reactive combination load banks can test the entire generator system at its rated power factor. Unlike resistive-only testing, a resistive/reactive test can predict pending failures of the multiple components making up the entire system. 

Resistive-only testing cannot create the conditions experienced during a real power failure. Only a properly configured resistive/reactive load test will ensure your complete system operates at an acceptable level during an emergency. 

Proper system-wide resistive/reactive load testing helps uncover weaknesses in your power generation system and prevents unexpected failures during emergencies. Understanding what load testing solutions to deploy and how to conduct effective testing will help mitigate the risks associated with unexpected power outages.

Download eBook for More Information…

For a more detailed discussion on resistive versus reactive load bank testing, download ComRent’s latest eBook today. This resource will discuss the importance of using load bank testing for a facility’s entire emergency power generation system. It will provide an overview of load bank testing, explain the different types of load banks and outline the most beneficial load bank solutions for most applications.

ComRent’s team of experts is ready to help ensure your system is successfully interconnected. We are offering a complimentary consultation to review your project and propose the right load bank solution for your application. Contact us today at 888-881-7118 or visit our website for more information on load bank testing.

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