Benefits of Resistor Load Banks for Industrial Applications

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Testing the capacity and fitness of a generator or power supply before going live is vital to success in the field. Likewise, maintaining the operation of these devices — especially in diesel applications — is both an insurance policy against failure and a sound cost-avoidance measure. To achieve these goals, you need the right equipment to successfully test loads and diagnose issues. 

In this post, we’ll share information on load banks and how they work, the different options for load banks, and how to choose the best type for your particular industrial application.  

What is a load bank?  

A load bank is a piece of testing equipment that simulates electric load in a controlled way.  

Load banks simulate and test the full load capacity of a diesel engine, gas generator, motor, uninterrupted power supply (UPS), or other power system. Testing with a load bank before connecting it to a real power source helps identify potential faults and weak points within the system that could impede its performance under expected operating loads. Load banks can also test backup systems in case of a power outage or other emergency, ensuring they are ready for activation when needed. 

How does a load bank work? 

Load banks use heavy-duty resistors to dissipate energy as heat. To manage heat output, the load bank uses air or water cooling to dissipate heat efficiently and maintain normal operating temperatures.  

How does a load bank protect equipment? 

A load bank controls power flow to prevent damage to expensive and sensitive equipment. It also provides metering to test electrical output safely and prevents system overloads.  

In diesel applications, a load bank protects engines and generators from “wet stacking,” which occurs when diesel engines are operated at less than full power. It causes unburned fuel to collect in the exhaust system and form a dense, wet film on the walls of the engine's cylinders. This increases fuel pressure, resulting in higher operating temperature that can cause damage to the engine if not resolved. 

What conditions can a load bank help identify? 

Load banks provide a wealth of information about the health and reliability of a generator, battery, power bank, or motor. 

Battery performance: Testing with a load bank helps crews determine if a specific generator or battery is fit for service before it goes into the field. A successful load test means that the battery will perform nominally in an event like a power outage. 

Stability testing: Supply isn’t the only factor in the health of a power source. Testing alternator capability ensures that the alternator will provide necessary voltage stability during operation. 

Track engine performance: Using a load bank helps test a generator engine’s ability to provide consistent power in the field.  

Oil and fuel pressure gauge: A load bank can identify issues within the oil or fuel pressure systems of a malfunctioning unit so that a technician can repair it and return it to service. 

Deposit buildup: Technicians also use the load bank to identify buildup in malfunctioning units such as fuel coagulation or carbon deposits around UPS pistons or exhaust vents.  

Types of Load Banks 

There are two main types of load banks to choose from in industrial applications: Reactive and resistive. Each has capabilities that make them suited to certain applications. We’ll explore their differences and help you choose the best load bank type for your purposes. 

Reactive Load Banks 

Reactive load banks use inductors or capacitors to simulate loads. They’re well-suited for testing components of an alternating current (AC) power system, and those that may be affected by magnetic fields, such as transformers. Reactive banks maintain a constant power factor by providing reactive current, which can replicate the behavior of real-world loads on AC systems. This allows technicians to evaluate the performance and accuracy of a unit’s voltage, frequency, and power factor before it is put into service. 

Reactive load banks can be classified as reactive-inductive and reactive-capacitive load banks. Reactive-inductive load banks harness the electrical current to create a magnetic field in equipment such as motors and transformers, while reactive-capacitive load banks facilitate the charge and discharge of energy in devices utilizing solar or telecommunication. 

Resistive Load Banks 

Resistive load banks are made up entirely of resistance elements that create a true ohmic load when connected to a circuit. They are the most common and most versatile type of testing bank. These load banks can test direct current (DC) or AC devices, such as small and large portables, AC trailer-mounted units, medium/high voltage units, and DC portable devices like turbines. They also draw larger amounts of current than reactive load banks, making them more suitable for large industrial applications that require high-power output testing. 

Resistive load banks are often the better choice for industrial applications due to their versatile form factor, ability to handle applications from 150KW to 100 MW, high capacity output (up to 100% of expected load), and usefulness in common diesel applications. 

Choosing the best resistive load bank for your testing needs 

Choosing the right resistor depends on its construction and surrounding components. Industrial systems need various parts to work together reliably under heavy loads, from high-voltage surface mount chips to load banks. Due diligence on each component is crucial when configuring mission-critical systems.  

About Ohmite; 

Ohmite has been the leading provider of resistive products for high current, high voltage, and high energy applications for over 95 years. Our full complement of resistor construction includes wirewound, wire element, thick film, and ceramic composition. We also lead the way in thermal management for resistive and other technologies offering a vast array of heatsinks. Contact our team today to learn more.