Load Bank Testing: Know How it Works

An uninterruptible power supply (UPS) is placed between a protected load and a secondary power source, such as a standby diesel generator (uninterruptible power supply). Most uninterruptible power supply units (UPS) are designed to continuously power connected loads through their inverter, which also permits conditioning of the mains supply voltage and the guarantee of a break-free supply of energy in the case of a mains failure. Most software considers UPS essential for continuing business operations since loads cannot operate without it in the case of a power outage. UPS systems are put through load bank testing to guarantee they will work well under pressure.

The UPS system’s battery life and operational efficiency may be tested and confirmed using a UPS load bank test. The UPS and the backup generator will be put through their paces under heavy load. Preventative maintenance is the typical context for this kind of work. UPS batteries and battery sets (sometimes known as “strings”) may be evaluated using DC load bank testing to find out whether any cells are towards the end of their useful life, not retaining a charge, or are on the brink of failure. This allows for their replacement just before a mission-critical deployment.

Why do we even bother with load bank testing?

Similar to how racing car components may be tested in simulators to determine how they perform under pressure without endangering the safety of the actual vehicle, the goal is to test the power protection system (and its parts) under load circumstances without endangering supply to protected loads.

In the same way that a fire alarm is seldom noticed until a fire suddenly goes off, the issue with UPS is that its users feel they will never need to put it to serious use. But what if it didn’t? The same reasoning applies to the UPS load bank test and other forms of power protection: the worst time to find out about a problem is when the mains power goes out. UPS and fire alarms should be tested regularly to ensure they work properly. Turning on a generator alone isn’t enough. Managers need to know that it can keep running even if all its slots are filled. Load bank testing is similar to a road test in that it puts a power protection system through its paces in a controlled environment before a confident “Yes, that works” can be given.

What is the procedure, and what does it reveal?

Load banks should be no more than 20 meters from the output power distribution unit or UPS terminals, so long as the cables connecting them are adequately rated (PDU). Load banks are outfitted with blowers and heaters to regulate temperature and muffle sounds during tests. It would help if you didn’t do this anywhere near humans, sensitive alarms, or sprinkler systems.

Discharge measurements may be used to evaluate battery and system performance. In case of a UPS load bank test or generator problems, a load bank test can quickly diagnose the problem and advise on any required repairs. Performing a DC load bank test on a standby generator will disclose information such as the engine’s power output capability, the alternator’s voltage and frequency stability, the operation of the complete system under different loads, and the oil and fuel pressure. It will also help remove deposits from exhausts, engine castings, and pistons, identify potential weak places and keep track of results and necessary maintenance.