Established 1981

Load Bank Testing

Load bank testers are used in place of a facilities load. This device develops an electrical load to test for generator output power. Load banks can be defined as a self-contained, unitized, systematic device that includes load elements (system that tests emergency generator and associated systems).

Diesel Service and Supply offers the following load bank testing services:
  • Resistive Load Bank Testing
  • Reactive Load Bank Testing
Resistive Load Bank Testing
Resistive load bank testers (Figure 1) are the most common type of the two styles of load bank testers. Banks of resistors simulate the load. The resistive load simulates loads such as, lighting, motors and transformers.
The load bank tester is connected directly to the generator output. As the load bank tester increases demand, the following generator systems are tested to full capacity:
  • Generator – Voltage and amperage at rated load
  • Enclosure Louvers – Opens when enclosure temperature reaches rated temperature
  • Engine Fuel System – Insures engine fuel system functions while fully loaded
  • Engine Cooling System – Coolant temperature can be monitored under actual generator load
  • Engine Air Intake System – Insures air intake system (louvers can be included) operate when demanded
This testing will not allow the generator to produce the full Kilo-Volt Amperage (KVA) rating. KVA is absolute value of complex power equations. A volt is considered electrical pressure and an Amp is considered electrical current. KVA is the product of the amperage and voltage.

Figure 1, Resistive Load Bank Tester

Reactive Load Bank Testing
Reactive load bank testers (Figure 2) are used to test the generator set at its rated power factor. Power factor is the measure of how efficiently the load (current) is being converted into useful work output. It is a good indicator of the effect of the load (current) on the efficiency of the generator. A power factor of 1 would indicate 100% efficiency. Most generators run with a power factor of .8 (80%) efficient.

The three types of testers are commonly used are:
  • Inductive – The major component in this tester is an iron core reactive element. When used in conjunction with a resistive load tester creates a lagging power factor load (current out of phase with voltage).Used for loads consisting of lighting, heating, motors, transformers etc.
  • Capacitive – The major component is this tester is the capacitor bank. The operation principle is similar to the inductive system. The dielectric material in the capacitors change the power factor to a leading power factor. The load provided by this unit simulates electronic or non-linear loads typical of telecommunications, computer or UPS (Un-interruptible Power Supply) industry
  • Electronic Load Bank – Fully programmable, air or water cooled design. These testers are used to simulate a solid state load and provide constant power for precision testing
Figure 2, Reactive Load Bank Testing Bay