Load Bank Testing Flashcards

What is the primary reason a generator set should be operated at a minimum of 30% rated load during a load bank test?

Answer: To prevent wet stacking in diesel engines

Operating below 30% load causes unburned fuel to accumulate in the exhaust system, a condition known as wet stacking.

During a load bank test, the kW load is stepped up in increments. What is the typical step size used for standard acceptance testing?

Answer: 25% of rated kW per step

Standard EGSA acceptance testing protocols use 25% load steps to evaluate generator response and stability.

A resistive load bank draws power at what power factor?

Answer: 1.0 unity

Resistive load banks convert all electrical energy to heat, resulting in unity (1.0) power factor with no reactive component.

Which instrument is most critical for monitoring engine health during a load bank test on a diesel generator?

Answer: Exhaust temperature pyrometer

Exhaust temperature monitoring reveals overloading, fuel system issues, and turbocharger performance during load testing.

What does a significant voltage drop under load during a load bank test most likely indicate?

Answer: The AVR or alternator excitation system has an issue

Excessive voltage drop under load points to automatic voltage regulator (AVR) problems or inadequate alternator field excitation.

A reactive load bank test is performed primarily to evaluate the generator's ability to handle what type of load?

Answer: Inductive motor and transformer loads

Reactive (inductive) load banks simulate real-world motor and transformer loads that demand kVAR in addition to kW.

When performing a load bank test, why should the cooling air inlet and outlet be kept clear of obstructions?

Answer: To avoid overheating that could cause engine shutdown or damage

Restricted airflow causes the engine and alternator to overheat, potentially triggering thermal shutdowns or causing permanent damage.