EGSA Load Bank Testing 3 — Questions and Answers
Question 1: What parameter must be verified before connecting a load bank to a generator to confirm compatibility?
- The generator's fuel type
- The load bank's voltage and frequency rating match the generator output (Correct answer)
- The color of the generator enclosure
- The age of the generator
Correct answer: The load bank's voltage and frequency rating match the generator output
The load bank voltage and frequency ratings must match generator output to prevent equipment damage and ensure accurate testing.
Question 2: During a 2-hour full-load test, the coolant temperature gradually rises above the normal operating range. The most likely cause is:
- The load bank resistors are failing
- A restricted cooling system or low coolant level (Correct answer)
- The AVR is boosting voltage too high
- The generator is under-loaded
Correct answer: A restricted cooling system or low coolant level
Rising coolant temperature under sustained load typically indicates a coolant system restriction, low coolant level, or failing thermostat.
Question 3: What is the purpose of recording generator data at regular intervals (e.g., every 15 minutes) during a load bank test?
- To meet OSHA safety requirements
- To track parameter trends that may indicate developing problems (Correct answer)
- To calculate the generator's resale value
- To satisfy fuel supplier warranty requirements
Correct answer: To track parameter trends that may indicate developing problems
Interval data logging captures trending parameters that reveal degradation or instability not visible at a single snapshot in time.
Question 4: Which NFPA standard governs the testing requirements for emergency standby generators in healthcare facilities?
- NFPA 37
- NFPA 70
- NFPA 110 (Correct answer)
- NFPA 101
Correct answer: NFPA 110
NFPA 110 sets the standard for Emergency and Standby Power Systems, including load testing intervals and acceptance criteria.
Question 5: A load bank test reveals the generator frequency drops from 60 Hz to 57 Hz under full load and does not recover. This most likely indicates:
- A faulty AVR
- A governor or fuel delivery problem (Correct answer)
- A shorted load bank element
- A failed battery charger
Correct answer: A governor or fuel delivery problem
Frequency is controlled by engine speed; a persistent drop under load points to governor malfunction or inadequate fuel delivery.
Question 6: What safety practice must be followed when disconnecting a load bank from a running generator?
- Remove the load in steps rather than all at once (Correct answer)
- Shut down the generator first, then disconnect the load bank
- Open only the neutral connection first
- Disconnect at the load bank terminals before the generator terminals
Correct answer: Remove the load in steps rather than all at once
Load must be stepped down gradually to prevent a sudden load rejection that can cause dangerous voltage and speed spikes.
Question 7: When sizing a load bank for testing a 500 kW generator rated at 0.8 PF, what minimum kW capacity load bank is required for full-load resistive testing?
- 400 kW
- 500 kW (Correct answer)
- 600 kW
- 625 kW
Correct answer: 500 kW
For resistive-only testing, the load bank must match the generator's kW rating (500 kW), since resistive load draws at unity power factor.
EGSA Load Bank Testing 3
What parameter must be verified before connecting a load bank to a generator to confirm compatibility?