EGSA Generator Set Maintenance 5 — Questions and Answers
Question 1: What is the primary reason for performing a coolant analysis as part of a generator set preventive maintenance program?
- To check fuel contamination levels
- To monitor glycol concentration, pH, corrosion inhibitor depletion, and contaminant levels before failures occur (Correct answer)
- To verify thermostat calibration
- To measure coolant pump output pressure
Correct answer: To monitor glycol concentration, pH, corrosion inhibitor depletion, and contaminant levels before failures occur
Coolant analysis detects depleted corrosion inhibitors and contamination that would otherwise cause internal corrosion and premature cooling system component failure.
Question 2: A generator set produces normal voltage at no load but the voltage collapses significantly under full load. Which component is most likely the cause?
- Weak excitation from a faulty AVR or under-sized exciter winding capacity (Correct answer)
- Faulty engine speed governor
- Defective battery charging alternator
- Blocked fuel filter causing engine under-speed
Correct answer: Weak excitation from a faulty AVR or under-sized exciter winding capacity
Voltage collapse under load is a classic sign that the excitation system cannot supply adequate reactive power, indicating AVR, exciter winding, or PMG failure.
Question 3: During maintenance, a technician finds that the fuel day tank low-level alarm activates correctly but the automatic fill pump does not start. What is the first component to check?
- The main fuel storage tank level
- The fill pump control relay or float switch wiring continuity (Correct answer)
- The generator's governor
- The automatic transfer switch logic board
Correct answer: The fill pump control relay or float switch wiring continuity
When an alarm activates correctly but the associated pump fails to start, the control circuit between the alarm and pump — typically a relay or wiring connection — is the first suspect.
Question 4: What is the correct action when the oil analysis report shows a significant increase in iron (Fe) content compared to the previous sample interval?
- Extend the oil change interval since the oil is absorbing more metal particles
- Investigate for accelerated internal engine wear and schedule an inspection before the next planned service (Correct answer)
- Switch to a higher viscosity oil grade immediately
- Increase the load on the generator to improve lubrication
Correct answer: Investigate for accelerated internal engine wear and schedule an inspection before the next planned service
A rising iron trend in oil analysis indicates abnormal wear of ferrous engine components such as cylinder liners, piston rings, or crankshaft, requiring immediate investigation.
Question 5: What maintenance procedure helps prevent starting system failure caused by diesel fuel gelling in cold weather operation?
- Installing a higher output starter motor
- Using winter-blend fuel with appropriate CFPP rating and installing engine block heaters (Correct answer)
- Reducing oil viscosity to a lighter grade
- Increasing battery float voltage by 0.5V above normal
Correct answer: Using winter-blend fuel with appropriate CFPP rating and installing engine block heaters
Winter-blend diesel with a Cold Filter Plugging Point (CFPP) appropriate for ambient temperature, combined with block heaters, prevents fuel gelling and ensures reliable cold-weather starting.
Question 6: When conducting a generator set maintenance inspection after a fault trip on overcurrent, which component should be inspected for signs of damage before resetting and restarting?
- Air intake ducting
- Alternator windings, connections, and circuit breaker contacts for signs of overheating or arcing (Correct answer)
- Engine speed sensor
- Radiator hoses and clamps
Correct answer: Alternator windings, connections, and circuit breaker contacts for signs of overheating or arcing
An overcurrent fault can cause thermal damage to alternator windings and arc erosion on breaker contacts; these must be inspected before returning the unit to service.
Question 7: What does the EGSA maintenance standard recommend regarding documentation of generator set maintenance activities?
- Documentation is optional for units under 5 years old
- Comprehensive written maintenance records should be kept to track service history, trends, and support warranty claims (Correct answer)
- Only major component replacements need to be documented
- Digital-only records are not acceptable per EGSA standards
Correct answer: Comprehensive written maintenance records should be kept to track service history, trends, and support warranty claims
EGSA standards emphasize maintaining comprehensive written service records to enable trend analysis, verify warranty compliance, and support reliable long-term operation of generating equipment.
EGSA Generator Set Maintenance 5
What is the primary reason for performing a coolant analysis as part of a generator set preventive maintenance program?