Power Generation Equipment Flashcards
7 cards from real EGSA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Power Generation Equipment flashcards as text
What causes harmonic distortion in a generator's output voltage waveform?
Answer: Non-linear loads such as variable frequency drives and switch-mode power supplies
Non-linear loads draw current in pulses rather than sinusoidally, injecting harmonic currents that distort the generator's output voltage waveform.
When two generators are being synchronized for parallel operation, which parameter must be matched last to avoid circulating currents?
Answer: Phase angle
Phase angle is matched last (at closing) using a synchroscope or sync check relay to ensure the breaker closes at the exact moment the phase angles align.
What is the purpose of the anti-condensation heater installed in a generator alternator?
Answer: Prevent moisture condensation on alternator windings during shutdown periods
Anti-condensation heaters keep alternator windings slightly above ambient temperature during standby to prevent moisture from condensing and degrading insulation resistance.
Which factor primarily determines the synchronous speed of an AC generator?
Answer: Number of magnetic poles and operating frequency
Synchronous speed (RPM) = (120 × frequency) / number of poles; a 4-pole generator must spin at 1800 RPM to produce 60 Hz output.
What is the primary hazard of operating a generator with a single-phase load heavily unbalanced across phases?
Answer: Overheating of the most heavily loaded phase winding and neutral conductor
Severe phase unbalance causes one phase winding and the neutral conductor to carry excess current, leading to overheating and potential insulation failure.
In a diesel generator fuel system, what is the purpose of the day tank?
Answer: Provide a local fuel supply close to the engine to ensure reliable fuel delivery and gravity feed
The day tank is a small local reservoir that gravity-feeds fuel to the engine, providing reliable delivery independent of the main bulk storage tank pump.
What type of circuit breaker trip unit is required to coordinate with generator subtransient fault currents?
Answer: Electronic trip unit with adjustable long-time, short-time, and instantaneous settings
Electronic trip units with adjustable settings allow coordination with the generator's subtransient, transient, and synchronous fault current levels across multiple time bands.