Prime Mover and Governors Flashcards
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Read the first 7 Prime Mover and Governors flashcards as text
A natural gas engine prime mover uses which type of ignition system, unlike a diesel engine?
Answer: Spark ignition
Natural gas engines use spark ignition because natural gas has a higher octane rating and will not self-ignite under diesel compression ratios.
What is 'transient frequency dip' in generator performance and what primarily determines its magnitude?
Answer: A momentary frequency drop upon sudden load application; determined by engine/governor response time and rotating inertia
Transient frequency dip is the momentary drop in frequency when a large block load is suddenly applied, and its depth depends on how quickly the governor and engine respond plus the system's rotational inertia (H constant).
In a diesel prime mover governor system, what is the purpose of the 'speed bias' input signal often provided from a paralleling panel?
Answer: To remotely trim engine speed setpoint for load sharing or synchronization
The speed bias signal allows a paralleling control panel to raise or lower the governor speed setpoint remotely, enabling automatic load sharing and synchronization.
What is the typical overspeed shutdown setpoint for a diesel generator set as a percentage of rated speed?
Answer: 110%
Most diesel generator sets are configured to shut down on overspeed at approximately 110% of rated speed to protect mechanical components.
Which governor type provides the best frequency regulation for critical loads such as hospital or data center applications?
Answer: Electronic isochronous governor
Electronic isochronous governors maintain virtually constant frequency under varying loads, making them ideal for critical applications sensitive to frequency variation.
A Woodward governor is an example of which governor category?
Answer: Hydro-mechanical or electronic governor widely used in industrial generator sets
Woodward governors are hydro-mechanical or electronic governors that are the industry standard for precision speed control in industrial generator sets.
During a load rejection event (sudden loss of connected load), what immediate action does the governor take?
Answer: Reduces fuel delivery to prevent engine overspeed
When load is suddenly lost, the engine would overspeed without intervention, so the governor immediately reduces fuel delivery to bring speed back to rated.