EGSA Prime Mover and Governors 4

Question 1

A natural gas engine prime mover uses which type of ignition system, unlike a diesel engine?

Accepted Answer

Spark ignition

Answer

Natural gas engines use spark ignition because natural gas has a higher octane rating and will not self-ignite under diesel compression ratios.

Question 2

What is 'transient frequency dip' in generator performance and what primarily determines its magnitude?

Accepted Answer

A momentary frequency drop upon sudden load application; determined by engine/governor response time and rotating inertia

Answer

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).

Question 3

In a diesel prime mover governor system, what is the purpose of the 'speed bias' input signal often provided from a paralleling panel?

Accepted Answer

To remotely trim engine speed setpoint for load sharing or synchronization

Answer

The speed bias signal allows a paralleling control panel to raise or lower the governor speed setpoint remotely, enabling automatic load sharing and synchronization.

Question 4

What is the typical overspeed shutdown setpoint for a diesel generator set as a percentage of rated speed?

Accepted Answer

110%

Answer

Most diesel generator sets are configured to shut down on overspeed at approximately 110% of rated speed to protect mechanical components.

Question 5

Which governor type provides the best frequency regulation for critical loads such as hospital or data center applications?

Accepted Answer

Electronic isochronous governor

Answer

Electronic isochronous governors maintain virtually constant frequency under varying loads, making them ideal for critical applications sensitive to frequency variation.

(EGSA) Electrical Generating Systems Association Certified Practice Test

(EGSA) Electrical Generating Systems Association Certified Practice Test

EGSA Prime Mover and Governors 4