Drivetrain & Transmission Flashcards
7 cards from real LEC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Drivetrain & Transmission flashcards as text
What is the primary function of a locomotive's main generator (alternator) in a diesel-electric drivetrain?
Answer: Convert diesel engine mechanical output to electrical power for traction motors
The main generator converts the diesel engine's mechanical energy into electrical power that feeds the traction motors on each axle.
In a diesel-electric locomotive, what component controls the amount of electrical power delivered to the traction motors?
Answer: The load regulator (throttle control system)
The load regulator adjusts field excitation and generator output to control power delivered to traction motors in response to throttle position.
What happens to wheel slip in a diesel-electric locomotive when tractive effort exceeds the rail-wheel adhesion limit?
Answer: The traction motor speeds up unloaded, causing wheel spin
When adhesion is exceeded, the drive wheels lose traction and spin freely, causing the traction motor to accelerate rapidly without load.
On a six-axle diesel-electric locomotive, how are traction motors typically connected electrically during starting operations?
Answer: Motors grouped in series-parallel combinations for high starting torque
Series-parallel groupings allow high torque at low speed by limiting current through individual motors while maintaining adequate voltage.
What is the purpose of the transition in a diesel-electric locomotive's power circuit?
Answer: To change traction motor connections from series to parallel as speed increases
Transition reconnects traction motors from series to parallel to allow higher speeds while maintaining efficient power utilization.
A locomotive engineer notices the wheel slip indicator activating repeatedly on wet rail. The BEST corrective action is to:
Answer: Apply sand and reduce throttle to restore adhesion
Sanding the rail increases friction at the wheel-rail interface, and reducing throttle lowers tractive effort to within the available adhesion limit.
What is 'creep control' or 'adhesion control' in modern locomotive drivetrains?
Answer: An electronic system that optimizes wheel slip to maximize tractive effort
Adhesion control systems monitor and maintain a small, optimal amount of wheel creep that actually maximizes available tractive force at the rail-wheel interface.