LEC Mechanical and Electrical Systems

Question 1

What is the function of the locomotive's alternator?

Accepted Answer

Answer

In a diesel-electric locomotive, the diesel engine drives a main generator or alternator. This alternator's primary function is to convert the mechanical energy produced by the diesel engine into electrical energy. This electrical energy then powers the traction motors, which in turn drive the wheels, moving the train.

Question 2

How does the locomotive's diesel engine contribute to the mechanical systems?

Accepted Answer

Answer

The diesel engine is the heart of a diesel-electric locomotive, serving as the prime mover. It generates mechanical power by burning diesel fuel, which then drives a main generator or alternator. This generated electricity is subsequently supplied to the traction motors, which convert it back into mechanical power to turn the wheels and propel the train.

Question 3

What is the purpose of the locomotive's traction motors?

Accepted Answer

Answer

Traction motors are electric motors located on the axles of a diesel-electric locomotive. Their essential function is to convert the electrical energy supplied by the main generator/alternator into mechanical rotational force. This mechanical force is then transmitted to the wheels, directly propelling the train along the tracks.

Question 4

Why is the electrical system in a locomotive important for its operation?

Accepted Answer

Answer

Beyond powering the traction motors, the electrical system in a locomotive is crucial for operating numerous auxiliary and essential systems. This includes lighting for visibility, communication radios for dispatch and crew coordination, control systems, and safety devices, all of which are vital for safe and efficient train operation.

Question 5

How do the mechanical brakes work on a locomotive?

Accepted Answer

Answer

Locomotive mechanical brakes, commonly known as air brakes, operate by using compressed air to actuate brake cylinders. This compressed air forces brake shoes or pads against the wheels or brake discs, generating friction that slows and eventually stops the train. This system is distributed throughout the entire train, with each car having its own air brake components.

(LEC) Locomotive Engineer Certification Practice Test

(LEC) Locomotive Engineer Certification Practice Test

LEC Mechanical and Electrical Systems