Marine Technician Electrical & Electronics Flashcards

What is the purpose of a marine alternator's voltage regulator?

Answer: To maintain a constant output voltage regardless of engine RPM

The voltage regulator keeps alternator output at a stable voltage (typically 13.8–14.4V) across varying engine speeds.

A marine VHF radio suddenly displays 'LOW VOLTAGE' during operation. The most likely cause is:

Answer: Insufficient battery charge or poor wiring connections

Low voltage warnings on marine electronics typically indicate battery depletion or high-resistance connections in the supply circuit.

Which wire color is standardized for DC negative (ground) in ABYC marine wiring?

Answer: Black or yellow

ABYC standards designate black or yellow as the color for DC negative conductors in marine electrical systems.

What does a marine GFCI (Ground Fault Circuit Interrupter) protect against?

Answer: Electric shock by detecting small current leakage to ground

A GFCI monitors the difference in current between hot and neutral conductors, tripping when leakage current (as low as 4–6 mA) flows to ground.

On a marine depth sounder, the transducer sends and receives which type of energy?

Answer: Ultrasonic sound waves

Depth sounders use ultrasonic (high-frequency sound) pulses that travel through water and reflect off the bottom to calculate depth.

Why should marine electrical wire be tinned (tin-coated) rather than bare copper?

Answer: Tinning prevents corrosion in the marine environment

Tinning copper strands protects against oxidation and corrosion caused by the salt-air and humidity typical in marine environments.

A bilge pump float switch that is stuck in the 'ON' position will:

Answer: Run the pump continuously, potentially draining the battery

A stuck-closed float switch energizes the pump relay continuously, running the pump until the battery is discharged.