🔍 Key Concepts

• How a current transformer (CT) is used in protection circuits • Purpose of overload current setting and time delay controls in motor protection • How electronic circuits create a trip and alarm signal from sensed current

💭 Think About

• Look at the left side of the diagram: what is being measured or sensed, and how is it brought into the circuit? • Several potentiometers are labeled with current and time delay settings—what kind of device needs both adjustable current and time characteristics? • Follow the signal path from the sensing input to the relay coil (RLA) and trip/alarm contacts—what overall function would that serve in an electrical power system?

✅ Before You Answer

• Identify what the CT input is normally used for on shipboard electrical systems. • Note the presence of trip & alarm contacts on the output and what type of equipment uses such contacts. • Confirm whether an oscillator or function generator would normally include CT input, current setting pots, and a trip relay—eliminate options that don’t match these features.