Quiz on Electrical Relays and Transducers

What is the primary purpose of a protective relay?

• To supply power to the circuit

• To sense abnormal conditions and trip the circuit breaker

• To maintain voltage levels

• To provide backup power

Which of the following is a type of relay?

• Definite time relay

• Inductive relay

• Capacitive relay

• Mechanical relay

What does an electromechanical relay use to operate its contacts?

• Solid-state switches

• Electromagnet

• Hydraulic systems

• Pneumatic systems

Which relay compares the primary and secondary currents of a transformer?

• Voltage relay

• Differential relay

• Frequency relay

• Backup relay

What is the main purpose of a contactor?

• To provide overload protection

• To control high current loads

• To regulate voltage

• To measure current

What type of circuit breaker uses SF6 gas for arc extinguishing?

• Bulk oil circuit breaker

• Air blast circuit breaker

• SF6 circuit breaker

• Vacuum circuit breaker

What is the key disadvantage of air blast circuit breakers?

• High maintenance cost

• Fire hazard

• High noise during operation

• Slow operation

Which relay type does NOT have movable contacts?

• Electromechanical relay

• Solid-state relay

• Thermal relay

• Differential relay

What is the purpose of a free-wheeling or flyback diode in a relay circuit?

• To amplify the signal

• To suppress back EMF

• To increase relay speed

• To reduce current flow

In relay timers, what does an ON-delay relay do?

• Turns on immediately

• Delays turning on after the coil is energized

• Delays turning off

• Turns off immediately