Quiz on Contactors and Magnetic Motor Starters

What was the first device used to start and stop electric motors?

• Knife switch

• Magnetic contactor

• Manual starter

• Circuit breaker

What is the function of a manual contactor?

• To step down voltage

• To provide overload protection

• To energize or de-energize a load

• To extinguish electrical arcs

What is the purpose of a heater coil in a manual starter?

• To act as a solenoid

• To provide additional power

• To cool down the motor

• To monitor excessive current and heat

Which of the following is NOT a criterion for selecting AC manual starters?

• Color of the enclosure

• Voltage

• Number of poles

• Phasing

What is the principal operating mechanism for magnetic contactors?

• Ratchet wheel

• Heater coil

• Solenoid action

• Knife switch

What is the purpose of a step-down control transformer in a control circuit?

• To convert AC to DC

• To maintain the voltage

• To decrease the voltage

• To increase the voltage

What does a magnetic motor starter include that a basic contactor does not?

• Overload protection

• Double brake contacts

• Manual reset button

• AC coil

What is the role of a bimetallic strip in a magnetic motor starter?

• To separate contacts during overload

• To act as a solenoid

• To provide additional power

• To cool down the motor

Which device combines a thermistor, solid-state relay, and contactor?

• Circuit breaker

• Manual starter

• Thermistor overload device

• Magnetic contactor

What is the first device checked when troubleshooting a circuit that does not work?

• Heater coil

• Transformer

• Contactor or motor starter

• Circuit breaker