Electricity: Mastering Motor Control Circuits

What is the primary purpose of a motor control circuit?

• To increase the speed of the motor

• To start, stop, and regulate the motor's operation

• To convert AC to DC

• To reduce the motor's size

If a motor has a voltage rating of 240V and a current rating of 10A, what is the power consumption of the motor?

• 1200W

• 2400W

• 4800W

• 600W

Which component in a motor control circuit is used to protect the motor from overload?

• Resistor

• Capacitor

• Circuit breaker

• Transformer

A motor has a resistance of 5 ohms and is connected to a 20V power supply. What is the current flowing through the motor?

• 2A

• 4A

• 5A

• 6A

Which of the following is NOT typically found in a motor specification sheet?

• Voltage rating

• Current rating

• Color of the motor

• Power factor

Using Ohm's Law, calculate the voltage across a motor with a resistance of 10 ohms and a current of 3A.

• 10V

• 20V

• 30V

• 40V

In a motor control circuit diagram, what does a dashed line typically represent?

• A physical connection

• A mechanical linkage

• An electrical short

• A broken circuit

What is the first step in troubleshooting a motor that won't start?

• Replace the motor

• Check the power supply

• Inspect the motor windings

• Test the motor's speed

If a motor is drawing more current than its rated value, what could be a possible cause?

• Low supply voltage

• High supply voltage

• Mechanical overload

• Open circuit

What is the function of a contactor in a motor control circuit?

• To increase voltage

• To switch the motor on and off

• To reduce current

• To convert AC to DC