DC Motor Speed Control - From Basic to Breakthroughs

Which of the following is a traditional method for controlling the speed of a DC motor?

• Using an inverter

• Adding resistance in the armature circuit

• Using a thyristor-based chopper

• Changing the polarity of the motor

What effect does increasing the armature voltage have on the speed of a DC motor?

• It decreases the motor speed

• It increases the motor speed

• It has no effect on the motor speed

• It reverses the motor direction

In a DC shunt motor, speed is primarily controlled by adjusting which of the following?

• The magnetic field strength

• The rotor resistance

• The load torque
  

• The supply voltage to the field windings

What is the primary advantage of using chopper control in DC motor speed regulation?

• Lower cost

• Increased mechanical reliability

• High efficiency and precise control

• Simpler design compared to traditional methods

In separately excited DC motors, how is the field flux controlled?

• By varying the load resistance

• By changing the field current

• By altering the armature voltage

• By adjusting the motor’s mechanical load

Which control method is best suited for large variations in DC motor speed while maintaining high efficiency?

• Field flux control

• Armature resistance control

• Chopper control

• Mechanical load adjustment

When controlling the speed of a DC motor by adding resistance to the armature circuit, what happens to the motor’s torque?

• Torque increases

• Torque remains constant

• Torque decreases

• Torque becomes unstable

Thyristor-based speed control for DC motors is commonly used because it provides:

• High starting torque

• Smooth, stepless speed control

• Low efficiency in high-torque applications

• Constant speed control only

Which of the following is a disadvantage of armature resistance control for DC motors?

• It leads to a decrease in efficiency

• It offers high torque at low speeds

• It provides smooth and continuous speed control

• It reduces motor size and cost

What happens when you reduce the field current in a separately excited DC motor?

• Motor speed decreases

• Motor speed increases

• Motor torque increases

• Motor efficiency drops significantly