Final Answer:
The permanent magnet DC motor displays a direct correlation between torque and speed owing to its inherent design. b) Permanent magnet DC motor
Step-by-step explanation:
The permanent magnet DC motor exhibits a linear relationship between torque and speed due to its inherent characteristics. In this motor type, the magnetic field is created by permanent magnets rather than electromagnets, ensuring a fixed magnetic field strength. Consequently, the motor's torque is directly proportional to the current passing through it, resulting in a linear relationship with speed.
The fundamental principle governing this relationship is described by the torque-speed equation:
T = K * Φ * I
Where:
T = Torque
K = Motor constant
Φ = Magnetic flux
I = Current
In a permanent magnet DC motor, Φ remains constant as it's determined by the permanent magnets. Therefore, the torque is directly proportional to the current supplied to the motor. As the speed of the motor is directly linked to the torque, an increase or decrease in current yields a linear change in both torque and speed.(b)
This unique feature of the permanent magnet DC motor makes it suitable for applications where precise control over speed and torque with a linear relationship is required, such as in conveyor systems, robotics, and electric vehicles. Its simplicity, reliability, and linear characteristics make it a preferred choice in various industries where precise control over motor operations is crucial.