Motors Book - Chapter 5

Explanation
A stator motor is an electric motor that uses the principles of mutual induction to develop current and torque in the rotor. The stator is the stationary part of the motor that contains the coils of wire, which when energized, create a rotating magnetic field. This rotating magnetic field induces a current and torque in the rotor, causing it to rotate. Therefore, the stator plays a crucial role in the operation of the motor by providing the necessary magnetic field for the generation of current and torque.

Explanation
The stator is the stationary part of an AC motor. It is responsible for generating a rotating magnetic field that interacts with the rotor to produce mechanical motion. Unlike the rotor, which rotates, the stator remains fixed in place. It consists of a core made of laminated iron and copper windings that carry the electrical current. The stator's primary function is to provide the necessary magnetic field for the motor to operate efficiently.

Explanation
The stator windings consist of coils of copper wire placed in slots 120 electrical degrees apart. These windings are an essential part of the stator, which is the stationary component of an electric motor or generator. The windings are responsible for generating the electromagnetic field necessary for the motor or generator to function. By placing the coils in slots and spacing them 120 degrees apart, the windings ensure a balanced and efficient distribution of the electromagnetic forces within the stator.

Explanation
The correct answer is "rotor." A rotor is the rotating part of an AC motor. It is typically made up of a laminated iron core with conductive windings that carry the electric current, creating a magnetic field. The rotor is responsible for converting electrical energy into mechanical energy by rotating within the stator, which is the stationary part of the motor.

Explanation
A shorting ring, also known as a conducting ring, is a metal ring that is used to establish electrical connections between the bars of a squirrel-cage rotor. This ring is typically placed at the end of the cage frame and helps in improving the performance and efficiency of the rotor. By creating a low-resistance path, the conducting ring allows for the flow of current and helps in reducing losses and improving the overall operation of the rotor.

Explanation
Option A, "Motor Design A," is the correct answer because it is stated that this design has normal starting torque and normal starting current. This implies that Motor Design A does not have any exceptional or abnormal characteristics in terms of its starting torque and current.

Explanation
The correct answer is C. The explanation for this is that motor design C has high starting torque and low starting current. Starting torque refers to the torque produced by the motor at startup, which is important for overcoming inertia and starting the motor. A high starting torque means that the motor can quickly and effectively start up heavy loads. Starting current refers to the current drawn by the motor at startup. A low starting current means that the motor requires less initial current to start up, which can be beneficial in terms of energy efficiency and reducing stress on the electrical system.

Explanation
The correct answer is conducting bars. When current flows through the conducting bars in the rotor, it generates a magnetic field around them. This magnetic field interacts with the stator windings to produce the necessary torque for the motor to operate. The conducting bars act as a pathway for the current to flow, allowing for the creation of the magnetic field.

Explanation
When a current flows through a wire in the presence of a magnetic field, a force is exerted on the wire. This force causes the wire to rotate around an axis, resulting in the creation of torque. Therefore, the combined magnetic field and current flow interact to create torque.

Explanation
In an induction motor, the field windings are located in the stator and the rotors are designed to interact with the rotating stator magnetic field. The field windings are responsible for creating the magnetic field in the stator, which induces a current in the rotor bars and creates a torque that drives the motor. The conductor bars, shorting bars, and squirrel-cage bars are all components of the rotor, but they do not generate the magnetic field necessary for the motor operation.