What is the primary function of the field frame in a DC motor?

What is the primary function of the field frame in a DC motor?

• A. Rectify AC
• B. Support rotor mechanically
• C. House the brushes
• D. Provide the magnetic field for motor operation

Answer: (D)

The field frame provides the magnetic field that the motor needs to produce torque. In a DC motor, the rotor current interacts with a magnetic flux to develop force and cause rotation. The field frame either contains the field windings that generate that flux or carries permanent magnets that supply the flux, and it forms the magnetic circuit with the yoke and pole pieces. Without this magnetic field, the armature current would have nothing to interact with, so no torque would be produced. Other tasks like rectifying AC, supporting the rotor mechanically, or housing the brushes are handled by other parts of the motor, not the field frame.

The field frame provides the magnetic field that the motor needs to produce torque. In a DC motor, the rotor current interacts with a magnetic flux to develop force and cause rotation. The field frame either contains the field windings that generate that flux or carries permanent magnets that supply the flux, and it forms the magnetic circuit with the yoke and pole pieces. Without this magnetic field, the armature current would have nothing to interact with, so no torque would be produced. Other tasks like rectifying AC, supporting the rotor mechanically, or housing the brushes are handled by other parts of the motor, not the field frame.