For higher values of armature, the speed of a DC series motor is
A. Constant.
B. Proportional to armature current.
C. Proportional to the square of armature current.
D. Inversely proportional to armature current.
Answer: A
Share your understanding of this question with the correct explanation.
For higher values of armature current, the speed of a DC series motor is constant.
DC series motors have a speed-torque characteristic that shows a relatively constant speed over a wide range of load torques. This characteristic is due to the inherent design of the motor, where the field winding and armature winding are connected in series.
In a DC series motor, the armature current flows through both the armature winding and the field winding. As the armature current increases, the magnetic field strength produced by the field winding also increases. This leads to a corresponding increase in the motor’s torque output.
However, the increase in armature current does not significantly affect the motor’s speed. The speed of a DC series motor is primarily determined by the supply voltage and the mechanical load torque. As long as the supply voltage remains constant and the load torque does not change significantly, the speed of the motor will remain relatively constant.
Therefore, the correct answer is A: Constant. For higher values of armature current, the speed of a DC series motor remains constant as long as the supply voltage and load torque remain unchanged.