A large series motor is never started without some mechanical on it because otherwise it will
A. Produce sparking at brushes.
B. Open fuse or circuit breaker.
C. Draw too much current.
D. Develop excessive speed and damage itself.
Answer: D
Share your understanding of this question with the correct explanation.
A large series motor is never started without some mechanical load on it because otherwise, it will develop excessive speed and damage itself.
A series motor is designed to provide high starting torque and is commonly used in applications where high torque is required, such as in traction systems and heavy machinery. The torque output of a series motor is directly proportional to the square of the armature current.
When a series motor starts without any mechanical load (or with a very light load), the load torque is low or negligible. As a result, the torque produced by the motor exceeds the load torque, causing the motor to accelerate rapidly. Without the counteracting force of the load, the speed of the motor increases to potentially dangerous levels.
The excessive speed can lead to various issues, such as increased wear and tear on the motor’s components, damage to the mechanical system driven by the motor, and even catastrophic failure of the motor itself.
Therefore, it is essential to always have some mechanical load on a large series motor during startup to prevent it from developing excessive speed and causing damage.