Answer & Solution
Answer: Option B
Solution:
Regenerative braking: This method is highly efficient and is widely used in elevators. In regenerative braking, the motor acts as a generator, converting the kinetic energy of the elevator into electrical energy, which is then fed back into the power supply. This results in a significant energy-saving benefit while ensuring a smooth and controlled stop.
Why it's preferred for elevators:
Efficiency: Regenerative braking does not waste energy as heat, unlike rheostat braking. It instead recovers the energy and returns it to the system, which is a major advantage in reducing operational costs and improving the system's overall efficiency.
Safety and Reliability: Regenerative braking causes less wear and tear on the motor and other components compared to methods like plugging. It provides a reliable and smooth deceleration, which is critical for the safe operation of elevators.
Comparison with other methods:
Option A: Plugging: This involves reversing the polarity of the motor's voltage, generating a counter-torque that brings the elevator to a stop. While effective, it creates more wear on the motor and is not ideal for frequent use like in elevators.
Option C: Rheostat braking: This method adds resistance to the motor circuit to dissipate energy as heat. While simple, it is less efficient because it wastes energy and is not as effective as regenerative braking in terms of energy recovery.
Therefore, regenerative braking is the most efficient, safe, and reliable method for elevators, making it the best choice for frequent and smooth braking in such systems.
