Electrical Engineering XYZ MCQs
Which type of motors are preferred in lifts:
- DC shunt motors
- DC compound motors
- DC series motors
- None of the above
Correct answer: 2. DC compound motors
Explanation: The preferred type of motors for lifts is “DC compound motors.” Here’s why:
- Constant Speed: Lifts require a consistent speed for smooth operation. DC compound motors are well-suited for this because they offer relatively constant speed regardless of the load variation. This is crucial for ensuring passenger comfort and safety.
- Torque Characteristics: DC compound motors provide both good starting torque and speed regulation. Lifts often need to start from a standstill with a heavy load, and the torque characteristics of compound motors make them suitable for this task.
- Control: DC compound motors offer excellent control over speed and direction, which is essential for precise positioning of the lift car at different floors.
- Reliability: These motors are known for their reliability and durability, making them suitable for the continuous operation required in lift systems.
In contrast:
- DC shunt motors might lack the necessary torque for lifting heavy loads, and they may not provide adequate speed regulation.
- DC series motors might provide high starting torque, but they lack the speed regulation needed for smooth operation and may not offer the level of control required for precise positioning in lift systems.