Consider the following statements regarding ac drives: 1. For the same kW rating, ac motors are 20% to 40% light weight as compared to dc motors. 2. The ac motors are more expensive as compared to same kW rating dc motors. 3. The ac motors have low maintenance as compared to dc motors. Which of the above statements are correct?

Consider the following statements regarding ac drives: 1. For the same kW rating, ac motors are 20% to 40% light weight as compared to dc motors. 2. The ac motors are more expensive as compared to same kW rating dc motors. 3. The ac motors have low maintenance as compared to dc motors. Which of the above statements are correct? Correct Answer 1 and 3 only

Advantages of ac drives:

• For the same rating, ac motors are lighter in weight as compared to dc motors
• AC motors require low maintenance as compared to dc motors
• AC motors are less expensive as compared to equivalent dc motors
• AC motors can work in hazardous areas like chemical, petrochemical etc. whereas dc motors are unsuitable for such environments because of commutator sparking

Disadvantages of ac drives:

• Power converters for the control of ac motors are more complex
• Power converters for ac drives are more expensive
• Power converters for ac drives generate harmonics in the supply system and load circuit. As a result, ac motors et derated.