Identifying Incorrect Statement: Repulsion-Start Induction Motor

The question asks to identify the statement that is incorrect regarding repulsion-start induction motors. We need to evaluate each option based on the characteristics of this motor type.

• Statement 1: Repulsion-start motors use commutators and brushes. These components require regular maintenance, such as cleaning and brush replacement, and are prone to mechanical wear. Therefore, the statement that it requires more maintenance of the commutator and other mechanical devices is correct.
• Statement 2: The operation of the commutator and brushes, especially during the starting phase and the transition to induction running, can generate audible noise. This statement is considered correct.
• Statement 3: While repulsion-start motors were used, particularly in earlier designs for fractional horsepower applications, they have largely been superseded in many areas by other motor types. Capacitor-start motors and Permanent Split Capacitor (PSC) motors often offer advantages like quieter operation, better efficiency, and simpler starting mechanisms for fractional horsepower ratings. Thus, the claim that repulsion-start motors have replaced capacitor motors in these applications is generally incorrect.
• Statement 4: Reversing the direction of rotation in a repulsion motor typically involves physically shifting the position of the brushes. This process is more complex than reversing the supply connections in a standard induction motor. Therefore, the statement that it is not easily reversed is correct.

The analysis shows that the statement regarding repulsion-start induction motors replacing capacitor motors in fractional horsepower applications is inaccurate.