How many types are the rotor slots distinguished into?

Rotor slots, particularly in the context of electric motors, are distinguished into several types based on their shapes, configurations, and applications. However, providing a specific number is somewhat challenging due to variations in classification across different sources and applications. In broad terms, rotor slots can be classified into the following categories:

1. Semi-closed Slots: These are often used in the rotors of induction motors. They help in reducing the rotor’s reluctance, which in turn improves the motor’s efficiency.

2. Closed Slots: These slots have a narrow opening at the top. They are used to reduce the slot harmonics and consequently the overall noise and losses in the motor. However, winding these slots can be more challenging due to the limited space for inserting the winding coils.

3. Open Slots: These are easier for winding coil insertion due to the wider openings. They’re typically used in motors where manufacturing cost and ease of assembly are significant considerations. However, they might not be as efficient in controlling harmonics as the closed or semi-closed slots.

4. Parallel Slots: These slots are aligned parallel to the shaft and are typical for certain types of rotors.

5. Skewed Slots: The slots are slightly angled relative to the axis of the shaft. This skewing helps in reducing magnetic locking or cogging between the stator and rotor, resulting in smoother motor operations.

6. Deep Bar Slots: These are used in some rotor designs to achieve certain performance characteristics related