The electric fan rotates at 6 due to the design of the motor within the fan. The motor, typically an induction motor, converts electrical energy into mechanical energy, causing the fan blades to rotate. The speed of rotation, often referred to as RPM (Revolutions Per Minute), is determined by the motor's design and the voltage applied to it.

The reason for the specific rotation speed of 6 RPM can be attributed to several factors. Firstly, the design of the motor includes a winding configuration that determines the number of poles and the magnetic field strength. These factors influence the speed at which the motor can rotate. Secondly, the voltage supplied to the motor affects its speed; a higher voltage generally results in a faster rotation speed. In the case of a 6 RPM fan, the motor is designed to operate at this specific speed, which is often suitable for low-intensity cooling or air circulation tasks.

According to data from the National Electrical Manufacturers Association (NEMA), the standard voltage for residential electric fans in the United States is 120V. The speed of the fan is directly proportional to the voltage applied to the motor. For example, a fan designed to operate at 6 RPM will typically have a winding configuration that allows it to achieve this speed when powered by 120V. This design ensures that the fan operates efficiently and safely for its intended use.

In summary, the electric fan rotates at 6 RPM due to the motor's design, which includes a winding configuration and voltage requirements that allow for this specific speed. This design ensures the fan operates effectively for its intended purpose, such as providing low-intensity cooling or air circulation.