In the RPM formula for a motor, what does P represent?

In the RPM (Revolutions Per Minute) formula for a motor, the variable P represents the number of poles in the motor. The RPM of an induction motor is determined by the formula:

[ \text{RPM} = \frac{120 \times f}{P} ]

where f is the frequency of the electrical supply in hertz (Hz), and P is the number of poles. The number of poles is a critical factor because it directly influences the speed at which the motor operates. Motors with more poles typically run at lower speeds for a given frequency compared to those with fewer poles.

Understanding this relationship is essential for selecting a motor for specific applications, ensuring that the desired speed is achieved based on the electrical supply frequency and the motor's design configuration. The other options do not align with the role of P in the RPM formula, as power, phases, and permissible load pertain to different aspects of motor operation but are not directly related to the calculation of RPM.