The rotor current frequency in an induction motor operating at 50 Hz, with 4% slip is

Rotor Current Frequency in an Induction Motor

Definition: The rotor current frequency in an induction motor is the frequency of the current induced in the rotor circuit, which depends on the slip of the motor and the supply frequency. It is an essential parameter in understanding the performance of an induction motor, as it determines the relative motion between the stator's rotating magnetic field and the rotor.

Slip Formula:

S = ((N_s - N_r) / N_s) × 100

Where:

• N_s = Synchronous speed of the stator's magnetic field (in revolutions per minute, RPM).
• N_r = Rotor speed (in RPM).

The slip determines the frequency of the rotor current (f_r), which is given by the relationship:

Rotor Current Frequency Formula:

f_r = S × f_s

Where:

• f_r = Rotor current frequency (in Hz).
• S = Slip (expressed as a decimal).
• f_s = Supply frequency (in Hz).

Calculation:

Given the supply frequency (f_s) is 50 Hz and the slip (S) is 4% (or 0.04 in decimal form), the rotor current frequency (f_r) can be calculated as follows:

f_r = S × f_s

f_r = 0.04 × 50

f_r = 2 Hz

Therefore, the rotor current frequency is 2 Hz.