a) The power consumed by the motor is given as 0.75 kW. We can calculate the current drawn by using the formula:
Power (P) = Voltage (V) x Current (I) x Power Factor (PF)
Given that the power factor is unity, the formula simplifies to:
P = V x I
0.75 kW = 220 V x I
I = 0.75 kW / 220 V
I ≈ 0.0034 kA (kiloamperes)
Therefore, the current drawn by the motor is approximately 0.0034 kA.
b) Since the power factor is unity, the phase angle (θ) is 0 degrees.
Therefore, the motor is operating at a phase angle of 0 degrees.
c) The reactive power (Q) can be calculated using the formula:
Q = √(Apparent Power (S)^2 - Active Power (P)^2)
Given that the power factor is unity, the apparent power (S) is equal to the active power (P).
Q = √(0.75 kW)^2 - (0.75 kW)^2
Q = √(0.75)^2 - (0.75)^2
Q = √0.5625 - 0.5625
Q ≈ √0 - 0.5625
Q ≈ 0 - 0.5625
Therefore, the reactive power of the motor is approximately -0.5625 kVA (kilovolt-ampere) or kVAR (kilovolt-ampere reactive). The negative sign indicates that the reactive power is capacitive.
A single-phase motor draws 0,75 kW from a 220V supply. If the motor is operating at unity power factor, calculate:
a) The current drawn by the motor
b) The phase angle at which the motor is operating
c) the reactive power of the motor
1 answer
1 answer