Determination of Equivalent Circuit Parameters
The parameters of the equivalent circuit of a single phase induction can be determined from:-
- Blocked-rotor test
- No-load test
Blocked-rotor test
In this, the rotor is at rest. A low voltage is applied to the stator so that rated current flows in the main winding. The voltage, current, and power input are measured.
- Ze = [Tex]\frac{V_{sc}} {I_{sc}} [/Tex]
Equivalent series resistance Re of the motor, Re = [Tex]\frac{P_{sc}}{I_{sc}^{2}} [/Tex]
Equivalent reactance, Xe = X1m + X2‘
Since leakage reactances X1m and X2‘ cannot be separated therefore, X1m = X2‘
- X1m = 0.5 * (Ze2 – Re2)1/2
No-Load Test
The motor is run without load at rated voltage and rated frequency.
At no load, the slip ‘s’ is very close to zero and [Tex]\frac{R2′}{2s} [/Tex] is very large as compared to [Tex]\frac{X_{M}}{2} [/Tex].
The resistance [Tex]\frac{R2′}{2(2-s)} [/Tex]associated with the backward field is so small as compared to [Tex]\frac{X_{M}}{2} [/Tex].
- X0 = X1m + [Tex]\frac{X_{M}}{2} [/Tex] + X2‘
Since X1m and X2‘ are already known from the blocked rotor test.
Let V0, I0, the denote and P0 denote the voltage, current, and power at the no-load test. Then no-load power factor is
- cosΦ0 = [Tex]\frac{P_{0}}{V_{0}I_{0}} [/Tex]
The no-load impedance is, Z0 = V0/I0
The no-load equivalent reactance is,
X0 = Z0 sinΦ0 = Z0 x (1 – cos2 Φ0 )
Single Phase Induction Motor
A single-phase induction motor is a small-size motor with a fractional-kilowatt rating. They work on the principle of electromagnetic induction to create a rotating magnetic field. It is used in domestic appliances like fans, hair dryers, washing machines, vacuum cleaners, mixers, refrigerators, food processors and kitchen equipment employ these motors.
- Construction of Single-Phase Induction Motor
- Components of Single-Phase Induction Motor
- Operation and Working of Single-Phase Induction Motor
- Application of Single-Phase Induction Motor
- Advantages of Single-Phase Induction Motor
- Disadvantages of Single-Phase Induction Motor
- Solved examples on Single-Phase Induction Motor