Virtual Labs

Tools

To determine positive sequence, negative sequence and zero sequence reactances of an alternator.

Observations

Table 1 - Open Circuit Test

S.No.	Voltage (V)	Field Current (A)	Speed (rpm)
1.	.	.	.
2.	.	.	.
3.	.	.	.
.	.	.	.
.	.	.	.
n	.	.	.

Table 2 - Short Circuit Test

S.No.	Armature Current (A)	Field Current (A)	Speed (rpm)
1.	.	.	.
2.	.	.	.
3.	.	.	.
.	.	.	.
.	.	.	.
n	.	.	.

Table 3 - Determination of X₂

S.No.	Voltage (V)	Current (A)	Power (W)	Z₂ (Ω)	X₂ (Ω)
1.	.	.	.	.	.
2.	.	.	.	.	.
3.	.	.	.	.	.
.	.	.	.	.	.
.	.	.	.	.	.
n	.	.	.	.	.

Table 4 - Determination of X₀

S.No.	Voltage (V)	Current (A)	Speed (rpm)	X₀ (Ω)
1.	.	.	.	.
2.	.	.	.	.
3.	.	.	.	.
.	.	.	.	.
.	.	.	.	.
n	.	.	.	.

Formulas Summary

Reactance	Formula	Test
X₁	X₁ = E / I_sc	Open Circuit + Short Circuit Test
Z₂	Z₂ = V_os / (3 × I_sc)	Two-phase short circuit
X₂	X₂ = Z₂ × sin φ, where φ = cos⁻¹(P / (V_sc × I_sc))	Two-phase short circuit
X₀	X₀ = 3 × (V₀ / I₀)	All three phases in parallel

Important Notes

For X₁ test: Run machine at rated speed, vary field current, record OCC and SCC data.
For X₂ test: Short circuit two phases, keep excitation low, measure voltage, current, and power.
For X₀ test: Connect all three phases in parallel, apply reduced single-phase voltage, short the rotor field winding.
Ensure all readings are taken within machine ratings to avoid damage.

Fill in the observed values in place of "." for each table during the experiment.