In slip test on a 3-phase alternator, the maximum and minimum voltage per phase are *V*_{1} and *V*_{2} respectively whereas the maximum and minimum phase currents are found to be *I*_{1} and *I*_{2} respectively. The value of the d-axis synchronous reactance *x*_{d} and q-axis synchronous reactance *x*_{q} are determined as

1. \({x_d} = \frac{{{V_1}}}{{{I_1}}},\;{x_q} = \frac{{{V_2}}}{{{I_2}}}\)

2. \({x_d} = \frac{{{V_1}}}{{{I_2}}},\;{x_q} = \frac{{{V_2}}}{{{I_1}}}\)

3. \({x_d} = \frac{{{V_1}}}{{\left( {{I_{1 - }}{I_2}} \right)}},\;{x_q} = \frac{{{V_2}}}{{({I_1} + {I_2})}}\)

4. \({x_d} = \frac{{({V_1} + {V_2})}}{{({I_1} - {I_2})}},\;{x_q} = \frac{{\left( {{V_1} - {V_2}} \right)}}{{\left( {{I_2} + {I_1}} \right)}}\)