This paper presents a simple method for determining synchronous machine quantities: d- and q-axes time constants and reactances. This method determines them only by drawing additional lines in the frequency characteristics of operational impedances. A new systematic drawing strategy for determining transient/subtransient open-circuit time constants and the d-axis transient reactance is proposed. The frequency characteristics of operational impedances are obtained by the standstill DC test using a small DC power supply. Since the rotational test becomes unnecessary, the proposed method is suitable for tests in a factory. The validity of the proposed method was demonstrated with a numerical calculation example on a large-capacity machine (800MVA, 25kV, 2 poles, 60Hz) and an implementation test on a small-capacity machine (10kVA, 200V, 31.9A, 4 poles, 50Hz).