... -wire, 3-phase 4-wire, single-phase mode 3) V, A, W, VA, VAR, KWh, PF, Hz measurement 4) Double ... time and select tested signal be power supply for the clamp at one time, the instrument can measurement for long ... : automatic (when harmonic is serious, it is better to use manual settings for testing frequency so as to assure the ... voltage, current: 45 Hz ~ 65 Hz Three Phase Digital Power Clamp Meter