標準號：IS 722 Pt.3-1977
發布日期：1977/11/1 12:00:00
實施日期：1999/12/31 12:00:00
適用范圍：1.1 This standard ( Part III ) specifies the requirements and tests for the following types of watthour meters of an accuracy class 2:a) 3-phase whole current and transformer operated watthour meters for unbalanced load for use in 3-phase 3-wire and 3-phase 4-wire supplies, andb) 1-phase transformer operated watthour meters for use in 1-phase 2-wire supplies.Note — In case of 3-phase watthour meters operated in conjunction with maximum demand indicators, additional requirements of IS : 8530-1977* shall also apply.1.2 It does not apply to watthour meters in which the principle of measurement requires balanced conditions of load or supply.