MIL-M-3971D, MILITARY SPECIFICATION: METERS, TIME TOTALIZING, NON-HERMETICALLY SEALED, ELECTRICAL: GENERAL SPECIFICATION FOR (12 JUN 1981) [S/S BY MIL-DTL-3971E]

MIL-M-3971D, MILITARY SPECIFICATION: METERS, TIME TOTALIZING, NON-HERMETICALLY SEALED, ELECTRICAL: GENERAL SPECIFICATION FOR (12 JUN 1981) [S/S BY MIL-DTL-3971E]., This specification covers the general requirements for electrically operated non- hermetically sealed meters that automatically measure, and cumulatively register the total operating or idle time of the circuit, machine or system to which connected.