Abstract: An A.C. electric power usage measuring and display system using microcomputer based digital processing. Power usage pulses optically sensed from a watthour meter rotary disc and time pulses sensed from the 60 Hz A.C. power line are input to a microprocessor that is programmed to calculate and display the day of the week 1 to 7, the time of day on a 24-hour clock basis, the total watthours and kilowatthours since the start of a billing period on a decimal basis, the peak interval watthours and kilowatthours on a decimal basis, the peak interval start time and end time on a 24-hour clock basis for a peak interval of predetermined time, the peak power demand in kilowatts on a decimal basis, the day of the peak demand on a weekly 1 to 7 basis, the time of the peak demand on a 24-hour clock basis, and the present demand in kilowatts on a decimal basis.

Abstract: A hydrostatic transmission for accelerating, driving and braking a high inertia load, such as the swing mechanism of a power shovel or crane, includes an engine-driven swashplate-type variable displacement constant speed reversible main hydraulic pump coupled in a closed loop circuit to a swashplate-type fixed displacement variable speed reversible hydraulic motor. A pair of control lever operated pilot pressure modulated pump displacement control valves selectively direct control fluid from an engine-driven fixed displacement constant speed charge pump to the stroking pistons of the servo control cylinders on the main pump to thereby control motor direction and speed. The charge pump also supplies replenishing fluid to the main pump/motor circuit through replenishing check valves.