Patent GB-1360318-A (GB)
Title: Electric -power measuring arrangements for tariff determination
IPC: G01R21/133
Filed: 1972-07-11
Abstract: 1360318 Electricity metering apparatus; counting apparatus LANDIS & GYR AG 11 July 1972 [20 July 1971] 32300/72 Headings G4A G4D and G4H In an electricity metering system a register 2 receives pulses from a conventional meter 1 by way of a converter 3 whose output/input ratio is dependant upon the value of the input whereby the register receives more pulses for the same increments of electricity the higher is the maximum demand. The meter 1 may be a mechanical device operating a contact once for each increment of electricity or an electronic device (not described). In Fig. 2 the converter comprises a binary counter 15 which is reset to zero after each meter pulse by a monostable delay 19. Thereafter the counter 15 fills from a low speed clockpulse generator 11 through AND-gate 12 and OR-gate 13. If the counter fills before the next meter pulse it closes an AND-gate 4 so that the next pulse has no effect except to reset the counter. In this case, i.e. with a low rate of meter pulses, the register 2 receives no input. If the demand rises so that the next pulse arrives before the counter is full, that pulse resets a bi-stable 6 closing gate 12 and opening another gate 9. The counter 15 then receives pulses from a high speed clock 8 so that it fills rapidly and then resets the bi-stable 6 by input 17. The number of pulses to fill the counter 15 is also fed to the register 2, the number depending on the rate of the meter pulses. In Fig. 3, the converter comprises a differential gear 22 one input of which is driven constantly by a synchronous motor 24 and the other by a stepping motor 26 receiving the meter pulses. The output shaft 27 drives the register 2 through a lost motion drive 31, 32 and a freewheeling gear 33, 34. If the stepping motor 26 advances the shaft 27 less than the synchronous motor 24 drives it back, a gear 30 moves backwards, the arm 32 engaging one side of arm 31 and the motion is lost in the free wheeling mechanism 33, 34. If however demand increases and the stepping motor drive is greatest the arm 32 engages the other side of arm 31 and pawl 34 drives gear 33 forward to advance the register 2. The ammount by which the register 2 is advanced for each meter pulse is again dependant on the rate of the meter pulses. A non-linear relationship between the input to the register 2 and the rate of the meter pulses can be produced by varying the rate of oscillator 8 or synchronous motor 24 between meter pulses. A more complex mechanical converter (Fig. 5, net shown) is described for a meter 1 having change-over contacts. An electronic converter (Fig. 6, not shown) feeds to register 2 a number of pulses proportional to [(1/T)-(1/T 0 )]<SP>2</SP> for every meter pulse, where T is the period between successive pulses and T 9  is a reference period (respresented in Fig. 2 by the time to fill counter 15 from clock 11). In this arrangement a further register (88) records the number pulses received while electricity is being consumed above a reference rate. Another arrangement (Fig. 7, not shown) has registers (99, 102) corresponding to 2, (88) for recording similar values below the reference rate and also a device recording the greatest mean power over previous measuring periods. In Fig. 8 a capacitor 103 is charged to a fixed voltage after each meter pulse and is then discharged steadily through 104. The remaining charge on receipt of the next meter pulse is fed to an analogue to digital converter 109 feeding the register 2.