GB1204111A - Improvements in or relating to consumers electric supply meters - Google Patents

Abstract

1,204,111. Coin-freed meter; counting apparatus. LONDON ELECTRICITY BOARD and A. J. BAGGOTT. 23 Aug., 1967 [26 May, 1966], No. 23692/66. Headings G4D and G4V [Also in Division G1] An electricity metering installation includes a plug-in meter which provides an electric output in the form of signals which may operate a remote indicator and/or a coin or token operated prepayment unit. Associated with the meter is an electrically operable contactor unit, e.g. a solenoid-operated or thermally operated or solid state switch. This switch can be operated to interrupt the electricity supply either by control signals, e.g. from the prepayment unit or an off-peak tariff control timer, or automatically on disconnection of one of the elements of the installation, e.g. the prepayment unit. Fig. 2 shows such an installation in which the plug-in meter 13 controls the operation of an impulse generating switch 17 which is connected to a repeat register 22 operated by the impulses and also to a prepayment unit 19 which is similarly operated. In the prepayment unit coins or tokens-which may be paper tokensestablish a credit of electric units, a switch 20 being operated when the credit is used up. This switch controls the operation of the switch 21 of the meter's associated contactor unit 14 to interrupt the supply. In a modification (Fig- 5, not shown) the prepayment unit has an over. ride control which when operated establishes an unpaid-for credit, e.g. to the value of one coin or token. When this credit has been used, no further electricity can be obtained until a further token is inserted, but insertion of such further token is arranged to reset the override control. The unit 23 in Fig. 2 is a device to cut off the supply in accordance with tariff requirements-e.g. it may be a timer controlling an off-peak tariff, or a load-sensitive device, or a device operated by control signals from the supply authority. If prepayment is not required unit 19 can be removed, and this automatically opens switch 14. A short circuiting link replacing it, i.e. restoring the connection between meter 13 and contactor unit 14, will then convert the installation from prepayment to credit metering without the necessity to replace the meter. Fig. 4 (not shown) depicts an installation in which the supply energizes the primary winding of a transformer and the plug-in meter is connected to the secondary winding. This makes it possible to remove the meter without interupting the supply, but the arrangement can be such that unauthorized removal would break a signal circuit and, in response, open the contactor to disconnect the supply.