Patent GB-534878-A (GB)
Title: Improvements in and relating to electric load control systems
IPC: H02J13/00
Filed: 1939-11-13
Abstract: 534,878. Prepayment electricity meters with price-changing mechanisms. SCHILLER, P. Nov. 13, 1939, No. 29942. [Class 27] [Also in Group XXXVI] Price-changing mechanism; automatic.-The consumer may override a remote control by the electricity supply undertaking of the load taken by his installation, and his consumption during periods of such overriding control is registered in a different manner. Fig. 1 shows a system having load control devices according to Specification 526,881, [Group XXXVI]. The meter shaft 2 drives, through gearing 5, 6, 9, 10, a rocking shaft 11 carrying a pinion 15 which can be brought into engagement with either of two gear-wheels 16, 17 by raising or lowering a bar 13. The shaft 2 also drives, through gearing 7, 8, 23, 24, one sun-wheel 25 of a differential gear, the other sun-wheel 26 of which is driven through gearing 27, 30 and a pinion 34 on a rocking shaft 31 from either of two gearwheels 35, 44 with which the pinion 34 may be brought into engagement by raising or lowering a bar 33. The planet pinion 28 rotates a shaft 29 which carries a gear-wheel 46 driving a gear-wheel 47. This carries an arm 48 which co-operates with a leaf spring 49. The gearwheel 35 is driven from motor 43 through friction gear 38, 39. The friction wheel 38 is moved along its shaft 40 by remote control means so as to vary the speed of the sunwheel 26 between a maximum and a minimum value. The gear-wheel 44 is driven from the motor 43 through gearing 41, 42, 45 such that, when the pinion 34 engages the wheel 44, the sun-wheel 26 is driven at the same speed as when driven through the friction gear set to its maximum speed. In the position shown the leaf spring 49 engages a contact 55 and short circuits a relay coil 56, which closes its contacts 58 and energises a relay 53 which periodically disconnects and reconnects the controlled load 60. The pinion 15 engages the gear wheel 16 and drives the meter counting train 20 so as indicate actual units consumed. Modification of the control is effected by turning a hand lever 62 from the full-line to the dottedline position, thereby rocking a lever 14 so as to lower the bar 33. The pinion 34 then engages the gear-wheel 44 and the pinion 15 engages the gear-wheel 17. The meter gearing is thereby changed so as to register a pre-determined multiple of the units consumed. A signal lamp 67 is simultaneously put in circuit by contacts 68. 69. The meter may alternatively register the consumption under each condition on separate counters, or the total consumption may be registered on one counter and the consumption under modified load control on a separate counter. In a modification, the load control may be completely suspended and the consumption taken in excess of the setting is registered separately. The meter and the load control devices may be arranged separately as shown in Fig. 5. The control lever 62 changes the meter pinion 15 from one train to the other and 'also actuates a contact spring 68 which when engaging contact 69 closes the circuit of the pilot lamp 67, and when engaging contact 110 closes the circuit of the load control device. This comprises a bi-metallic strip 113 secured to a block 114 at one end and carrying a pin 115 at its other end. The block 114 is pivoted at 117 and carries a second bi-metallic strip 116 for temperature compensation. The strip 113 is heated by a coil 119, carrying the load current, and a second coil 120 connected across the supply terminals in series with a variable resistance 121 and the contacts 68, 110. The resistance 121 is adjusted by remote control. The pin 115 actuates a snap-action switch 122 which periodically disconnects and re-connects the controlled load 60. The invention may be applied to a prepayment meter.