Switching system for cyclic supply of electrical power to a plurality of loads
First Claim
1. A switching system for maintaining substantially constant the load on a three-phase supply voltage when switching among a plurality of loads, each of said loads comprising a plurality of elements arranged in at least one three wire group, said system comprising a plurality of switch means for connecting respective at least ones of said loads to said supply, means for providing a plurality of signal codes in a predetermined sequence, a decoding circuit, responsive to said signal codes, for supplying control signals to at least ones of said switch means indicated by said signal codes, and for causing said switching in a sequence indicated by said codes, inhibiting means for preventing operation of said switch means except when the voltages on the respective supply phases have substantially zero magnitudes, means for generating first indicating signals when the magnitude of the voltage on one of said phases is adjacent zero, and means for generating second indicating signals on a subsequent occasion when the magnitude of the voltage on said one phase is adjacent zero, said inhibiting means including means, responsive to said first indicating signals, for preventing supply of said control signals except those for switch means between a predetermined two of said phases and means, responsive to said second indicating signals, for preventing supply of said control signals to said switch means between said predetermined two phases and for permitting supply of said control signals to the remainder of said switch means.
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Accused Products
Abstract
A switching system for sequential connection of a plurality of loads to an alternating current supply comprises a computer for generating switch selection data in the form of serial bits along a single line to a distributor arrangement which decodes the selection data and provides control signals to switch devices which connect the loads to the supply. The distributor arrangement includes a circuit for inhibiting supply of the control signals to the respective switch devices unless the voltage of the supply phase connected by the device is substantially zero. Additionally the control signals are time-advanced with respect to the zero voltage conditions so that the switch devices can be placed in states in which they can connect a load before disconnection of a preceding load.
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Citations
8 Claims
- 1. A switching system for maintaining substantially constant the load on a three-phase supply voltage when switching among a plurality of loads, each of said loads comprising a plurality of elements arranged in at least one three wire group, said system comprising a plurality of switch means for connecting respective at least ones of said loads to said supply, means for providing a plurality of signal codes in a predetermined sequence, a decoding circuit, responsive to said signal codes, for supplying control signals to at least ones of said switch means indicated by said signal codes, and for causing said switching in a sequence indicated by said codes, inhibiting means for preventing operation of said switch means except when the voltages on the respective supply phases have substantially zero magnitudes, means for generating first indicating signals when the magnitude of the voltage on one of said phases is adjacent zero, and means for generating second indicating signals on a subsequent occasion when the magnitude of the voltage on said one phase is adjacent zero, said inhibiting means including means, responsive to said first indicating signals, for preventing supply of said control signals except those for switch means between a predetermined two of said phases and means, responsive to said second indicating signals, for preventing supply of said control signals to said switch means between said predetermined two phases and for permitting supply of said control signals to the remainder of said switch means.
Specification