US 4,245,184 A · AC Solid-state circuit breaker

Abstract

A solid-state circuit breaker is provided with circuitry for permitting off/on/reset operations actuated by a mechanical toggle control switch for close simulation of magnetic circuit breaker operation. A power continuity feature is provided for load power by locating the control switch so that it opens all of the circuit, except the static power switch branch, between the source and the load, to provide a high degree of fail-safe protection for the apparatus. The power continuity feature includes means for zero crossover synchronization both upon power-up and power-down conditions. A circuit lockout feature is used so that on power-up or turn-on, operation is delayed until the occurrence of an internal power-ready condition. On power-down or turn-off, there is means for circuit retention subsequent to switch opening and internal power removal in order to accomplish load turn-off at a desired zero crossover point of the load power through the power switch. A power supply is incorporated that does not require stepdown or isolation transformers and improves capability for miniaturization of the overall circuitry and enables design of the circuit for operation at any of a wide range of frequencies.

Claims6

Dependent claims

A solid-state circuit breaker for alternating current applications comprising:

a static power switch for connection between an AC voltage supply and a load;
power supply means for developing DC voltage from the applied AC voltage supply;
a manually operable control switch connected between the supply line and said power supply means;
zero crossover circuit means with connections both with said supply line directly and with said supply line only through said control switch and said power supply means for producing a first signal indicative of the zero crossover of the AC voltage supply;
turn-on time delay circuit means for producing a signal indicative of the power supply means having achieved full operating capability after the closing of said control switch;
switch detector circuit means for producing a signal in response both to the closing of said control switch and the occurrence of said time delay signal;
control logic means for responding to the occurrence of said signals in a manner to produce an ON signal only when said zero crossover signal occurs and said switch detector signal occurs;
drive circuit means responsive to said ON signal of said control logic means for application of signals to said power switch to initiate conduction thereof.

5 more elements

Dependencies are inferred from the claim text.

AC Solid-state circuit breaker

Life of this patent

AC Solid-state circuit breaker

Life of this patent

Abstract

Claims6