Abstract: An electrically isolated rotor assembly for a cassette assembly of a circuit breaker includes a rotor having a first side and an opposing second side, a first isolation cap disposed on the first side, a second isolation cap disposed on the second side. Each isolation cap preferably includes a centrally located knob with a bushing surrounding each knob, wherein the bushings are sized for securement within apertures within first and second cassette half pieces.

Abstract: Apparatus for adjusting the calibration of a thermal trip unit which is to be used in conjunction with an electrical circuit breaker. A rotatable knob is provided which adjusts the trip unit to between one hundred percent of the rating of the circuit breaker and some value which is less than one hundred percent. An adjustable stop screw is provided to engage the rotatable knob when the knob is rotated to adjust the calibration of the trip unit to the desired value which is less than one hundred percent of the rating of the breaker. The adjustable stop screw thereby limits travel of the adjustable knob between only one hundred percent of the rating of the circuit breaker and the desired value which is less than one hundred percent.

Abstract: In a plural phase overload relay, a pivot lever (12) is mounted to the ambient compensator deflector (9), and a second pivot lever (34) is mounted to both driver and follower slide bars (36 and 38) and driven thereby to engage and pivot the first lever on the ambient compensator deflector to trip a cut-out switch. The ambient compensator deflector adjusts both the three phase current trip threshold and the loss of phase current trip threshold, and also affords ambient compensator of each. A constant ratio relationship between these two thresholds is provided throughout the entire range of current trip threshold settings. The driver bar moves a first distance for three phase trip and a second shorter distance for loss of phase trip. The ratio of these distances is constant notwithstanding adjustment by the ambient compensator deflector changing the length of such distances.

Abstract: A multi-pole circuit interrupter having a first pole unit provided with an operating mechanism and a second pole unit provided with no operating mechanism. Each of the pole units comprises a movable contact, a stationary contact, and a contact arm assembly for supporting the movable contact of the respective pole unit including a first contact arm and a second contact arm pivotally supported by a common pin. The first contact arm in the first pole unit have an elongated guide hole extending in a direction of movement of the movable contact and is directly connected to the operating mechanism. The second contact arm has an elongated hole extending substantially in a longitudinal direction thereof. A spring-biased sliding pin extends through the elongated hole and the guide hole.

Abstract: Each bimetallic element is associated with one phase and is attached with one end thereof to a metallic support mounted at a wall of a housing. Each support comprises two supporting surfaces or faces lying in a plane which extends at right angles to the bending or deflection direction of the free ends of the bimetallic elements. When all the bimetallic elements have the same temperature, the distance of this plane from the bendable ends of the bimetallic elements is the same for all bimetallic elements. The supports are supported at counter surfaces or faces provided at the housing wall via a plate-shaped intermediate layer of the same thickness. The counter surfaces for all supports lie in a common plane extending at a distance, which corresponds to the thickness of the intermediate layer, from the plane defined by the supporting surfaces and in substantial parallelism thereto.

Abstract: A double-pole rocker switch with thermal overload protection is constructed as a fully functional sub-assembly which may be tested and adjusted prior to insertion in a tubular housing. The sub-assembly is held in the housing by releasable locks for subsequent servicing. All component elements of the switch are carried on the sub-assembly, including all electrical contacts. In particular, the sub-assembly has a base in which two pairs of electrical contacts are fixedly disposed, each pair being contacted by a spring-loaded contact bridge in one position of the rocker. This position can be attained, however, only if a movable contact block is held at one end by a fulcrum provided by a latch. The latch pivots in a V-shaped groove and may be removed from engagement with the contact block by a bimetallic strip under conditions of overload. In that condition, even deliberate actuation of the rocker cannot result in a closure of the switch because of the absence of the fulcrum.

Abstract: The disclosure relates to a three phase aircraft circuit breaker in which a single push-pull manual operator controls a single mechanical latch for the three poles. Slidable contact carriers in each of the phases are controlled by thermally actuated latches in each of the poles which are released upon the occurrence of an electrical overload by a current responsive bimetal in each pole. An ambient temperature responsive bimetal is provided in each phase. A common trip mechanism effects opening of all poles of the circuit breaker upon the occurrence of an overload in any phase.

Abstract: An overload switching relay for a multi-phase electricity supply responds to the value of the currents in the individual phases and actuates a contact-breaking switch in the event of either (i) the mean value of the currents on all phases exceeding a first threshold, and (ii) any differential arising, above a second threshold, between the currents of any two phases: means are provided to increase the threshold to differential actuation as the mean value of the entire plurality of currents increases.

Abstract: A multipole excess current switch composed of a plurality of single pole excess current switches each arranged to be placed in series in a respective circuit to be protected, each single pole switch including a U-shaped bimetallic member connected to conduct the current through such circuit and to undergo a change in shape when conducting an excess current, and a spring loaded switching arrangement arranged to open the switch in response to movement of the bimetallic member, and the switching arrangements of all of the single pole switches being mechanically connected to trigger operation of the spring loaded switching arrangements of the other single pole switches when one of the switches opens in response to an excess current through its associated circuit.

Abstract: A multiple circuit thermal circuit breaker comprises a plurality of single circuit breakers which are contained in a housing. A single manually operable control is provided to effect resetting of all the circuit breakers and each circuit breaker includes a temperature sensing means through which the current flowing in the respective breaker flows, the temperature sensing means when the current exceeds a predetermined value acting to trip the respective circuit breaker. Linkage is provided between the circuit breakers so that when one is tripped by operation of its temperature sensing means the other circuit breakers will also be tripped.