Abstract: A seal apparatus having a seal member and a plurality of fasteners is mounted on an arc hood of a cassette in a switchgear cabinet and resists leakage of arc gases through a gap between the arc hood and a circuit breaker mounted in the switchgear cabinet. The seal member is flexibly received against the circuit breaker in a racked position and is preferably at least nominally deflected thereby to resist the flow of arc gases in a leakage direction through the gap. The seal member thus resists the arc gases from coming into contact with a plurality of line conductors at the rear of the circuit breaker until the arc gases have at least somewhat cooled, deionized, and/or slowed. The seal apparatus thereby resists arc gases from inducing arcing between adjacent line conductors, whereby the circuit breaker can be operated at substantially higher voltages.

Abstract: An electromagnetic blow-open device for a pole of a circuit breaker where the pole has a stationary contact and a movable contact. The movable contact includes contact fingers mounted on a contact carrier. The contacts have an open position and a closed position. The pole further has an associated rotatable pole shaft. The electromagnetic blow-open device includes a collapsible linkage having a rigid position and a changeable position. The collapsible linkage is disposed between, and coupled to, the pole shaft and contact carrier. The collapsible linkage is maintains the stationary contact and the movable contact in the closed position while the collapsible linkage is in the rigid position and to allow the stationary contact and the movable contact to move to the open position when the collapsible linkage is in said changeable position. The electromagnetic blow-open device also includes an actuator arm which is coupled to the collapsible linkage and is responsive to an over-current condition in the pole.

Abstract: A clutch assembly for an electrical switching apparatus which has a close spring working in conjunction with a cam disposed on a cam shaft, wherein the close spring provides a rotational force to the cam shaft in a forward direction. The spring clutch is disposed on the cam shaft and allows the cam shaft to rotate in the forward direction but prevents rotation of the cam shaft in the opposite direction.

Abstract: An electronic trip unit for a circuit breaker having two current sensors per phase, wherein the first magnetic core current transformer is designed to monitor current in the normal and overcurrent range, and the second low-permeability core sensor is designed to produce an override trip signal at or below the short time withstand current rating of the circuit breaker. In a second embodiment the electronic trip unit includes only the low-permeability core sensor that has negligible output in the normal current range.