A medium voltage circuit breaker for the use in high pressure environments has a vacuum interrupter with a fixed contact side and a movable contract side with a movable rod, and a drive in pressure tight insulating housing, electrical terminals to the vacuum interrupter integrated into the pressure housing, and a further pressure tight housing attached pressure tightly at the insulating housing at the movable contact side of the vacuum interrupter with the movable rod, and that the inner volume of the insulating pressure tight housing gastightly separated from the inner volume of the further pressure tight housing by a bellows, through which the movable rod is guided through and mechanically coupled to a drive, which is arranged inside the further housing.

In an embodiment, the present invention provides a medium voltage circuit breaker in high pressure subsea environment, including: a vacuum circuit breaker; and a drive in a pressure tight housing. For an electrical three-phase arrangement, one vacuum circuit breaker per phase is in arranged in a separate pole housing each, and the resulting three pole housings are mounted to a common base compartment, in which all the three drives for the three vacuum circuit breaker are arranged. The three pole housings and the common base compartment are attached such that they form commonly a pressure tight compartment.

An underarm gang operated vacuum break switch (underarm switch) has an electrically live portion under a mounting arm, which provides advantages over the standard vacuum break switch, which have the electrically live portion above the mounting arm. Because the non-electrified mounting arm is above the electrified portion, the underarm switch is safer for perching birds and other wildlife. The nature of the underarm switch also provides other benefits including a disconnect blade that when opened creates a visual gap to ensure electrical discontinuity along with a safety locking arm tied to deactivating the underarm switch. Adding to the safety measures is a visual indicator that shows an electrician when the switch is live and safe to open the disconnect blade. Other safety measures include a shock absorber assembly and inertia slowing mass protecting electrical contacts within the vacuum break switch from failing.

A vacuum circuit breaker includes: a vacuum valve accommodated in a tank having a cylindrical shape; a movable-side shield installed on a movable side of the vacuum valve; a movable-side main contact point having a tubular shape to cover the vacuum valve and the movable-side shield from radially outside; a contact point driver that moves the movable-side vacuum contact point and the movable-side main contact point in conjunction with each other; and an insulating rod that transmits a force to the contact point driver. The contact point driver includes: a low gas pressure section lever connected to a contact via a contact pressure applier that applies a contact pressure to the contact; a rotary seal shaft fixed to the low gas pressure section lever; and a high gas pressure section lever fixed to a portion of the rotary seal shaft exposed to the high gas pressure section.

An object is to eliminate, through an inexpensive structure, degradation in withstand voltage performance and degradation in energization performance caused by heating in a vacuum circuit breaker. The vacuum circuit breaker includes a main circuit structure body having an insulation rod, a vacuum valve, a movable side terminal, and the like and an insulating holder for supporting the main circuit structure body. The insulating holder is a frame structure body having opening portions in the top and bottom surfaces and both side surfaces of the section in which the vacuum valve is disposed and the section in which the insulation rod is disposed.

A vacuum circuit breaker includes a tank containing an electrical device. An opening corresponds to a terminal of the electrical device. A porcelain tube protruding from the tank is fixed to an opening base, and has a terminal conductor. A first connection conductor in the porcelain tube is connected to the terminal conductor. A second connection conductor is arranged in the porcelain tube. A third connection conductor is arranged between the first and the second connection conductor, has a closed end concave section fitted onto the first connection conductor and is connected to the second connection conductor by a fastener. A contact is disposed between said first connection conductor and the third connection conductor. The third and second connection conductors are made of a solid conductor. A center of the third connection conductor and a center of the second connection conductor are formed with a threaded section.

A medium voltage circuit breaker for the use in high pressure environments has a vacuum interrupter with a fixed contact side and a movable contract side with a movable rod, and a drive in pressure tight insulating housing, electrical terminals to the vacuum interrupter integrated into the pressure housing, and a further pressure tight housing attached pressure tightly at the insulating housing at the movable contact side of the vacuum interrupter with the movable rod, and that the inner volume of the insulating pressure tight housing gastightly separated from the inner volume of the further pressure tight housing by a bellow, through which the movable rod is guided through and mechanically coupled to a drive, which is arranged inside the further housing.

A contact assembly for an electrical component includes: a bus member; and a switching assembly structured to move between first and second positions. The switching assembly includes: a stationary contact extending from the bus member, a movable contact engaging the stationary contact when the switching assembly is in the first position and disengaging the stationary contact when the switching assembly moves toward the second position, and a switching device coupled to the bus member. When the switching assembly is in the first position, the switching device and the stationary contact are electrically connected in parallel with the bus member and the movable contact. When the switching assembly moves from the first position toward the second position, the switching device disconnects power after the movable contact disengages the stationary contact in order that electrical disconnection between the bus member and the movable contact occurs within the switching device.

An underarm gang operated vacuum break switch (underarm switch) has an electrically live portion under a mounting arm, which provides advantages over the standard vacuum break switch, which have the electrically live portion above the mounting arm. Because the non-electrified mounting arm is above the electrified portion, the underarm switch is safer for perching birds and other wildlife. The nature of the underarm switch also provides other benefits including a disconnect blade that when opened creates a visual gap to ensure electrical discontinuity along with a safety locking arm tied to deactivating the underarm switch. Adding to the safety measures is a visual indicator that shows an electrician when the switch is live and safe to open the disconnect blade. Other safety measures include a shock absorber assembly and inertia slowing mass protecting electrical contacts within the vacuum break switch from failing.

A piston rod (15) and a first piston (13) are arranged in the interior of an external cylinder (11) and internal cylinder (12); a second piston for absorbing the change of volume of operating fluid (24) is also arranged therein. Also, a first return spring (18) for returning the piston rod (15) to the interruption position is provided and a second return spring (20) for returning the operating fluid 24 into the high-pressure chamber (25) by pressurizing the second piston (14) is provided. In addition, the air in the interior of the buffering device (10) is withdrawn by a vacuum pump (38), and operating fluid (24) is thus introduced in a degassed condition.