Patent NZ-595956-A (NZ)
Title: A circuit breaker with a differential current protection device, an auxiliary contact and a disconnection actuator powered from line voltage
Inventor: CHIARAVALLI MATTEO
IPC: H01H9/00
Filed: 2011-10-25
Abstract: Disclosed is an electric switching device (1) adapted to connect/disconnect an electrical distribution source and an electric load. The switching device (1) is operatively connected to a circuit having a line voltage and is comprised of a first pole (2), a second pole (3), a differential protection device (50) and an actuation device (55). The first pole (2) has at least a first moving contact (4) which can be coupled to/decoupled from a first stationary contact (5) to provide a connection between at least a first electrical terminal (6) and a second electrical terminal (7). The first electrical terminal (6) and second electrical terminal (7) are connected to the first moving contact (4) and the first stationary contact (5), respectively. The second pole (3) has at least a second moving contact (8) which can be coupled to/decoupled from a respective second stationary contact (9) to provide a connection between at least a third electrical terminal (10) and a fourth electrical terminal (11). The third electrical terminal (10) and fourth electrical terminal (11) are connected to the second moving contact (8) and the second stationary contact (9), respectively. The first (6), second (7), third (10) and fourth (11) electrical terminals are adapted to electrically connect the first pole (2) and the second pole (3) to the electrical source and to the electric load. The differential protection device (50) comprises a detection device (300, 400) adapted to detect a differential current, and an actuation device (55) adapted to cause the decoupling of the first (4) and second (8) moving contacts from the respective first (5) and second (9) stationary contacts. The differential protection device (50) is operatively connected to the first (2) and second poles (3) and is configured in such a manner that, following the detection of a differential current above a predetermined threshold, a supply voltage drawn from the line voltage present between the first pole (2) and the second pole (3) is applied to the actuation device (55) to cause the decoupling of the first (4) and second (8) moving contacts from the respective first (5) and second (9) stationary contacts. The differential protection device (50) is configured in such a manner as to cause interruption of application of the supply voltage to the actuation device (55) following decoupling of the first (4) and second (8) moving contacts from the respective first (5) and second (9) stationary contacts, regardless of whether the electrical source is connected to the first (6) and third (10) electrical terminals or to the second (7) and fourth (11) electrical terminals. The differential protection device (50) comprises an auxiliary contact electrically positioned in series between the actuation device (55) and the first pole (2). The auxiliary contact is operatively connected to the first moving contact (4) in such a manner as to interrupt the series connection between the actuation device (55) and the first pole (2) following decoupling of the first moving contact (4) from the respective first stationary contact (5). The auxiliary contact comprises a first conductor element (201) electrically connected to the actuation device (55) and adapted to operatively interact with the first moving contact (4) in such a manner as to be coupled to the first moving contact (4) when the first moving contact (4) is coupled to the respective first stationary contact (5), and to be decoupled from the first moving contact (4) when the first moving contact (4) is decoupled from the respective first stationary contact (5).