Overview of the Electrical Auxiliaries

The auxiliary switch is a multi stage switch used to operate circuits that depend on the position of the circuit breaker contacts. It is housed in the wiring module behind the front cover of the circuit breaker and a cover plate. It is located to the upper left of the circuit breaker ARF200 operating mechanism (see Circuit Breaker Mechanism Area). The schematic diagram illustrates how each of the auxiliary switch contacts interconnect with the circuit breaker circuitry (refer to Typical Circuit Breaker Electrical Schematic).

DANGER

loss of circuit breaker control Ensure the power connection on release coils is continuously energized. Ensure the power connection on release coils is not connected to the circuit breaker trip/close contact. Ensure the order connection on release coils is connected to the circuit breaker trip/close contact. Ensure the common connection on release coils connects to the negative/grounded side of the release coil power supply. Failure to follow these instructions will result in death or serious injury.

The opening and closing coils used on the EvoPacT circuit breaker are electronic coils and must be continuously supplied with power for proper operation (refer to Typical Circuit Breaker Electrical Schematic). When energized by the switchgear or remote circuitry, these coils release the open or close latches located inside the mechanism. The standard location of the open and close release coils is mounted on the top center of the ARF200 operating mechanism (see Circuit Breaker Mechanism Area). They feature an integrated electronic circuit board that allows for:

• self-checking functionality reporting of internal coil failures, such as failure of the electronic board or coil winding continuity.

• indication of coil activation to report coil activation timing.

• the use of external trip coil supervision devices.

The standard coil activation connections are wired to the open/close circuits of the switchgear. The additional coil features require the circuit breaker to be configured with particular specifications to permit functionality.

The MX1 opening release coil opens the circuit breaker. The XF closing release coil closes the circuit breaker. An optional MX2 or MN opening release coil to open the circuit breaker can also be specified (refer to Circuit Breaker Equipped With an MN Under-Voltage Opening Release, for further information on the MN release coil). The MX2 opening release coil provides an option for having an additional tripping coil on the circuit breaker ARF200 operating mechanism.

The coils feature five external connections. Three connections are allocated to coil activation and two are for additional features. The three activation connections consist of one “power”, one “order”, and one “common” connection:

• The power connection is required to be continuously energized and is the power supply of the electronic circuit board of the coil. Ensure that the power connection is not connected to the circuit breaker trip/close contact.

• The order connection activates the plunger of the coil when energized. Ensure that the order connection is connected to the circuit breaker trip/close contact(s) and, if required, to the trip coil supervision device.

• The common connection connects to the negative/grounded side of the release coil power supply.

Manual and electrical circuit breaker closing operations may be prevented if the optional circuit breaker closing blocking electromagnet is provided.

The electromagnet assembly is composed of an electromechanical coil and mechanical linkages, and an indication contact that is closed when the coil is energized and open when the coil is not energized (refer to the Typical Circuit Breaker Electrical Schematic for further details). The assembly for the electromagnetic interlocking of the racking mechanism is located on the upper right side of the ARF200 operating mechanism (see Circuit Breaker Mechanism Area).

• When the electromagnet coil is energized, closing of the circuit breaker is permitted.

• When the electromagnet coil is not energized, then both mechanical and electrical closing of the circuit breaker is blocked.

DANGER
ANTI-PUMP loss The XF closing release must not be wired in series with any of the circuit breaker auxiliary contacts. Failure to follow these instructions will result in death or serious injury.

The EvoPacT circuit breaker is provided with a mechanical anti-pump function system embedded in its mechanism. The anti-pump system ensures that the closing order that previously caused the circuit breaker to close must be reset in order to allow the circuit breaker to close again. This prevents the breaker from “pumping” in case of a latched close command is mechanically or electrically applied to the circuit breaker.

It is mandatory that auxiliary contacts of the circuit breaker are not wired in series to the closing release (XF) and its close contact in order to prevent defeating the mechanical anti-pump system of the EvoPacT circuit breaker.

The information in this section describes the EvoPacT electrical circuit components. The following electrical diagrams show a standard application for the EvoPacT circuit breaker (see Typical Circuit Breaker Electrical Schematic) and racking mechanism (see Motorized Racking Mechanism Option — Electrical Schematic). The electrical circuit designs may vary, depending upon customer requirements, EvoPacT specifications, and switchgear integration.