Abstract: A troubleshooting compartment for a motor control center unit, provides electrical access to test control points inside the motor control center unit, without exposing the operator to electrical hazards from the main line-voltage components inside the motor control center unit. The troubleshooting compartment comprises an accessible compartment contained within a motor control center unit, which is separate from a main line-voltage compartment of the motor control center unit, the accessible compartment having an access side to enable operator access to the accessible compartment without need to open the main line-voltage compartment; an accessible compartment door covering the access side of the accessible compartment from a front side of the motor control center unit; and feed-through terminals mounted within the accessible compartment, for test points and pilot devices operating at low, control voltages.

Abstract: A connect/disconnect mechanism for an MCC unit, prevents a circuit breaker from being turned on while the unit is being inserted into an MCC section, until stabs of the unit have been connected to a power bus. A cam is rotatably mounted on a pivoted platform in the MCC unit, an actuating arm is coupled between a unit on/off handle of the MCC unit and the cam, and a bail is pivotally mounted on the pivoting platform and connected to a switch handle of the breaker. A cam surface in a slot of the cam is configured to engage a pin projecting from the bail, when the pivoted platform is forced in a backward direction to connect the stabs to the bus, thereby operatively connecting the unit on/off handle to the switch handle of the breaker.

Abstract: A troubleshooting compartment for a motor control center unit, provides electrical access to test control points inside the motor control center unit, without exposing the operator to electrical hazards from the main line-voltage components inside the motor control center unit. The troubleshooting compartment comprises an accessible compartment contained within a motor control center unit, which is separate from a main line-voltage compartment of the motor control center unit, the accessible compartment having an access side to enable operator access to the accessible compartment without need to open the main line-voltage compartment; an accessible compartment door covering the access side of the accessible compartment from a front side of the motor control center unit; and feed-through terminals mounted within the accessible compartment, for test points and pilot devices operating at low, control voltages.

Abstract: A connect/disconnect mechanism for an MCC unit, prevents a circuit breaker from being turned on while the unit is inserted inserted into an MCC section, until stabs of the unit have been connected to a power bus. A cam is rotatably mounted on a pivoted platform in the MCC unit, an actuating arm is coupled between a unit on/off handle of the MCC unit and the cam, and a bail is pivotally mounted on the pivoting platform and connected to a switch handle of the breaker. A cam surface in a slot of the cam is configured to engage a pin projecting from the bail, when the pivoted platform is forced in a backward direction to connect the stabs to the bus, thereby operatively connecting the unit on/off handle to the switch handle of the breaker.

Abstract: An improved latch mechanism is provided for use in a motor control center having a door and a frame which the door cooperatively closes onto. The latch mechanism is capable of securing the door against the frame and is rotatable between an OPEN position and a CLOSED position. The latch mechanism includes a body portion, rotatably coupled to the door, capable of engaging a slot disposed in the frame for securing the door against the frame. A stop, disposed on the body portion, is provided for limiting the rotation of the body portion.

Abstract: A motor control unit for use in an electrical enclosure is provided, the motor control unit includes a connector stab assembly of a molded plastic housing having a base portion, at least one jaw connector cover extending from one side of the base portion and a corresponding bar cover extending from the other side of the base portion opposite the jaw connector. The jaw connector cover includes a pair of opposing u-shaped sidewall members. A metal bar is provided having a first end extending through the base into the jaw connector cover and a second end extending through the bar cover. The second end of the metal bar is adapted for connection to a wire conductor. A pair of jaw fingers extend from the first end of the metal bar and are partially enclosed in the jaw connector cover and are adapted to secure to a vertical bus bar. A pair of spring members are secured to the first end of the metal bar and engage each one of the jaw fingers for biasing the jaw fingers toward each other.

Abstract: The present invention provides a shutter assembly for covering an exposed electrical terminal located in a control center into which removably inserts an electrical control device connecting to the terminal. The assembly includes a shutter to cover the exposed terminal when superposed thereover. The shutter has a pivotal axis at one end, so that the opposite end of the shutter pivots away from the exposed terminal and swings clear of the control device to provide access to the terminal. The rotation of the shutter is automatically controlled to expose the terminal when the control device is inserted in the cell and reversibly pivots the shutter to cover the terminal upon removing the control device from the cell. The present invention also provides a method of safely protecting an exposed terminal mounted in a control center. A control center is provided with a partially enclosed framework for removably inserting a control device.