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.

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.

A monitoring-and-control drawer for an electrical enclosure is connected to an electricity source and to an electrical load and is linked to at least one communication interface allowing the drawer to be supplied with power or to communicate with an industrial computer. The monitoring-and-control drawer is mobile within the enclosure between three main positions: a disconnected position, a test position, and an operating position. At least one lateral structure comprises a mobile lateral contact (352) comprising electrical contacts (436) which, during the movement of the drawer between the test position and the operating position, are fixed with respect to a communication interface and connect the drawer to this interface. The electrical contacts are mobile along a longitudinal axis of the drawer with respect to the drawer when the drawer is between an engagement position and its operating position and are mobile along a transverse axis of the drawer when the drawer is between its engagement position and its test position.

A power distribution system is releasably secured to a power distribution panel, and includes a circuit breaker to detect a fault condition and to automatically move a circuit breaker switch from the ON position to the OFF position. The power distribution system further includes a backplane connector to provide connection to the power distribution panel and an interconnect mechanism to connect the circuit breaker to the backplane connector when the circuit breaker is moved from a disengaged position to an engaged position with respect to the backplane connector. The power distribution system further includes a guard coupled to the interconnect mechanism and configured to cover portions of the enclosure of the circuit breaker. The guard further prevents the circuit breaker switch from moving from the OFF position to the ON position until the interconnect mechanism connects to the circuit breaker to the backplane connector.

Motor control centers have units or buckets with an extendable/retractable power connection (stab) assembly and one or more operating lever interlocks that include a unit latch to latch to a cabinet and a power connection position interlock that blocks the handle of the units or buckets based on position of the power connection assembly, optionally also including a shutter cam that slides a shutter right and left.

Motor control centers have units or buckets with an extendable/retractable power connection (stab) assembly and one or more operating lever interlocks that include a unit latch to latch to a cabinet and a power connection position interlock that blocks the handle of the units or buckets based on position of the power connection assembly, optionally also including a shutter cam that slides a shutter right and left.

A spring loaded, bistable connect/disconnect mechanism for a motor control center (MCC) unit 20, provides a secure and quick means to connect and disconnect the stab 30 of a MCC unit to a vertical power bus 24. The low profile mechanism comprises a series of flat links 6, 7, and 11 and an over-center spring 8 in the top of the MCC unit, for efficient use of space. The mechanism provides an additional force to quickly connect and disconnect the stabs to and from the power bus. The mechanism enables safe insertion and removal of the MCC unit from an MCC section, by incorporating interlocks 5 to prevent the MCC unit from being inserted when the stabs are extended and to prevent the MCC unit from being removed when the stabs are extended. Interlocks prevent the extension or retraction of the stabs when the handle is in an ON position.

A spring loaded, bistable connect/disconnect mechanism for a motor control center (MCC) unit 20, provides a secure and quick means to connect and disconnect the stab 30 of a MCC unit to a vertical power bus 24. The low profile mechanism comprises a series of flat links 6, 7, and 11 and an over-center spring 8 in the top of the MCC unit, for efficient use of space. The mechanism provides an additional force to quickly connect and disconnect the stabs to and from the power bus. The mechanism enables safe insertion and removal of the MCC unit from an MCC section, by incorporating interlocks 5 to prevent the MCC unit from being inserted when the stabs are extended and to prevent the MCC unit from being removed when the stabs are extended. Interlocks prevent the extension or retraction of the stabs when the handle is in an ON position.

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.

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.