Circuit Breaker Section Interlock System Operation

The racking mechanism moves the circuit breaker from the test/disconnected position to the connected position and vice versa.

Push the circuit breaker into the compartment to the test/disconnected position, and the disconnect release handle engages (see Circuit Breaker Release Handle).

With the front door closed, insert the racking handle and rotate it clockwise to rack the circuit breaker into the connected position. When in the connected position, the circuit breaker’s forward motion stops. Do not over torque the racking handle once the circuit breaker motion stops. Excessive torque damages the racking mechanism if the circuit breaker does not move. Determine the cause before continuing.

With the door closed, the position indicator (see Racking Port, Handle, and Section Position Indicator) shows if the circuit breaker is in the test/disconnected, transport, or connected position. With the door open, two arrows on the left-hand rail show if the circuit breaker is in the test/disconnected position or in the connected position.

DANGER

hazard of electric shock, explosion, or arc flash Apply appropriate personal protective equipment (PPE) and follow safe electrical work practices. See NFPA 70E, NOM-029-STPS-2011, or CSA Z462. When the switchgear is energized, always open and close the circuit breaker, and rack the circuit breaker from one position to another with the door closed. Never use force to move the circuit breaker inside the circuit breaker section. If a mechanism is not operating smoothly, look for the cause. Failure to follow these instructions will result in death or serious injury.

To remove a circuit breaker from the connected position to the test/disconnected position:

• Open the circuit breaker electrically with the compartment door closed, and with the racking handle, move the circuit breaker to the test/disconnected position. Do not over torque the racking handle once the circuit breaker motion stops. Excessive torque damages the racking mechanism if the circuit breaker does not move. Determine the cause before continuing.

In normal operation, the control power plug automatically connects and disconnects as the circuit breaker is moved into and out of the connected position.

To test the control system with the circuit breaker in the test/disconnected position:

1. Rotate and pull the handle of the secondary control power receptacle forward until it can be rotated again and locks the receptacle in position. The circuit breaker can now be electrically operated the same as in the connected position.

2. Check all electrical functions; push the receptacle back in its normal operating position.

3. Rack the circuit breaker into the connected position.

The disconnect position latch blocks the circuit breaker from rolling out of the compartment in the test/disconnected position. To remove the circuit breaker from the section, pull the release handle of the circuit breaker.

In normal operation, when the control plug is engaged, the motor automatically charges the circuit breaker closing springs. The springs can also be charged manually, using the manual spring charging mechanism. This feature is provided for testing and maintenance purposes, and for emergency operating conditions.

DANGER

hazard of electric shock, explosion, or arc flash Apply appropriate personal protective equipment (PPE) and follow safe electrical work practices. See NFPA 70E, NOM-029-STPS-2011, or CSA Z462. Never manually close a circuit breaker in the connected position unless the opening source of power and protective relays are connected and operable. Failure to follow these instructions will result in death or serious injury.

Manual CLOSE and OPEN push buttons are located at the front of the circuit breaker. These push buttons operate the circuit breaker whether the circuit breaker is charged manually or electrically. Use them only when testing the circuit breaker during start-up or maintenance. Refer to the Type VR Circuit Breaker instruction bulletins 6055-31 (1200 and 2000 A, 50 kA) and 6055-33 (3000 A, 50 kA and 1200, 2000, 3000 A, 63 kA).

DANGER

hazard of electric shock, explosion, or arc flash Apply appropriate personal protective equipment (PPE) and follow safe electrical work practices. See NFPA 70E, NOM-029-STPS-2011, or CSA Z462. When the switchgear is energized, never use the manual OPEN and CLOSE push buttons on the front of the circuit breaker. Use the control switch with the front door closed. Failure to follow these instructions will result in death or serious injury.

This section contains information related with the air cooling for 4000 A switchgear. It includes the logic overview and the fan location, as well as explaining how to locate the indicator devices in the doors of this specific equipment.

• MT/ME = Main fans turn on when the continuous current is equal or above 2,500 A. If the current is below 2,500 A the fans remain off.

• CMA = This meter is on at all times measuring the continuous current.

• The high current relay in this meter closes after ten seconds when the current relay is equal or above 2,500 A.

• CMB, CMC, CMD = These meters and the main fans turn on once the high current relay in CMA is closed. The meters indicate current draw of the circuit breaker compartment, bus compartment, and cable compartment fans respectively.

• BE/BT = These are the backup fans and turn on after ten seconds if any of the main fans no longer move air. A low current relay in meters CMB, CMC, CMD monitors the current on each set of fans (circuit breaker, main bus, or cable compartment).

• WF = White indicating light that is ON when backup fans are running,- indicating problems with the main fans in that particular compartment. Inspect the fans and control circuit when an alarm is on.

• TB1, TB2, TB3 = Test backup fans pushbuttons. Do not hold for more than ten seconds. These test the backup fans in the circuit breaker, bus, and cable compartment respectively.

• RH = Red light that is ON when air temperatures in circuit breaker section exceeds 140°F (60°C).

• An additional discrete LED alarm indicator is on the front panel of the CMA, CMB, CMC, CMD meters.

• It is optional to have CMB, CMC, CMD energized at all times or use the contact relay per diagram.

Note the following:

• The logic of the operation cannot be changed.

• The location of the fans cannot be changed.

• The supplier and type of fans cannot be changed unless reviewed and approved by Schneider Electric and UL.

• Metering devices and relays can be changed per customer preferences.

• The type of alarms and signal can be changed per customer preferences.

• CMA, CMB, CMC, CMD: These meters are true RMS meter 262-30A-AC01.

• PD1/PD2: Dual relay output 262-RLY.

• MT/ME Main fans (four in circuit breaker compartment and three in bus and cable compartments).

• BT/BE Backup fans (two in circuit breaker compartment and one in bus and cable compartments).

• Fans control equipment typically installed on upper door.

• The fan system is powered by a costumer supplied UPS at 120 VAC.

Upper Door Detail Devices Can Be Installed in Either Upper or Lower Control Box Door

Devices associated with the fan cooling system are typically installed in the main section(s) upper door, on the upper portion of the door. The lower portion of the upper door can be used for additional devices required by customer.

Special consideration must be given to the switchgear sections that employ fan cooling. In addition to all items in Inspection and Maintenance, the following additional steps are required:

• Fans potentially increase the volume of contaminants that accumulate throughout the equipment. Increase maintenance frequency if the equipment is subject to a high level of environmental contaminants, and/or the fan system is frequently in operation.

• Perform visual examination of the fan cooling hardware, including blades and cages annually. Abnormal operation requires immediate corrective action to help ensure the system functions as intended. During the inspection, look for damage, contaminants or pollutants throughout the switchgear section. Remove any buildup of dust or foreign materials by vacuuming and wiping with a clean dry cloth.

• Test the fan control system annually, (at a minimum) using the “TB” – Test backup fans pushbutton (for Circuit Breaker – TB1, for bus TB2, and for cable TB3). Momentarily press and the TB test button (no longer that ten seconds) to verify the backup fans are functioning properly. If the button is help longer that ten seconds, the backup fans will operate until control power for the fans is removed and reapplied. Removing the control power from the fans and then reapplying the control power resets the logic to normal operation. Extended operation of the fans will reduce their useful life. If a backup fan does not operate during the pushbutton test, contact Schneider Electric Services for assistance. Cooling fans are not a user replaceable item. Loading on the lineup should be restricted to 3000 A or less until the backup fans can be restored to proper working order.

The warning lights provide important information on the status of the system and should not be ignored.