NAVFAC P 34
Closing Operation. Once the drive springs (Figure 5-15) have been charged, the breaker can be dosed by lifting
the dose lever (Figure 5-12) or by energizing the dosing solenoid (Figure 5-16). Either method disengages the trip dosing
roller and allows the drive springs to discharge. The discharging drive springs rotate the drive shaft (Figure 5-17)
clockwise. The clockwise rotation of the drive shaft gives the drive spring bearing (Figure 5-18) a downward motion.
The drive spring bearing engages the toggle cam, thus rotating the front of the toggle cam up and the rear of the toggle
cam down the catch. The front of the toggle cam is connected to the main shaft (Figure 5-16) by the drive linkage
(Figure 5-18). The upward motion of the front of the toggle cam thus rotates the main shaft counterclockwise and
compresses the return springs (Figure 5-16). The drive connecting links (Figure 5-15) transform the rotary motion of the
main shaft into a linear motion which doses the vacuum interrupter contacts. The trip opening cam (Figure 5-18) forces
the entire toggle assembly to remain latched in this position. When the drive springs discharge, rotating the drive shaft in
a counter-clockwise direction, the descending lift arm rotates the drive lever such that the drive lever completes the
remaining 360 degrees of rotation to its initial position where it can once again perform a drive spring charging operation.
The gear shaft and drive hub rotate with the drive lever. The drive hub rotates out of contact with the drive block since
the gear (Figure 5-17) rotates freely on the gear shaft, the gear remains stationary. The rotation of the drive hub is such
that the pawl lift slide follows the cammed surface of the drive hub until the pawl lift slide moves back below the gear
teeth, permitting the drive pawi to engage the gear. The charging motor limit switch cam (Figure 5-16) rotates with the
gear shaft and doses the charging motor limit switch, energizing the charging motor which once again charges the drive
Opening Operation. With the return springs (Figure 5-16) charged, the operating mechanism is now ready to
perform an opening operation. If the open lever (Figure 5-12) is lifted or if the opening solenoid (Figure 5-16) is
energized, the trip opening cam (Figure 5-18) will be rotated clockwise out from under the toggle bearing. The force of
the charged return springs pushing down on the front of the toggle cam will cause the rear of the toggle subassembly to
rotate clockwise. When the rear of the toggle cam dears the catch, the return springs will completely discharge, rotating
the main shaft (Figure 5-16) and the toggle cam clockwise. The clockwise rotation of the main shaft is transformed to a
linear motion by the drive connecting links (Figure 5-15). The drive connecting links are connected to the vacuum
interrupters (Figure 5-13), and their motion opens the vacuum interrupter contacts.
Spring Discharge Interlocks. The spring discharge interlocks (Figure 5-15) are located directly below the opening
and dosing solenoids (Figure 5-16). Three cams, located on the floor of the skeleton cell, engage the spring discharge
interlocks in such a manner that the primary disconnects (Figure 5-13) cannot be engaged or disengaged with the
interrupter contacts in the closed position and all springs are automatcally discharged whenever the load circuit breaker is
inserted into or removed from its cell.
Discharge to ground the primary disconnects and vacuum Interrupter mid-band rings before
handling to prevent Injury to personnel as a result of electrocution.
To avoid Injury to personnel, always remove the load circuit breaker CB101 from Its cubide
and discharge or block the return drive springs.
To avoid Injury to personnel, no electrical component will be worked on while energized.
Ensure equipment Is "tagged out" In accordance with Chapter 1, Section III, of the Operator
and Organizational Maintenance Manual and equipment Is NOT energized. Residual voltage Is
present at the generator leads with the regulator turned off, reaching SEVERAL HUNDRED
VOLTS on the generator set. Proper Insulation and Isolation of metering equipment must be
observed when testing this generator. USE PROPER TEST EQUIPMENT TO CHECK FOR
VOLTAGE before proceeding with work.