5-20. LOAD CIRCUIT BREAKER CB1D1 SERVICE.
Ensure that the generator set is shutdown and the unit fully
deenergized, load cables are in the park position and surge protectors are grounded. Remove load circuit breaker
CB101 in accordance with paragraph 2-17. Use a dean dry both to remove dirt and moisture that may have collected on
the vacuum interrupters and all insulating parts. Ensure that all electrical connections are tight and dean. Lubricate the
load circuit breaker in accordance with Table 5-1. It should be noted that all bearings used in load circuit breaker are
sealed and do not require lubrication. Table 5-1 provides the location of all lubrication points, the type of lubrication
required, and the two methods of lubrication. Method I is the periodic lubrication required after 2000 operations (Figure
5-12) or 1 year. Method 11 is the lubrication procedure to be used whenever the load circuit breaker is disassembled for
repair. Severe operating conditions, such as use in extremely hot, cold, or dusty environments, may warrant more
frequent lubrication intervals. Load circuit breaker CB101 must be manually operated several times after lubrication and
observed for proper operation. Manually operate the load circuit breaker as follows: a. Move the manual charge arm
assembly (Figure 5-12) up and down using the handle end of the racking crank until the drive springs are fully charged.
The drive springs are fully charged when the CHARGE-DISCHARGE indicator reads CHARGED, and the manual
charge arm assembly can no longer be raised.
To avoid Injury to personnel, always remove the load circuit breaker from Its cubide and
discharge or block the return and drive springs.
Discharge to ground the primary disconnects and vacuum Interrupter mid-band rings before
handing to prevent Injury to personnel as a result of electrocution.
5-21. LOAD CIRCUIT BREAKER CB101 ADJUSTMENT.
During periodic inspections and when the load circuit
breaker is replaced or repaired, the following adjustments must be checked. To perform these adjustments, first remove
the breaker from its cubide in accordance with paragraph 2-17, then remove the front cover (1, Figure 5-19) by removing
bolts (2), and lockwashers (3) and washers (4).
Whenever an adjustment is to be checked or performed with the drive springs In the charged
position, It Is mandatory to block the drive springs by placing the blocking pins In the holes at
the upper end of the drive spring center shafts (the blocking pins are located In the tool box).
Trip Open Eccentric Adjustment. With the breaker in the OPEN position and the drive springs charged, the vertical
free movement in the opening solenoid plunger (C, Figure 5-18) should be 1/8 ±1/16 inch (3.2 ±1.6 mm). Loosen the
locking bolt and rotate the eccentric to move the trip open arm until the correct distance is obtained.
Toggle Bearing Clearance Adjustment With the breaker in the OPEN position and the drive springs charged, the
clearance between the toggle bearing (Figure 5-18) and the trip opening cam should be 1/32 +1/32-0 inch (0.8 +0.8/-0
mm). If adjustment is necessary, the toggle subassembly retainer nut should be adjusted clockwise to increase
clearance; counter-clockwise to decrease clearance.
Charging Motor Limit Switch Adjustment. The charging motor limit switch is actuated by the charging motor limit
switch cam (Figure 5-16). The charging motor limit switch serves to energize the charging motor (Figure 5-15) during a
drive spring charging operation and deenergize the charging motor when the drive springs reach the fully charged
position. The charging motor limit switch is properly adjusted it its contacts are open when the drive springs are in the
fully charged position and closed when the drive springs are discharged. The position of the charging motor limit switch
contacts can be determined by using an ohmmeter to test for continuity. If adjustment is necessary, loosen the two
screws (136, Figure 5-19) which hold the charging motor limit switch in place and move the switch up or down as
required. Tighten the two screws (136) after completing the adjustment.