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Page 172

| Figure 9-12 Lift-rod travel indicator. |

| separate module (sometimes called a bottle) containing the vacuum or gas, and maintenance is accomplished by the removal of the module and its replacement with a new one. Repair or replacement of internal parts and restoration of the vacuum or gas is performed in the shop under more controlled conditions, using the more specialized equipment available. The gas system of the sulphur hexafluoride breaker is inspected and maintained in a manner similar to that used for the compressed air system in a pneumatic operated breaker. A schematic diagram of this gas system is shown in Fig. 9-13. |

| Troubleshooting |

| The principal troubles experienced in circuit breakers are overheating; failure of the breaker to trip, to close, or to latch close; and oil problems. The causes and remedies are indicated in Table 9-1. |

| Review |

| 1. Circuit breakers may be operated directly by hand (Fig. 9-2), by remote mechanism (Fig. 9-3) and electrically by motors (Fig. 9-5) or solenoids (Fig 9-4). To insure continuity and stability of electric supply, storage batteries may be employed that may be continuously charged by floating on a distribution supply line. |

| 2. Some breakers may be automatically reclosed a predetermined number of times for predetermined periods of time (usually several cycles or seconds) before becoming locked out in an open position. This is done |

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