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| Figure 14-18 Potential transformer connection. |

| Potential transformers are connected across the line as shown in Fig. 14-18. Current transformers are connected in series with the line, as shown in Fig. 14-19. Because the turn ratio of current transformers can produce very high voltages, extreme care should be exercised when handling them; they should be short-circuited when being disconnected. See Chap. 1. |

| Figure 14-19 Current transformer connection. |

| For causes and remedies when troubleshooting protective relays, see Table 14-1. |

TABLE 14-1 Troubleshooting Protective Relays

Condition

Possible Cause

Suggested Remedy

Relay not operating

Contacts not making

| Check and adjust plunger, armature, disc, or cylinder. Check contact arm and adjust. Dress contacts or replace if necessary. |

Poor contacts

| Realign contacts. Clean and dress them or replace if necessary. Tighten connections. |

Coil not operating

| If wrong coil, replace. If short-circuited turns, replace. |

Open circuit

| If broken wire, repair. If poor connection, tighten. |

| Relay operating too fast or too slow |

Settings incorrect

| Check and adjust to proper settings. |

| (Table continued on the next page) |

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