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Page 282

| Figure 14-14 Adjustments for induction type of relays: Current coil taps and time lever setting. |

| line with one another. The contacts must have the required wipe and gap for the particular relay. |

| Relay contacts are usually of two kinds, hard-surface or soft-surface types. Hard-surface contacts are made of various alloys. Soft-surface contacts are either made of solid silver or plated. Improper cleaning of silver-plated contacts will soon remove the plating. All silver contacts need special attention since the soft metal will wear away at an excessive rate if carelessly cleaned. |

| Relay contacts have various shapes, depending on their size and application (Fig. 14-15). Sometimes, both contacts are flat; other times, one contact is convex and its mate flat. The original shape of a contact must be retained during its cleaning and dressing. If burning or pitting has distorted the contact, it must be reshaped and restored to its original shape or replaced. |

| Hard alloy contacts may be cleaned by drawing a strip of thin, clean cloth or paper between them while they are held together (Fig. 14-16). In some cases, the cloth may be moistened with a cleaning fluid. They may be polished with a dry cloth or paper strip. If hard contacts are corroded, burned, or |

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