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Page 187

| Figure 10-9 Air-break switch with interrupter unit: (A) Closed switch, and (B) cutaway of interrupter unit. |

| both the blade and the inner surfaces of the stationary contacts. This type of contact is usually associated with air-break switches. |

| Area contact is usually achieved by the switch blade's slipping between stationary contacts on both sides, producing a wiping motion that maintains a clean surface on both the blade and the stationary contacts. The stationary contacts may consist of the inside surfaces of the clip or jaws and exert pressure through the elasticity of the shaped metal. The contacts may also be separate, in which case the pressure is supplied by springs (Fig. 10-11). Area contact types of stationary contacts are usually employed in disconnect switches. |

| Whatever type is used, it is necessary to hold the electrical resistance of all contacts to low levels to keep them from overheating. |

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