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Page 147

| Figure 8-17 Top view of three-pole circuit breaker in one tank. |

| single-pole construction with elliptical tanks in order to resist the greater internal pressures. Breakers of larger capacity are usually single pole as well but employ circular or round tanks. Round tanks, however, may be used even for low-voltage, heavy-current breakers in which all (two or three) poles are placed in the same tank. Whenever all poles are mounted in one tank, insulating partitions (usually made of special insulating compounds and laminated for greater strength) may be installed between them. Tanks may also be fitted with liners of the same insulating material (Fig. 8-17). |

| Moving Contacts.. |

| Since moving contacts are usually designed to move upward to close, they are often mounted on a metal crossbar and operated by an insulated lift rod (Fig. 8-18). The rod may be of an insulation-impregnated, tough wood such as hickory; it may also be laminated for greater strength: For heavy duties, multiple rods may be used. |

| Figure 8-18 Lift rod assembly. |

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