Information Brochure

Interrupting Attachments

Arc Restrictor The arc restrictor is an extremely effective means of interrupting transformer magnetizing and line charging currents. The arc restrictor consists of a tapered rod arranged with a latch so that it is subjected to a large deflection while the switch is opened. At a point in the opening operation when sufficient air gap has been established at the main contacts, the horn is released from the latch and travels at a very high speed, whipping out the arc. The need for very high contact speed comes about from the race between the rise of restored voltage across the contacts and the buildup of dielectric strength after current zero. If sufficient speed is attained, arcing will persist only until the first time the current in its 0-cycle excursions passes through zero. Thereafter, the moving arc restrictor contact builds up a gap of un-ionized air establishing a dielectric strength that will exceed the rise in recovery voltage so that arcing cannot recur.

Veloci-Whip Interrupter The Veloci-Whip Interrupter is an air switch attachment used to interrupt transformer magnetizing and line charging current. The Veloci-Whip is a spring-loaded high-speed whip interrupter. The enclosed spring stores energy to allow the whip to travel at a much higher rate of speed once released form the whip latch. The protective rubber boot dampens the vibration and whipping action to avoid any re-entry into the arc zone thus avoiding the opportunity for re-strike. The beryllium copper whip eliminates any curvature set over an extensive number of operations.

Because of the rapid arc extinction, switches (except the “DRV”& “FAS-2V”) equipped with the Arc Restrictor or Veloci- Whip can be mounted on disconnect phase spacing rather than horn gap phase spacing. Arc restrictors and Veloci-Whips can be mounted on vertical break or single or double side break switches. In the case of a double side break switch, two shorter rods are used, one for each separable contact.

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