34kV 600A Single Pole Switch
This switch is used for both capacitor and arc furnace switching. It is solenoid operated because it is used in three phase sets requiring simultaneous contact closure. It can close at zero voltage for capacitor switching or at peak voltage for arc furnace switching. Its solenoid operating current is 60 to 65 amperes peak for 1½ cycles. An inadequate current supply is a common cause of improper operation. This switch has one form A (e.g. normal open) and one form B (e.g. normal closed) auxiliary contact. The controls for capacitor switching are shown here. Repair parts are shown beginning here.
Multiple switches are used in parallel for arc furnaces with up to 4000 amperes primary current. The switch current rating is derated to 500A when used in parallel. Arc furnace controls that can operate from one to six switches per phase are shown here. An arc furnace transformer control can optionally be operated using either resistor insertion or peak voltage closing to reduce in-rush currents.
Accessories available for this switch include both current limiting reactors and also resistor modules. The 30 micro henry reactor replaces the buss bar between the two modules. The reactor is used to limit in-rush currents when two capacitor banks are installed in parallel on a single buss. This switch also can be adapted as a resistor insertion switch by installing two 80ohm resistor modules, one each, on top of the two vacuum interrupter modules. The two resistor modules are then series connected with the buss bar and have a total series resistance of 180ohms. The controls required are shown starting here. The reactors and resistors are shown here.