Method and apparatus for interrupting large current
AssigneeHughes Aircraft Company
InventorWolfgang Knauer
Life of this patent
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Abstract
Large current is interrupted against high voltage by a high speed mechanical opening line switch connected in series with a saturable reactor. A commutation capacitor is discharged through the closed switch against the line current to produce a current zero. Near the time of current zero the line switch is opened to produce arc free interruption. A dV/dt capacitor is paralleled around the switch to limit the rate of voltage rise. High contact speed of the line switch limits the size of the required dV/dt capacitor to what can be justified economically.
Claims12
Switching apparatus for interrupting large current comprising:
- a main branch comprising a saturable reactor, main switch contacts serially connected therewith, said main switch contacts having means connected thereto for rapidly opening said main switch contacts;
- a commutation branch connected in parallel to said main branch, said commutation branch comprising the serial connection of a commutation capacitor, an inductor and a commutation switch;
- and
- means connected to control both said main switch contacts and said commutation switch for discharging commutation current through said main switch contacts to reduce current therethrough to zero and for opening said main switch contacts when the current therethrough is substantially zero.
The method of interrupting large current by means of a switching apparatus which comprises a main branch consisting of a saturable reactor connected in series with fast opening main switch contacts and a commutation capacitor dischargeable through the main switch contacts to cause a commutated zero therein comprising the steps of:
- discharging the commutation capacitor through the closed main switch contacts to induce a current zero therethrough;
- and
- opening the main switch contacts substantially at the time of the current zero to interrupt current in the main branch without arcing of the main switch contacts.
Dependencies are inferred from the claim text.