Claims
- 1. A method for interrupting power to an inductive load supplied from a three-phase high voltage source to prevent virtual chopping and using a vacuum switch having quick dielectric recovery characteristics in each phase of the high voltage network, comprising the steps of:
- opening the vacuum switch in a first phase at a given time; and
- opening at least one of the two remaining vacuum switches at a time subsequent to said given time equal to or greater than at least one-third of the period of the three-phase high voltage network frequency plus the minimum arcing time of the vacuum switch in the said first phase wherein the time of opening said at least one of the two remaining vacuum switches subsequent to said given time is less than one cycle of the power frequency.
- 2. A method as in claim 1 wherein said two remaining vacuum switches are opened simultaneously with one another.
Parent Case Info
This is a continuation of application Ser. No. 239,050, filed Feb. 27, 1981, now abandoned.
US Referenced Citations (4)
Foreign Referenced Citations (2)
Number |
Date |
Country |
963007 |
Jul 1964 |
GBX |
1473837 |
May 1977 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
239050 |
Feb 1981 |
|