High speed transfer switch
AssigneeTechmatics, Inc.
InventorsGeorge K. Woodworth, Forrest K. Smith
Life of this patent
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Abstract
A high speed transfer switch is provided for transferring a multiphase load among a number of multiphase A.C. power sources. If the initially selected source deviates from desired limits, the transfer switch transfers the load to an alternate source on a phase-by-phase basis. Antiparallel-connected SCRs are used to allow the load current in each phase to commutate to zero before the load is transferred to the alternate power source.
Claims49
A high speed transfer switch for transferring a multiphase load between first and second multiphase A.C. power sources, comprising:
- switching means for selectively connecting each phase of said load to the corresponding phase of said first or second power source;
- load current monitoring means for detecting a zero current condition in each phase of said load;
- and
- control means coupled to said switching means and to said load monitoring means, said control means being responsive to a detected transfer condition to cause said switching means to independently transfer each phase of the load from the first power source to the second power source immediately upon detection of a zero current condition in said phase by said load current monitoring means.
A method for transferring a multiphase load between first and second multiphase A.C. power sources, comprising the steps of:
- detecting a condition requiring transfer of said load from said first power source to said second power source;
- monitoring the current in each phase of said load in order to detect the occurrence of a zero current condition in each of said load phases;
- and
- independently transferring each phase of said load from said first power source to said second power source immediately upon detection of a zero current condition in said phase.
A high speed transfer switch for transferring a multiphase load between first and second multiphase A.C. power sources, comprising:
- switching means for selectively connecting said load to said first or second power source;
- a fault current detector for detecting a fault current in said switching means;
- and
- control means coupled to said switching means and to said fault current detector, said control means being responsive to the detection of a fault current by said fault current detector to disable said switching means in order to disconnect said load from said first and second power sources.
A method for operating a high speed transfer switch for transferring a multiphase load between first and second multiphase A.C. power sources, comprising the steps of:
- monitoring the operation of switching means interconnecting said load with said first and second power sources in order to detect a fault current in said switching means;
- and
- upon detection of a fault current in said switching means, disabling said switching means in order to disconnect said load from said first and second power sources.
A high speed transfer switch for transferring a multiphase load among first, second and third multiphase A.C. power sources, comprising:
- switching means for connecting said load to any one of said first, second and third power sources;
- control means coupled to said switching means, said control means being responsive to a detected transfer condition to cause said switching means to transfer said load from one of said power sources to another of said power sources based on a predetermined order of priority among said first, second and third power sources.
A method for transferring a multiphase load among first, second and third multiphase A.C. sources, comprising the steps of:
- initially connecting said load to one of said first, second and third power sources;
- detecting a condition requiring transfer of said load to another of said first, second and third power sources;
- and
- upon detection of said transfer condition, transferring said load to another of said first, second and third power sources based upon a predetermined order of priority among said power sources.
Dependencies are inferred from the claim text.