IEC 60947-6-1:2021 pdf download.Low-voltage switchgear and controlgear
3.3.4 automatic transfer switching equipment
ATSE
self-acting transfer switching equipment, including all necessary sensing inputs, monitoring,and control logic for transferring operations
Note 1 to entry: ATSE can have a feature for local and/or remote and/or manual operation.
3.3.5 derived transfer switching equipment
derived TSE
TSE based on switching devices tha ave certain tests required for compliance with
IEC 60947-6-1 as defined in Table 9, covered by IEC 60947-3 for Class PC, IEC 60947-2 or
IEC 60947-6-2 for Class CB, or IEC 60947-4-1 for Class CC
Note 1 to entry: It is not necessary to repeat tests fully covered in the switching devices product standards.
3.3.6 Class PC TSE
transfer switch equipment based on mechanical switching devices, that do not need electrical power to hold the main contacts open or closed and capable of making， carrying, and breaking currents under normal circuit conditions including operating overload conditions, and making and withstanding short-circuit currents
Note 1 to entry: For the purposes of this document, a fuse-combination unit is considered a Class PC device capable of breaking short-circuit current.
Note 2 to entry: Class PC TSE are also capable of withstanding conditional short-circuit currents.
3.3.7 Class CB TSE
transfer switch equipment based on mechanical switching devices and capable of making,carrying and breaking currents under normal circuit conditions including operating overload conditions, and making and breaking short-circuit currents
Note 1 to entry: Class CB TSE for which the manufacturer has assigned a short-time withstand current are also capable of withstanding short-circuit currents.
3.3.8 Class CC TSE
transfer switch equipment based on mechanical switching devices having only one position of rest, operating otherwise than by hand， and capable of making， carrying and breaking currents under normal circuit conditions including operating overload conditions
Note 1 to entry: Class CC TSE are not capable of making or breaking short-circuit currents. They are only capable of withstanding conditional short-circuit currents.
Note 2 to entry: Class CC TSE is not suitable for isolation.
3.4.5 contact transfer time
time measured from the mechanical opening of all poles from one set of main contacts of one power supply to the mechanical closing of any pole of a second set of main contacts on another power supply, with any adjustable time-delay set to the minimum value
Note 1 to entry: Contact transfer time does not apply to three- position MTSE.
3.4.6 operating transfer time
time measured from the instant when the transfer conditions are fulfilled to the closing of the main contacts on the other source, with any adjustable time delay set to the minimum value,transfer condition being typically supply deviations and programmed conditions for ATSE or remote control commands for RTSE
Note 1 to entry:Operating transfer times from source I to source II and from source II to source I can be different, and can vary depending on the monitored supply deviation.
Note 2 to entry: Operating transfer time does not apply to MTSE.IEC 60947-6-1 pdf download.