Current transformer IB-50

instrumentdryinterior

PROTECTIVE CURRENT TRANSFORMER Dimensions - 105 x 76 x 50 mm Primary bar - 30 x 10 mm Round conductor - ⌀ 23 mm While measurement current transformers are used to go into saturation above the nominal current range (shown in the excess current limiting factor FS) to prevent the increasing of the secondary current in case of system fault (e. g. primary short circuit) and to protect the equipments in the secondary circuit, a protective c.t. is used to have a saturation far away from its nominal current range in order to protect the switchgear etc. by using distance relays, overcurrent relays etc. Rated accuracy classes are 5P and 10P. "P" means "protection". The excess current limiting factor (in %) is given behind the precision class. It means e.g.10P5, if the primary current is five times higher than the nominal current, the negative deviation of the secondary current from the theoretically secondary current calculated by the ratio is not more than 10%. Application Protective current transformers convert an alternating current of high value into a lower, proportional one, in order to protect an installation by means of standard relays of rated currents 5 or 1A. These current transformers are suitable for indoor use in low-voltage networks. They are built according to UNE-EN and IEC 61869-2.