MR And PR Current Transformers

PRSeries:
Protective current transformers are required to operate over a range of current many times the circuit rating and is frequently subjected to conditions greatly exceeding those which it would be subjected to as a measuring current transaformer. When a current transformer is used to energise a protective relay, it must maintain its characteristic ratio up to some multiple offered rated current. This multiple, may be 5, 10, 20 or some even higher value and is know as the Accuracy Limit Factor(ALF). Therefore, the selection of Protective Current Transformers in relation to accuracy class and ALF require a close examination of relay characteristic and circuit conditions which includes the relay burden and the pilot wire lead burden.

Primary current: 30A-5000A
Secondary current: 5A, 1A
Standard approval: BS7626, IEC185
Maximum voltage: 0.72KV
Frequency: 50/60 Hz
Rated load: 5VA-15VA
Class: 1.0 3.0
Short-time thermal current: Ith=60 X Ih
Rated security coefficient: FS<5

MR Series:

Protective current transformers are required to operate over a range of current many times the circuit rating.