Contrel Elettronica Srl

TCB

• Sealable cover of standard series

• Different features can be made upon request

• Fixing: on the wall, on a cable / through bar or on a DIN bar using accessories supplied with the TA (depending on the model)

MEASURE TRANSFORMERS

The short circuit on the terminals or the earth connection can be made using the double fast-on or by wiring two wires on the same terminal.

PROTECTION TRANSFORMERS

The current transformer used as a current generator for protection relays has electrical characteristics different from those of the measuring transformer.

In fact, the measurement CT requires a saturation of the magnetic circuit with primary currents P5 In; while for the protection CT it is necessary that the value of the secondary current follows the increment of the primary current up to 10, 15 or 20 In so as to guarantee the intervention of the relay to the expected fault current.

It is important not to load the CT with a P performance higher than the one indicated to avoid changing the saturation value of the CT.

P = RI2 where:

P = load on the TA

R = resistance of the relay + resistance of the cables

I = rated secondary current of the CT

TRANSFORMERS DUAL REPORT

Double ratio on the secondary:

S1-S2 lower ratio, S1-S3 greater ratio.