4. Replacement and Adjustment
Breaker Switch
4
Key to Acronyms
TR
Transformer
TC
Trip Coil
ZCT
Zero Cross Terminal
R
Resistance Test Switch
M
Load Device
Ig
Current Leakage
The breaker switch mechanism consists of a ZCT (Zero Cross Terminal), a sensor inside the breaker switch
unit checks the amplified signals from a detection device.
The main power supply line runs through the ZCT. The ZCT generates a signal if it detects any fluctuation
in the power supply caused by a short circuit.
Normally, the current phase is zero and the breaker does not operate.
When a short circuit occurs:
• The current leakage (Ia + Ib Ic = Ig) flows.
• Voltage is generated at the secondary winding.
• The amplitude of the detection device increases
404