- Overload protection with adjustable current and time
- Short circuit protection with adjustable current and time
- Earth fault protection with adjustable current and time
- Instantaneous protection
- Switchable thermal reflectivity (for recurrent faults in over load zone)
- Terminals for fault signals
- Switchable overload protection on neutral with choice of 50% / 100% Ir setting
Thermal reflectivity is an enhancement of “thermal memory” feature, which ensures that the breaker trips progressively faster on recurrent overloads. When overloads happen in succession, there is no cooling time available for cable insulation. This can lead to insulation failure. Hence, the feature can be described as:
a. Assume there was an overload of X magnitude and as per selected curve, the breaker will trip in less than 20 seconds.
b. On recurrent overload, the breaker will trip in less than 20 seconds
c. On subsequent, overloads, the breaker will continue to trip earlier and earlier.
* If the time duration between two overloads is less than one hour, it is considered as a recurrent overload.
* Auxiliary supply
After tripping of ACB, protection and control unit does not have a power supply.
In this case auxiliary power supply can help P&C unit to give an indication signal.