What is single section preventer?
Single-phase preventer is employed to guard the induction motor from single phasing fault. Single phasing could be a terribly dangerous fault to the electrical motor and that damages the motor mechanical device winding apace. … the one phasing results in unbalanced current within the motor mechanical device.
Single Phase Preventer Working Principle:
Single-phase preventer is employed to guard the induction motor from single phasing fault. Single phasing could be a terribly dangerous fault to the electrical motor and that damages the motor stator coil winding quickly. Generally, single phasing is nothing however a motor runs once in a veryll|one amongst|one in every of} the provision is disconnected because of circuit or improper contact in a switch or alternative electrical instrumentation failures. Normally, the motor runs with the three-phase offer and that takes balance presently in every section winding. take into account one among the fuses has blown. however the motor still in rotating position that tries to rotates at a similar speed. At that very same time, the absence section current is going to be shifted to the remaining live phases. Therefore, the present within the alternative phases will increase up to three times its traditional worth instantly. this is often known as single phasing fault.
The single phasing results in unbalanced current within the motor stator coil. The element that is a gift during this unbalanced current known as negative sequence element. This negative sequence element creates the magnetic flux opposite to the most flux. This leads to double frequency currents to induce within the rotor to cause its heating.
Current sensing Single Phase Preventer:
Current sensing single section preventer works sort of a negative sequence relay. It provides protection up to motor terminals. It operates on the principle of sensing negative sequence elements of the system. differing kinds of relay manufacturer provide addition operate like reverse phasing, unbalance provide and underneath voltage /over voltage trip thereupon single section preventer.
Single Phasing Preventer Working Principle:
The three-number of a current electrical device is placed in every part of the facility provide. The output of this electrical device is given to the negative sequence filter circuit and that sense the magnitude of unbalance. The filter circuit is going to be connected to the feedback circuit. The feedback circuit sends the trip command to the electrical fuse if the negative sequence current exceeds the predetermined price. If the failure of a single-phase the unbalances current flow within the motor and therefore the current is going to be perceived by the negative sequence filter. Then the management unit sends the trip command to the electrical fuse or another motor analytic mechanism.