Question { Electrotherm, 5661 }

how snubber circuit works to protect switching devices?

Answer

A snubber is a device used to suppress ("snub") a phenomenon such as voltage transients in electrical systems.Snubbers are frequently used in electrical systems with an inductive load where the sudden interruption of current flow leads to a sharp rise in voltage across the current switching device.It will act as bypass and protects sytem

Question { 8710 }

What is the difference between Zero Current Transformer and
Core Balance CT ?

Answer

Core Balance Current Transformers
The CBCT or the Core Balance Current Transformer is a current transformer is used for earth fault protection in grounded three phase systems. It is also known as the zero-sequence current transformer. The CBCT is a current transformer through all the three phases are made to pass as in the diagram. Thus the magnetic fluxes caused by the three phase currents cancel each other.

The net resultant flux being zero does not induce any current in the secondary of the transformer. Thus the secondary current of the core balance current transformerwhen all the three phases are healthy is zero.

When an earth fault occurs in one of the phases, the zero-sequence fault current which flows is not cancelled by the flux of the other two phases and hence induces a current in the secondary.

The core balance current transformer can be connected to an earth fault relay which can be used to generate the tripping signal