Potential dividing method

Fall of potential method

Fall of resistance method

Current dividing method

AC is easily available

Protect the coils in the meter

Reduce the value of current in the meter

Avoid the effect of electrolytic Emf interference

One primary winding

Two primary windings

Three primary windings

Four primary windings

Control the fault circuit current

Protect the residual current

Protect the equipment from over load

Protect the circuit from short circuit