Contactor inrush peaks can reach 10 to 20 times the required holding current. This leads to the transformer being oversized in relation to the continuous power it has to
supply. The transformer must be sized so that the voltage drop at its terminals, caused by the inrush, remains with the permissible limits for the contactor to close
properly.The two power values that need to be taken into account to determine which transformer rating to use are therefore:
a) The continuous power the transformer has to supply
b )The maximum inrush power it has to provide
In practice, only the sum of the holding currents and the largest contactor inrush
current need to be considered.
Please check attached document for selection sheet
supply. The transformer must be sized so that the voltage drop at its terminals, caused by the inrush, remains with the permissible limits for the contactor to close
properly.The two power values that need to be taken into account to determine which transformer rating to use are therefore:
a) The continuous power the transformer has to supply
b )The maximum inrush power it has to provide
In practice, only the sum of the holding currents and the largest contactor inrush
current need to be considered.
Please check attached document for selection sheet
Released for:Schneider Electric India
