Without any specific data its hard to be accurate, but the following must be held in mind. With an AC driven contactor "out" the magnetic path is broken by an air gap so when the voltage is applied, there is a big inrush current. When the contactor pulls in the magnetic path is complete so the current falls to 10% of the pull-in current. With DC the current is the same, in or out so if the contactor coil is not to over heat an "economy" resistor must be switched into the circuit. This is often done by using an auxially contact that is normally closed when the contactor is de-energised. To use on AC/DC, use a bridge rectifier and a smoothing cap so your "AC" is DC .
Frank