It is a single phase AC motor, 100W approx, so we are only planning to use a simple relay for on/off.
Can you get split wound contactor coils? This might be the solution for another application where we would like to use the same contactor for larger (5-11kW) pump motors, and which will operate on American 3ph (460V) and European 3 ph 380V.
Having to fit differing coils and/or different contactors becomes a logistical nightmare.