In principle sounds sensible. make sure the contactor is rated for an inductive load, not just a resistive one - the inrush on some motors when starting under load, as pumps do, can be impressive so under rated contacts can have a short and brutal life. You many need a snubber across the contacts. I assume as part of what you have already done the supply and its earthing etc is adequate.

If automating a system that was previously supervised, consider what happens to the clock if there is a power cut or something jams, and if any sort of fail safe is needed. - for example on things filling tanks that may overflow when unattended you may need  level switch or an alarm of some kind. But it may well not be that sort of system at all.

Mike.

thanks for reply

thanks for reply