thank you everyone ...
MarkT ; about "the diode on the output of the relay" ... "You could put it across the motor terminals to reduce arcing on the relay contacts though"
that's what i wanted to do but .. i didn't put the diode at the right place ... i changed my schematic ... is it the right place ?
thk U Graynomad and Terry King for the relay board ... I will look at the product.