Hi that will depend on 1) three phase tension 2) the nominal voltage of the pump If the three-phase voltage and the nominal voltage of the pump are equal, for example three-phase voltage = 3 × 220V, nominal voltage of pump = 220V, then you must take 2 phases of the three present If the three-phase voltage is 1.73 times higher than the nominal voltage of the pump, for example three-phase voltage = 3 × 380V, nominal voltage 220V, then you should take any more neutral phase. If the neutral is not available, you should ask the company to download or place a 380 / 220V transformer, which may be more economical to replace the motor with another three-phase Cheers