The present study has been conducted thermal characteristics of 210 kW interior magnet synchronous motor (IPMSM) with two-channelled helical water cooling device using the three-dimensional finite element method (FEM). The numerical analysis was carried out by changing the flow velocity of the coolant in the cooling channels to identify the effect of laminar and turbulent flow. By keeping the temperatures of the NdFeB magnet, windings under the allowable temperature limits with two-channelled water cooling channels, this paper proposes the validation of the water cooling channel of the IPMSM.