As the design of the cooling system directly affects the reliability of marine motors, it is necessary to evaluate the influence of the cooling system on the motor.

Taking a high-power-density marine motor as an example, an overall model of the motor is established using the electronic thermal simulation software ANSYS Icepak, and the 3D temperature fields of three typical heat dissipation systems of the axial water jacket, spiral water jacket and annular water jacket are calculated. The cooling effects of the components and temperature gradients are then compared and evaluated, and an optimal scheme based on a combination of forced air-cooling and water-cooling is proposed.

The calculation results show that the water-cooling system can solve the heat dissipation problems of the casing and stator, and reduce the axial and circumferential temperature gradients. The annular water jacket works best. However, the water-cooling system has a poor effect on the rotor and end casing. After optimization, the rotor temperature and overall temperature gradients of the motor are greatly reduced.

The annular water jacket is recommended to be chosen as the water-cooling system for marine motors, and an auxiliary cooling system should be considered to make up for the defects of the water-cooling system.