Ocean ferry

If a fuel powered generator is used, it is AC power. If battery power is used, it is direct current. Large ships use generators. The generator operates based on the principle of electromagnetic induction, where the coil periodically cuts magnetic induction lines in a magnetic field. During each cycle, the magnitude of the current changes four times and the direction changes twice, making it an alternating current.

Three phase asynchronous motors are used for marine propulsion, applied to ships for lateral propulsion of the hull. It has the characteristics of high starting torque, low starting current, and frequent starting, and belongs to the field of motor technology.

Due to the fact that the starting current of a regular squirrel cage three-phase asynchronous motor is 57 times the rated current, the starting torque is 1 0 1.  5 times, the starting current will cause a significant impact on the ship's power grid, and the starting torque cannot meet the requirements of the ship's side push.

Furthermore, it may cause sudden tripping of the ship's power grid, rendering other ship equipment unable to function properly, greatly reducing the reliability of the ship's operation. Therefore, there is an urgent need to develop a new type of three-phase asynchronous motor for marine lateral thrusters. The new type of marine lateral thruster uses a three-phase asynchronous motor, which requires the starting current of the motor to be reduced to 4% of the rated current Less than 5 times, and the starting torque can reach more than 2 times the rated torque.