THE MOTOR SPEED IS STILL QUITE LOW THE ROTATING GENERATOR COAXIAL WITH THE ROTOR GENERATES AN ELECTR

The YVF2 SERIES FREQUENCY CONVERSION SPEED SPECIAL THREE – PHASE ASYNCHRONOUS MOTOR (with brush) started by the YVF2 SERIES FREQUENCY CONVERSION SPEED SPECIAL THREE – PHASE ASYNCHRONOUS MOTOR method is to add a damping winding on the rotor of the synchronous motor, also known as the starting winding. When the motor starts, it is the same as the asynchronous motor. When the motor speed reaches 95% of the rated speed, the DC excitation current is added to make the synchronous motor run in a synchronous mode. This kind of starting method is limited by the capacity of the power grid, so it can be divided into full-voltage starting and reduced-voltage starting.

No matter what method is used to start the brushed motor, it is required that there is no DC excitation magnetic field in the magnetic field when the synchronous motor is started. Otherwise, when the motor starts, the magnetic flux of the magnetic field is nearly saturated, which will make the motor difficult to start. The synchronous motor used in the SP system of the semi-submersible ship is started by the asynchronous motor. If the motor is a permanent magnet motor according to the information provided by the manufacturer, the magnetic field of the motor is nearly saturated before starting, and the rotation generated when the motor starts asynchronously. The magnetic field is not enough to drive the motor to run. According to this analysis, the motor’s rotation should be made of high-coercivity materials. Since the motor is brushless, it can be determined that the motor works in a self-excited rectification mode.

Influenced by the motor structure of the SP system, the starting process of the motor is different from the asynchronous starting process of the conventional synchronous motor. During the starting process of the motor, there are stator excitation magnetic field and asynchronous rotating magnetic field induced by the rotor in the motor magnetic field, and there is also DC. Excited synchronous magnetic field. The synchronous motor with ordinary asynchronous start is only added to the synchronous excitation current when the motor speed reaches 95% of the rated speed. The motor of the SP system is in operation, the motor speed is still quite low, and the rotating generator coaxial with the rotor generates an electric potential. After the static rectifier, a DC excitation magnetic field is generated in the synchronous motor.