What is the difference between marine motors operating in dual voltage mode?

In many marine motor applications, the marine motor is required to operate in dual-voltage mode, that is, the same marine motor can operate normally at different rated voltages, such as common 380/660V, 6/10kV dual-voltage marine motors. The direct factors that determine the rated voltage of a marine motor are the insulation level of the winding and the current density of the conductor. Some netizens asked: For dual-voltage marine motors, will different voltages cause problems with the marine motor windings? In response to netizens’ questions, we would like to share with you the essence of normal operation of dual-voltage marine motors. Voltage doubling marine motors refer to the different rated line voltages of three-phase motors under different wiring methods. When the marine motor adopts star connection, the rated voltage of the marine motor is higher; when the marine motor adopts delta connection, the rated voltage is lower; but the rated voltage corresponding to the two connection modes must meet a certain quantitative relationship, that is The rated line voltage of the star connection is three times the rated line voltage of the delta connection, and the rated line current of the delta connection is three times the rated line current of the star connection. Under the two wiring methods, the rated current and rated voltage are very different, but they will not have any adverse effects on the marine motor windings. The essence of this is the relationship between the phase value and the line value of the three-phase motor. The reliability of marine motor winding insulation performance and conductor current density depends on the phase voltage and phase current of the winding. When the marine motor is connected in delta, only the line voltage input to the marine motor is changed. According to the voltage relationship between the two wiring methods, when the marine motor uses star wiring and the root of the rated line voltage three times that of the delta wiring is applied, the phase voltage and phase current of each phase of the marine motor winding do not change; In the same way, for marine motors originally connected in star connection mode, when using delta connection mode, the voltage must be reduced according to the voltage relationship between the two connection modes to ensure the safety of the marine motor operation. According to the application practice of marine motors, three-phase asynchronous motors mostly use dual-voltage motors, that is, a higher voltage is used during the starting process of the marine motor, and a low-voltage delta connection is used during normal operation of the marine motor; of course, dual-voltage motors can meet different input power supply voltages for normal operation (the connection method must correctly match the voltage).