How do I change the motor orientation in a star triangle connection?

Encyclopedia
09/28/2024

In a Star-Delta or Y-delta connection, changing the direction of the motor can be achieved by changing the phase sequence applied to the motor windings. The direction of the motor depends on the power supply phase sequence, that is, the order in which the three phases of the power supply reach the motor winding. The following are the specific operation steps and principles:


Star connection (Star/Y connection)


Star connection principle: In a star connection, one end of the three windings is connected together to form a common point (called a neutral point), while the other end is connected to the three phases of the power supply. The connection mode of the motor winding determines the influence of the phase sequence of the power supply on the rotation direction of the motor.


A way to change direction


To change the direction of the motor, the connection sequence of any two windings can be switched. For example, if the original connection order was U-V-W (assumed to be clockwise), you can change the connection order to U-W-V or W-U-V (counterclockwise).


Delta connection (Delta/ Delta connection)


Triangular connection principle: In a triangular connection, three windings are connected end to end to form a closed loop, and one end of each winding is connected to one of the power supply. The triangular connection also depends on the power supply phase sequence to determine the direction of rotation of the motor.


A way to change direction


In a triangular connection, the direction of the motor can also be changed by swapping the connection sequence of any two windings. For example, if the original connection order was U-V-W, you can change the connection order to U-W-V or W-U-V.


Specific operation steps


  • Power off: Before performing any operation, ensure that the motor has been powered off and confirm that there is no residual voltage.


  • Mark the wiring: Before changing the wiring, mark the wiring position of the original each winding to prevent confusion.


  • Disconnect: Disconnect the connection between the motor winding and the power supply.


  • Reconnection: Exchange the connection sequence of any two windings. For example, if the original connection was U-V-W, you can change it to U-W-V or W-U-V.


  • Check cable connections: After reconnecting, check that all cables are correct.


  • Test: Re-power the motor and observe whether the rotation direction of the motor meets the expectations. If the direction is not correct, adjust the wiring sequence again.



Matters needing attention


  • Safety first: Before any electrical operation, be sure to ensure safety, including but not limited to power off, power inspection and other steps.


  • Motor model: Different motors may have different wiring methods, so before changing the wiring sequence, you should consult the motor manual or technical data.


  • Control circuit: If the motor is equipped with a frequency converter (VFD) or other controller, then changing the direction of the motor may need to be achieved through the controller Settings, rather than directly changing the wiring sequence of the motor windings.


Sum up


The key to change the motor direction in the star triangle connection is to adjust the phase sequence of the power supply. By exchanging the connection sequence of any two windings, the rotation direction of the motor can be changed. Whether it is a star connection or a triangle connection, the principle is the same. Ensure that safety procedures are followed during operation and that cables are carefully checked to prevent equipment damage or safety accidents caused by incorrect connections.


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