2Y- connection two-speed motor contactor control circuit of the four

The circuit depicted in Figure 3-99 illustrates a low start-up mechanism for a motor, which transitions to high-speed operation automatically. The start-up process is facilitated by a shaped connection, while the transition to high-speed operation is managed by a 2Y-connector. The duration of the acceleration from low to high speed can be adjusted using time relay KT. Additionally, the circuit includes a low-speed start button labeled SBi.

The circuit operates by initially applying a lower voltage to the motor, allowing for a gradual increase in speed. This is particularly useful in applications where sudden starts can cause mechanical stress or where a gradual ramp-up is necessary for operational safety. The shaped connection serves to limit the initial current, ensuring that the motor does not draw excessive power at start-up.

Once the motor reaches a predetermined low-speed threshold, the time relay KT activates, allowing the circuit to switch to the high-speed operation mode. The timing of this transition can be fine-tuned according to the specific requirements of the application, providing flexibility in operational performance.

The low-speed start button SBi serves as a manual control mechanism, enabling the operator to initiate the motor's start-up process at a low speed. This feature is particularly beneficial in scenarios where precise control over the motor's acceleration is necessary, such as in conveyor systems or pumps where load conditions may vary.

Overall, the design of this circuit not only enhances the longevity of the motor by preventing abrupt starts but also optimizes the operational efficiency by allowing for adjustable acceleration times. The integration of these components ensures that the motor operates smoothly across its speed range, thereby improving reliability and performance in various applications. Circuit shown in Figure 3-99. The low start-up circuit to the motor ( shaped connection), then automatically accelerated speed into high speed (2Y-connector) operation. Start f rom low to high speed running interval can be adjusted time relay KT. Figure, SBi low speed start button.