Arranque Estrella Triángulo de Motor Trifásico CADESIMU

Star-Delta Starting Method for Three-Phase Motors

Overview of Components Needed

• To implement the star-delta starting method, a three-phase motor with six terminals is required, along with a three-phase power supply, thermal protection, and specific contactors.

• Essential components include:

• Star contactor

• Delta contactor

• Thermal relay

Circuit Wiring Steps

• The circuit must be wired to connect the delta contactor and the star contactor properly. The motor's coils (W2, U2, V2) should also be grounded.

• For the control circuit:

• Connect line and neutral power supply.

• Include thermal protection and both normally closed and open contacts from the thermal relay.

Control Mechanism for Motor Start

• A normally open auxiliary contact is needed for self-holding of the line contactor; this connects in parallel with the start button to ensure simultaneous activation of both line and star contactors.

• After starting in star configuration, a timer switches from star to delta after a predetermined time.

Benefits of Star Configuration

• The star configuration allows for a smoother start by reducing starting voltage and torque current. This prevents abrupt starts that could damage equipment.

• Once the motor reaches over 75% speed, as controlled by a timer, it disconnects from the star configuration to operate at nominal voltage through delta connection.

Timer Integration and Safety Features

• A delay timer is necessary for switching connections; it should be connected in parallel with the coil of the star contactor to prevent simultaneous energization of both configurations.

• Cross-locking using normally closed contacts ensures additional safety by preventing accidental energization.

Labeling Components and Testing Circuit Functionality

• Components are labeled as follows:

• K1: Line Contactor

• K2: Delta Contactor

• K3: Star Contactor

• S1: Stop Button

• S2: Start Button

This labeling aids in troubleshooting during testing phases.

Pilot Lights Implementation

• Pilot lights are integrated into the system to indicate when the motor is running or if there’s an overload fault; these are connected via normally open contacts from the thermal relay. The fault indicator light should be red for visibility.

Testing Procedure

• Upon activating the circuit:

• Engage circuit breaker.

• Press start button; observe activation of line and star contactors.

• After countdown from timer, confirm switch to delta configuration occurs smoothly without issues.