Technical Specifications

FAQ

1. What is the Schneider ATS490C21Y soft starter used for?

The Schneider ATS490C21Y is a 210 A Altivar Soft Starter designed for controlling the starting and stopping of three-phase asynchronous motors. It is intended for industrial process and infrastructure applications where direct-on-line starting may cause excessive electrical current, mechanical shock, or unstable acceleration. The soft starter uses torque control to manage the motor during acceleration and deceleration, allowing the motor to reach operating speed in a controlled manner. This makes it suitable for pumps, fans, compressors, conveyors, mixers, crushers, grinders, cutters, and other demanding machinery. The ATS490C21Y also provides integrated motor overload protection, internal bypass, condition monitoring, communication capabilities, and Safe Torque Off. These functions allow it to operate as part of a larger automation and motor-management system rather than simply serving as a starting-current limiter.

2. What is the rated current of the ATS490C21Y?

The ATS490C21Y has a rated operational current of 210 A. This current rating is one of the most important parameters when selecting the soft starter for a motor because the motor’s nominal current must not exceed the applicable operational current rating of the soft starter. The correct selection also depends on the application duty, acceleration time, starting frequency, motor characteristics, and load requirements. A motor with a lower nominal current can generally be used with the ATS490C21Y when the application parameters are correctly configured. However, simply selecting the soft starter based on motor power in kW is not sufficient. The motor nameplate current and actual starting conditions should be checked first, particularly for high-inertia loads or applications requiring frequent starts.

3. What supply voltage is supported by the ATS490C21Y?

The ATS490C21Y supports a three-phase AC motor supply from 208 V to 690 V at 50–60 Hz. This broad voltage range allows the same model to be used in different industrial electrical systems. The control circuit uses a separate 110–230 V AC supply at 50–60 Hz. Before commissioning, the installer should verify both the main power supply and the control supply because the two circuits have different requirements. The incoming three-phase voltage should be checked phase-to-phase, while phase sequence and motor wiring should also be verified. If the installation has a generator or transformer with limited short-circuit capacity, the starting-current settings should be reviewed carefully because the motor starting process can cause temporary voltage disturbances.

4. How does the ATS490C21Y reduce motor starting current?

The ATS490C21Y uses controlled torque starting to regulate the electrical power supplied to the motor during acceleration. Instead of allowing the motor to draw a large inrush current immediately, the soft starter progressively controls the motor’s electrical conditions so that torque develops in a controlled way. The current limit can be adjusted from 150% to 700% In, with a maximum of 5 × Ie. Proper adjustment can reduce the electrical impact of motor starting on transformers, generators, cables, and other connected loads. It also helps reduce mechanical shock in the driven system. However, the current limit should not be set unnecessarily low. If insufficient current is available to overcome the load’s starting torque and inertia, the motor may accelerate very slowly, remain below operating speed, or eventually trigger an excessive acceleration-time or thermal protection function.

5. What communication functions are available on the ATS490C21Y?

The ATS490C21Y provides Modbus Serial, Modbus TCP, and EtherNet/IP communication capabilities. The serial communication interface uses a two-wire RS-485 connection, while the Ethernet interface uses 100BASE-TX communication through an RJ45 connector. Modbus Serial transmission rates range from 4.8 to 38.4 kbps, with addresses from 0 to 247. These interfaces allow the soft starter to communicate with PLCs, HMIs, SCADA systems, industrial computers, and other automation equipment. Operating commands, status information, measurements, alarms, faults, and diagnostic data can be exchanged through the communication system. During commissioning, the communication address, baud rate, parity, stop bits, cable wiring, Ethernet configuration, and PLC communication parameters should be checked systematically. A communication failure does not necessarily indicate a problem with the power section or motor-control function.

6. What protection functions are integrated into the ATS490C21Y?

The ATS490C21Y includes a comprehensive range of protection functions for both the motor and the soft starter. These include mains phase failure, starter thermal protection, motor thermal protection, motor current overload, motor underload, excessive acceleration time, motor phase-loss detection, mains phase inversion protection, external motor thermal protection, internal-delta wiring protection, and protection against short circuits between motor phases and earth. Motor thermal protection uses a Class 10E characteristic. These functions allow the soft starter to respond to abnormal operating conditions before they cause more serious damage to the motor or power circuit. Nevertheless, integrated protection should be used together with properly selected upstream circuit breakers, fuses, grounding systems, motor cables, and other electrical protection equipment. Protection settings should also be matched to the motor nameplate and actual process conditions.

7. What is the purpose of the internal bypass in the ATS490C21Y?

The internal bypass allows the ATS490C21Y to reduce losses after the motor has completed its controlled starting process and entered normal operation. During acceleration, the power semiconductor stage regulates the motor current and torque. Once the motor reaches stable running conditions, the internal bypass provides a lower-loss path for the operating current. This helps reduce heat generation inside the soft starter during continuous operation and can improve overall system efficiency. The bypass is controlled automatically by the soft starter’s internal control system and should not be treated as a basic external contactor. Correct wiring and configuration are still required. During commissioning, it is useful to verify that the unit completes acceleration correctly, transitions to normal running, and does not produce unexpected thermal or electrical alarms during bypass operation.

8. How should the ATS490C21Y be troubleshot if a motor fails to start or repeatedly trips?

Troubleshooting should begin with the incoming three-phase supply and the 110–230 V AC control supply. Check that all phases are present, the voltage is within the permitted range, and the control circuit is correctly energized. Next, verify the motor’s wiring, connection method, nameplate current, start command, stop command, and all external interlocks. If a phase-failure or motor phase-loss alarm occurs, inspect the upstream contactor, terminals, cables, motor terminals, and motor windings. If an overload or thermal alarm occurs, check the actual running current, mechanical load, motor cooling, acceleration time, starting frequency, and ambient conditions. If the motor starts but cannot reach full speed, examine the current-limit setting, initial torque, acceleration time, and load inertia. For pumps and fans, the process conditions should also be checked because excessive hydraulic or mechanical resistance can increase the starting requirement. If the ATS490C21Y is controlled through Modbus TCP, EtherNet/IP, or Modbus Serial, communication settings and PLC commands should be checked separately. Persistent faults should be analyzed using the stored diagnostic information before replacing the soft starter, as many apparent starter faults are actually caused by incorrect parameters, external wiring, abnormal loads, or unstable power supplies.