Technical Specifications

FAQ

1. What is the main function of the Schneider ATS490C25Y soft starter?

The Schneider ATS490C25Y is a 250 A Altivar Soft Starter designed to provide controlled starting and stopping for three-phase asynchronous motors. It uses torque control to manage the motor acceleration process, helping prevent the high electrical current and mechanical shock normally associated with direct-on-line starting. By progressively controlling motor torque, the ATS490C25Y can reduce stress on the electrical supply while providing smoother acceleration for the driven machine. It is intended for demanding process and infrastructure applications and can be used with pumps, fans, compressors, conveyors, mixers, crushers, and other industrial equipment. In addition to soft starting, the unit provides motor protection, internal bypass, communication capabilities, condition monitoring, and Safe Torque Off functionality, making it suitable for integration into industrial automation and motor-management systems.

2. What is the rated current of the ATS490C25Y?

The ATS490C25Y has a normal-duty rated operational current of 250 A when installed in the motor supply line under the specified operating conditions. For heavy-duty applications, the rated current is 210 A at 40°C. This distinction is important because the required soft starter rating depends not only on the motor’s nominal current but also on how the motor is operated. Applications involving high starting torque, long acceleration periods, or frequent starting cycles may require the heavy-duty rating to be considered. The motor nameplate current should always be compared with the applicable ATS490C25Y current rating. Selecting the device only from the motor’s kW rating can result in an unsuitable configuration, particularly when the motor operates under demanding mechanical loads.

3. What motor power can the ATS490C25Y handle?

The applicable motor power varies according to supply voltage, duty class, and connection method. For normal-duty applications in the motor supply line, the ATS490C25Y supports typical motor powers of 75 kW at 230 V, 132 kW at 400 V and 440 V, 160 kW at 500 V and 525 V, 220 kW at 660 V, and up to 250 kW at 690 V. Under heavy-duty conditions, the corresponding values are approximately 55 kW, 110 kW, 110 kW, 132 kW, 132 kW, 160 kW, and 200 kW respectively. Inside-delta connection can provide different motor power ratings depending on the supply voltage. Final selection should be based primarily on motor rated current and the actual starting requirements. Motor inertia, load torque, acceleration time, starting frequency, ambient temperature, and duty cycle should all be evaluated before selecting the operating configuration.

4. How does the ATS490C25Y control motor starting current?

The ATS490C25Y uses torque control to regulate the motor during acceleration, allowing the motor torque and current to increase in a controlled manner rather than producing the large instantaneous current associated with direct-on-line starting. Its current limiting function can be configured from 150% to 700% In, with a maximum of 5 × Ie. Proper adjustment of this parameter can help reduce voltage disturbances on transformers, generators, cables, and other equipment connected to the same electrical system. Controlled torque also reduces sudden mechanical loading on shafts, couplings, gearboxes, belts, pumps, and other transmission components. However, the current limit must be high enough to provide sufficient starting torque. If it is set too low for the actual load, the motor may accelerate slowly, fail to reach operating speed, or trigger excessive acceleration-time and thermal protection functions.

5. What communication protocols are supported by the ATS490C25Y?

The ATS490C25Y supports Modbus Serial, Modbus TCP, and EtherNet/IP communication. The serial interface uses a two-wire RS-485 connection, while Ethernet communication is provided through a 100BASE-TX interface using an RJ45 connector. Modbus Serial communication supports transmission rates from 4.8 to 38.4 kbps, with device addresses from 0 to 247. These communication functions allow the soft starter to be integrated with PLCs, HMIs, SCADA systems, industrial computers, and other automation equipment. Operating commands, motor status, measured values, alarms, faults, and diagnostic information can be exchanged through the communication network. When commissioning the communication system, technicians should verify the device address, baud rate, parity, stop bits, RS-485 wiring, Ethernet configuration, and PLC communication parameters. A communication fault should be diagnosed separately from a motor or power-stage fault.

6. What protection functions are available on the ATS490C25Y?

The ATS490C25Y provides a broad range of protection functions covering both the motor and the soft starter. These include mains phase failure, starter thermal protection, motor thermal protection, motor overload, motor underload, excessive acceleration time, motor phase-loss detection, mains phase inversion, external motor thermal protection, inside-delta wiring protection, and protection against short circuits between motor phases and earth. Motor thermal protection uses a Class 10E characteristic and is intended to help prevent excessive thermal loading during abnormal operation. These functions allow the soft starter to detect and respond to many common motor-control problems. However, integrated protection does not replace correctly selected upstream circuit breakers, fuses, short-circuit protection, grounding, or cable protection. The protection settings should also be configured according to the actual motor nameplate data and process requirements.

7. What is the purpose of the internal bypass in the ATS490C25Y?

The internal bypass allows the ATS490C25Y to reduce semiconductor losses once the motor has completed its controlled acceleration and reached stable running conditions. During starting, the power electronics regulate the motor current and torque. After normal operating speed is reached, the internal bypass provides a lower-loss current path, reducing continuous heat generation within the power stage. This is particularly useful for larger motors that operate for extended periods because it helps reduce the thermal load associated with continuous semiconductor conduction. The bypass is managed by the soft starter’s internal control system and should not be treated as a simple replacement for an external contactor. Proper installation, control configuration, electrical protection, and commissioning are still required to ensure reliable operation during the transition from controlled starting to normal running.

8. How should the ATS490C25Y be troubleshot if the motor does not start or repeatedly trips?

Troubleshooting should start with the incoming three-phase supply and the 110–230 V AC control supply. Confirm that all three phases are present, the voltage is within the permitted range, and the control circuit is correctly energized. Next, check the motor connection, motor nameplate current setting, power cables, terminals, start and stop commands, and all external interlocks. If a phase-failure or phase-loss alarm occurs, inspect the upstream contactor, circuit connections, terminals, motor cables, and motor windings. If an overload or thermal alarm occurs, check the actual motor current, mechanical load, acceleration time, starting frequency, ventilation, and ambient temperature. If the motor starts but cannot reach its normal operating speed, examine the current-limit setting, starting torque, acceleration time, and load inertia. For pumps, fans, compressors, and other process equipment, the mechanical process should also be checked because an abnormal load can significantly increase starting requirements. For network-controlled systems, verify Modbus or Ethernet communication parameters, PLC commands, device addressing, and communication status. Diagnostic information should be reviewed before replacing the soft starter, because repeated trips can often be caused by incorrect parameters, excessive mechanical load, unstable power, incorrect wiring, or unsuitable duty settings rather than a defective ATS490C25Y.