Technical Specifications

FAQ

1. What is the main function of the Schneider ATS48C66Q soft starter?

The Schneider Electric ATS48C66Q is a high-current Altistart 48 soft starter designed to control the starting and stopping of three-phase asynchronous motors. Instead of connecting the motor directly to the full supply voltage at startup, the ATS48C66Q gradually controls the motor’s electrical and torque conditions during acceleration.

The device uses Schneider Electric’s torque-control technology to provide a controlled starting profile. This can significantly reduce mechanical shock in applications where large motors drive pumps, compressors, conveyors, fans, or other heavy industrial machinery.

The ATS48C66Q also provides motor thermal protection, starter thermal protection and line phase-failure detection. It can therefore form part of the motor protection and control system rather than functioning only as a starting device. Its high-current design makes it particularly suitable for demanding industrial motor applications.

2. What motor power can the ATS48C66Q support?

The applicable motor power depends on the supply voltage, motor connection method and application duty. The ATS48C66Q can be connected either in the motor supply line or directly to the motor delta terminals, and these two configurations have different current and power capabilities.

At 230 V, the unit supports up to 160 kW for severe-duty applications when connected in the motor supply line, while standard applications using an inside-delta connection can reach up to 315 kW. At 400 V, the corresponding ratings include 315 kW for severe-duty in-line applications, 355 kW for standard-duty in-line applications, 400 kW for severe-duty inside-delta applications and up to 500 kW for standard-duty inside-delta applications.

Therefore, the maximum 500 kW figure should not be treated as a universal motor rating. The motor’s rated current, starting characteristics, load type, connection method and required starting duty must all be considered when selecting the ATS48C66Q.

3. What supply voltage and frequency are suitable for the ATS48C66Q?

The ATS48C66Q is designed for a three-phase supply voltage of 230–415 V AC, with an operating supply limit of approximately 195–456 V. The normal supply frequency is 50–60 Hz, with an applicable frequency range of approximately 47.5–63 Hz.

Before commissioning, the incoming supply should be checked against the motor nameplate and soft starter requirements. The phase sequence, voltage balance and continuity of all three phases should also be verified.

The motor connection must be configured correctly for the selected application. In-line and inside-delta connections have different current relationships, so the control and power wiring must correspond to the selected configuration. Incorrect voltage or connection settings can cause starting faults, excessive current, phase-related alarms or motor protection trips.

4. How does the ATS48C66Q reduce motor starting current and mechanical stress?

The ATS48C66Q controls the motor’s starting process instead of applying full line voltage immediately. Its torque-control starting method limits the starting current to approximately 5 × In while controlling the acceleration characteristics of the motor.

Reducing the sudden increase in current can help minimize disturbances to the electrical supply. At the same time, controlled torque reduces the mechanical shock that can occur when a large motor is started directly across the line.

This is particularly useful for equipment such as pumps, conveyors, compressors and large fans. Smooth acceleration can reduce stress on shafts, couplings, gearboxes and other mechanical components. In pump applications, controlled starting and stopping can also help reduce hydraulic stress associated with abrupt changes in flow and pressure.

The correct starting parameters still need to be selected according to the actual motor and load. If acceleration is configured too aggressively, the desired mechanical benefit may not be achieved. If acceleration is excessively long, the motor and soft starter can experience unnecessary thermal loading.

5. What protection functions are integrated into the ATS48C66Q?

The ATS48C66Q includes several protection functions for both the motor and the soft starter. Motor thermal protection monitors the thermal condition associated with motor operation, while starter thermal protection helps protect the internal power components from excessive thermal stress.

Line phase-failure detection is also provided. A missing phase can cause abnormal motor current and uneven operation, potentially resulting in motor overheating or unstable operation. Detecting this condition allows the soft starter to react before the motor continues operating under an abnormal supply condition.

The ATS48C66Q also provides diagnostic and relay output functions for conditions such as faults and completion of the starting sequence. These signals can be connected to a PLC, control panel or other supervisory equipment.

Protection settings should be matched to the actual motor nameplate information and application conditions. Incorrect settings can result in nuisance trips or insufficient protection, particularly in applications involving frequent starts or extended acceleration times.

6. Can the ATS48C66Q be integrated with a PLC or industrial communication system?

Yes. The ATS48C66Q provides an RS485 multidrop communication interface and supports Modbus communication. The communication connection uses an RJ45 connector, and supported transmission rates include 4800, 9600 and 19200 bps.

This allows the soft starter to exchange operating and diagnostic information with a PLC or other automation controller. Depending on the system configuration, the control system can monitor starter status, motor-related information, fault conditions and other available operating parameters.

When installing the ATS48C66Q on a Modbus network, the communication address, transmission speed and other communication parameters must be configured consistently with the network master. The RS485 wiring should also be installed correctly, including appropriate network topology and termination where required.

If communication fails while the motor and starter continue to operate normally, troubleshooting should begin with the communication parameters, cable, connector and network configuration rather than immediately investigating the power section.

7. Why might an ATS48C66Q trip during motor acceleration?

A trip during acceleration can have several causes, so the first step should be to identify the actual diagnostic or protection condition reported by the soft starter. The motor’s rated current, starting parameters, acceleration time and load characteristics should then be reviewed.

A mechanical load that requires excessive starting torque can cause the motor to accelerate too slowly. Pumps with abnormal operating conditions, conveyors with excessive load, compressors under pressure, or mechanically obstructed equipment can all create higher-than-expected starting requirements.

The electrical supply should also be checked for phase loss, voltage imbalance, insufficient voltage or incorrect wiring. The motor terminals and the selected in-line or inside-delta configuration should be verified carefully.

Thermal conditions are another important consideration. If the application requires frequent starts or long acceleration periods, accumulated heat can cause the soft starter or motor protection system to operate. In such cases, simply increasing the starting current or disabling protection is not an appropriate solution. The actual load, duty cycle and thermal requirements should be evaluated first.

8. What should be considered when selecting the ATS48C66Q for a heavy-duty application?

For heavy-duty applications, selection should be based primarily on the motor’s rated current and actual starting conditions rather than motor kW alone. The motor supply voltage, rated current, starting torque, acceleration time, load characteristics and number of starts per hour should all be considered.

The ATS48C66Q has different permissible motor power ratings depending on whether the motor is connected in-line or through the delta terminals and whether the application is classified as standard or severe duty. For example, the same starter can have significantly different applicable motor power ratings at 400 V depending on the connection and duty classification.

Heavy-duty applications can also produce substantially more thermal stress during starting. Long acceleration times and repeated starts can increase heat generation in both the motor and soft starter. The installation environment and temperature must therefore be considered during sizing.

The correct configuration should be established before commissioning, including the motor connection method, rated current settings, starting parameters, protection functions and control signals. Proper sizing and configuration allow the ATS48C66Q to provide stable starting performance while maintaining appropriate motor and starter protection.