Technical Specifications

FAQ

1. What is the main function of the Schneider Electric ATS48C25Q soft starter?

The ATS48C25Q is a high-current Altistart 48 soft starter designed to control the starting and stopping of three-phase asynchronous motors. It uses torque control to gradually accelerate the motor instead of applying full line voltage immediately. This reduces starting current and helps minimize mechanical shock throughout the drive system. The ATS48C25Q is particularly suitable for large pumps, fans, compressors, conveyors, and heavy industrial machinery. It also incorporates motor thermal protection, starter thermal protection, and line phase-loss detection, providing additional protection during both starting and normal operation.

2. What motor power range can the ATS48C25Q handle?

The ATS48C25Q can be used across a broad motor power range, with the actual rating depending on supply voltage, motor connection, and whether the application is standard duty or severe duty. At 400 V with the starter connected in the motor supply line, it supports approximately 132 kW for standard applications and 110 kW for severe applications. When connected to the motor delta terminals, the applicable rating increases to approximately 220 kW for standard duty and 160 kW for severe duty. At 230 V, the corresponding ratings are 75 kW and 55 kW for line connection, and 132 kW and 110 kW for delta connection. Motor rated current and actual operating conditions should always be considered during selection.

3. What supply voltage does the ATS48C25Q support?

The ATS48C25Q is designed for three-phase AC supplies from 230 to 415 VAC, with a specified supply voltage tolerance of -15% to +10%. The normal supply frequency is 50–60 Hz, while the permitted network frequency range is approximately 47.5–63 Hz. Before commissioning, the actual incoming voltage should be checked and compared with the motor and starter requirements. The motor connection method must also be compatible with the selected supply voltage. Incorrect supply conditions, phase loss, or improper motor wiring can cause insufficient starting torque, excessive current, overheating, or protective trips.

4. How does torque control improve the starting performance of the ATS48C25Q?

The ATS48C25Q uses torque-controlled starting with current limited to approximately five times the motor rated current. Instead of allowing the motor to experience the high mechanical and electrical stress associated with direct-on-line starting, the soft starter manages the acceleration process more gradually. This can reduce stress on couplings, gearboxes, belts, pumps, shafts, and other mechanical components. It is particularly useful for high-inertia loads where a sudden application of torque can cause excessive mechanical shock. For pumping applications, controlled acceleration and deceleration can also help make hydraulic transitions smoother. The starting parameters should be adjusted according to the actual motor and load characteristics.

5. What should be checked if the motor does not accelerate correctly with the ATS48C25Q?

Begin by checking the three-phase input supply and confirming that all phases are present and within the specified voltage range. Then verify the motor rated-current setting, motor wiring, connection method, main power circuit, and control signals. If the motor is connected through its delta terminals, the complete connection arrangement should be checked carefully. If the electrical system is correct, inspect the mechanical load for blocked pumps, excessive friction, seized bearings, conveyor obstruction, or excessive inertia. The current limitation should also be reviewed. If the current limit is too low, the motor may not develop enough torque to accelerate the load. An unusually long acceleration time can be an indication of either insufficient starting torque or a mechanical problem.

6. Why can the ATS48C25Q trip during motor starting?

A starting trip may be caused by phase loss, abnormal supply voltage, excessive motor current, incorrect motor settings, excessive mechanical load, prolonged acceleration, or unsuitable current limitation. When a trip occurs, the fault information should be checked first to identify the actual operating condition. The motor nameplate current should be compared with the configured value, and the three-phase supply and motor connections should be inspected. For high-inertia equipment, the required acceleration time should also be evaluated because prolonged starting can create significant thermal stress. Mechanical problems such as blocked pumps, damaged bearings, or jammed transmission components can also cause excessive current. Repeatedly resetting the starter without correcting the underlying problem should be avoided.

7. How should the ATS48C25Q motor thermal protection be configured?

The motor rated-current parameter should be configured according to the actual motor nameplate value and the selected motor connection. This setting is important for the ATS48C25Q’s integrated motor thermal protection. If the configured current is too high, the motor may not receive adequate protection during an overload. If it is too low, the system may trip unnecessarily during normal operation or startup. The motor’s duty cycle, ambient temperature, cooling conditions, load level, acceleration time, and starting frequency should also be considered. For severe-duty applications, thermal accumulation over the complete operating cycle is especially important. Proper configuration should protect the motor without interfering with normal starting and operating conditions.

8. What should be checked before installing or replacing an ATS48C25Q?

Before installing or replacing an ATS48C25Q, verify the motor rated voltage, rated current, power, frequency, connection method, and mechanical load characteristics. Confirm whether the application is standard duty or severe duty and select the appropriate motor rating accordingly. The incoming three-phase supply, main power wiring, control circuit, grounding, protective devices, and motor insulation should be checked before energization. The starter should be mounted vertically and provided with sufficient ventilation for its forced-convection cooling system. After wiring, verify the motor current setting, starting parameters, current limitation, control inputs, protection functions, and communication configuration if Modbus is used. During commissioning, perform controlled start tests and monitor motor current, acceleration time, fault conditions, and temperature. For large, high-inertia, or frequently started motors, the complete duty cycle should be evaluated to prevent excessive thermal loading and ensure reliable long-term operation.