Product Overview

The Schneider ATS22C21S6 is an industrial Altistart 22 soft starter designed for controlled starting and stopping of three-phase asynchronous motors. It is intended for motor-driven equipment where direct-on-line starting may create excessive starting current, mechanical shock, or unnecessary stress on electrical and mechanical components.

Large industrial motors can place significant demands on an electrical installation when they are started directly across the line. The motor may draw a high starting current while simultaneously producing a rapid increase in torque. For pumps, fans, conveyors, compressors, and other machinery, this sudden transition can affect both the electrical supply and the connected mechanical equipment.

The ATS22C21S6 provides a controlled starting method that allows the motor to accelerate progressively. By controlling the motor starting process, the soft starter can help reduce the sudden mechanical and electrical effects associated with conventional direct starting.

The ATS22C21S6 is part of the Schneider Altistart 22 family and is designed for three-phase motor applications. Its 230 V AC control circuit is an important characteristic of the S6 version and should be checked carefully when selecting a replacement or integrating the unit into an existing control system.

The starter has an IcL rating of 210 A for standard motor-line connection applications. Depending on supply voltage and motor characteristics, it can be applied to relatively large industrial motors. The exact motor selection must always be based on motor full-load current, starting duty, load characteristics, and operating conditions rather than horsepower alone.

The supplied physical dimensions of the Schneider ATS22C21S6 are approximately 425 × 206 × 299 mm, while the supplied product weight is approximately 33 kg. These dimensions should be considered when planning cabinet installation, mounting, ventilation, cable routing, and maintenance access.

Technical Specifications

What Is the Schneider ATS22C21S6?

The Schneider ATS22C21S6 is an industrial motor soft starter used to control the starting and stopping of compatible three-phase asynchronous motors.

Its main purpose is to replace an abrupt direct-on-line starting process with a controlled acceleration sequence. When a motor is connected directly to the supply, the initial current can be several times greater than the motor’s normal operating current. The resulting torque can also be applied very quickly to the mechanical load.

For large motors, this behavior may cause voltage disturbances, mechanical shock, belt stress, gearbox loading, coupling stress, or excessive vibration. A soft starter provides a more gradual transition from the stopped condition to normal operation.

The ATS22C21S6 is therefore particularly useful in applications where the motor does not need continuous variable-speed operation but does require a controlled starting process.

It should be distinguished from a variable frequency drive. A VFD continuously changes frequency and voltage to control motor speed, while the ATS22C21S6 is primarily designed for controlled starting and stopping.

Function and Working Principle

The basic electrical arrangement can be represented as:

Three-Phase Supply → Circuit Protection → ATS22C21S6 → Three-Phase Motor → Mechanical Load

When the start command is received, the ATS22C21S6 begins its configured starting sequence. Instead of applying the motor’s full operating condition immediately, the starter controls the electrical power delivered during acceleration.

The Altistart 22 uses torque-controlled starting with current limitation. This allows the starting process to be adjusted according to the motor and mechanical load.

As the motor accelerates, the starter gradually moves the motor toward its normal operating condition. Once the motor reaches the required running state, the internal bypass function can provide a direct operating path for the motor, reducing losses associated with the power-control stage during normal operation.

The unit can also provide controlled stopping. This can be useful when an application benefits from a more gradual reduction in motor operation instead of an immediate stop.

The ATS22C21S6 also supports communication through Modbus over RS485. This allows the soft starter to be integrated into suitable industrial automation architectures for monitoring, configuration, and control.

Motor Power and Application Range

The ATS22C21S6 can be applied to different motor power levels depending on the supply voltage. Schneider’s Altistart 22 selection approach emphasizes selecting the soft starter according to the motor’s rated current, while horsepower and kilowatt values provide application references.

These values should be treated as application references rather than a substitute for motor-current selection. Actual suitability depends on motor nameplate current, starting conditions, duty cycle, ambient temperature, installation altitude, load inertia, and other system factors.

Role in Industrial Control Systems

The ATS22C21S6 can serve as the motor-starting component in an industrial automation system. It can be operated locally through the control circuit or integrated into a larger PLC-based control architecture.

A typical system may contain:

• PLC controller
• HMI operator interface
• ATS22C21S6 soft starter
• Three-phase asynchronous motor
• Incoming circuit breaker
• Motor protection equipment
• Isolation or switching contactor
• Emergency stop circuit
• Process sensors
• Modbus RS485 communication network

The PLC can determine when a motor should start based on process conditions, while the ATS22C21S6 handles the motor acceleration profile.

For example, in a pump application, a PLC may receive a low-pressure signal from a process sensor. The PLC can then issue a start command to the soft starter. The ATS22C21S6 controls the motor acceleration, while the PLC continues to monitor pressure, motor status, and fault conditions.

Industrial Applications

Pump Systems

Pumping equipment is one of the most common applications for soft starters. Controlled starting can help reduce sudden mechanical and hydraulic effects during motor acceleration.

In larger pumping systems, controlled stopping may also be useful for reducing abrupt changes in flow or pressure, depending on the hydraulic design.

Fans and Blowers

Industrial fans may have high rotational inertia. Direct starting can place a sudden demand on the motor and mechanical system. The ATS22C21S6 can provide a controlled acceleration sequence suitable for appropriately sized fan applications.

Conveyors

Heavy conveyors can experience significant mechanical stress when started suddenly. A soft starter can allow the motor to accelerate more progressively, reducing sudden torque transfer through belts, shafts, gearboxes, and couplings.

Compressors

Large compressor motors may require substantial starting current. The ATS22C21S6 can be considered when controlled motor starting is needed and continuous variable-speed control is not a primary requirement.

Mixers and Agitators

Industrial mixers can have high starting resistance depending on the process material. A controlled motor-starting sequence can help prevent an abrupt application of torque to the mechanical system.

Material Handling

Industrial material-handling machinery often uses large motors connected to belts, rollers, gearboxes, or other transmission equipment. Soft starting can improve the transition from stopped to running conditions.

HVAC Equipment

Large ventilation and air-handling systems can use soft starters for fan motors when controlled acceleration is required without the need for continuous speed adjustment.

Installation and System Integration

Correct installation is essential for reliable operation. The ATS22C21S6 should be selected and installed according to the motor’s electrical characteristics, application duty, control architecture, and cabinet environment.

Verify Motor Data

Before installation, record the motor nameplate voltage, current, frequency, power, connection arrangement, and operating duty. Motor current is especially important when selecting and configuring the soft starter.

Verify the Power Supply

The ATS22C21S6 is designed for a three-phase supply in the 230…600 V range. The actual installation voltage must be verified before energization.

Check the Control Voltage

The S6 version uses a 230 V AC control circuit. This is an important difference when compared with ATS22 variants carrying other suffixes. The control-voltage requirement must be confirmed before wiring the control circuit.

Install Appropriate Protection

Suitable upstream short-circuit protection, isolation, and motor protection should be included in the complete motor-control system. Protection selection should take into account the motor, soft starter, electrical installation, and applicable standards.

Mechanical Installation

The ATS22C21S6 has supplied dimensions of approximately 425 × 206 × 299 mm and a supplied weight of approximately 33 kg.

The mounting structure must therefore be capable of supporting the equipment securely. Adequate clearance should also be provided for cable installation, inspection, airflow, and maintenance.

Thermal Management

The unit uses forced convection for cooling. Cabinet design should provide suitable airflow and prevent excessive heat accumulation around the soft starter.

Control Connections

Start, stop, fault, and status circuits should be wired according to the control architecture. If a PLC is used, safety interlocks and permissive conditions should be incorporated into the control sequence.

Motor Wiring

All motor power connections should be inspected carefully before energization. Phase sequence, motor connection, terminal tightness, cable sizing, and protective grounding should be checked during commissioning.

Parameter Configuration

The motor current and starting characteristics should be configured according to the actual motor and load. Different machines may require different acceleration and stopping profiles.

Commissioning

Initial commissioning should include verification of control signals, motor rotation direction, acceleration time, current behavior, stopping characteristics, alarms, and communication status.

The equipment should be tested under controlled conditions before the machine is returned to full production.

Compatible System Components

Recommended Alternative Models

When selecting an alternative to the ATS22C21S6, engineers should compare the complete part number rather than relying only on the product family or physical dimensions.

The control voltage is particularly important. The S6 version uses 230 V control, while the S6U version uses 110 V control. These models should therefore not be treated as electrically identical replacements.

Key Advantages

• Designed for three-phase asynchronous motor control
• Part of the Schneider Altistart 22 soft starter family
• Provides controlled motor acceleration
• Supports controlled stopping for suitable applications
• 210 A starter rating for standard motor-line connection applications
• 230 V AC control circuit
• Supports 230…600 V AC motor supply applications
• Torque-controlled starting
• Starting current limitation of approximately 3.5 × In
• Internal bypass function
• Modbus communication through RS485
• Three logic inputs and two relay outputs
• PTC motor protection input
• Suitable for pumps, fans, conveyors, compressors, and industrial machinery
• Forced-convection cooling
• Supplied dimensions of approximately 425 × 206 × 299 mm
• Supplied weight of approximately 33 kg

Technical FAQs

What is the Schneider ATS22C21S6?

The Schneider ATS22C21S6 is an Altistart 22 industrial soft starter designed for controlled starting and stopping of three-phase asynchronous motors.

What is the control voltage of the ATS22C21S6?

The ATS22C21S6 uses a 230 V AC control circuit. This should be verified before connecting the control power.

What is the starter current rating?

The ATS22C21S6 has an IcL starter rating of approximately 210 A for standard motor-line connection applications.

What is the rated motor supply voltage?

The model is designed for three-phase motor supply applications in the approximate 230…600 V AC range, subject to the applicable installation conditions.

What motor applications are suitable for the ATS22C21S6?

Typical applications include pumps, fans, conveyors, compressors, mixers, material-handling systems, and other industrial motor-driven machinery.

Does the ATS22C21S6 have an internal bypass?

Yes. The ATS22C21S6 includes an internal bypass function that can allow the motor to transition into normal running conditions after the starting process.

Does the ATS22C21S6 support Modbus?

Yes. The model supports Modbus communication through an RS485 multidrop interface, allowing it to be integrated into suitable industrial control and monitoring systems.

Can the ATS22C21S6 be controlled by a PLC?

Yes. A PLC can be integrated with the soft starter to provide automatic start, stop, status, alarm, and process-control functions.

What is the difference between ATS22C21S6 and ATS22C21S6U?

The most important difference is the control voltage. The ATS22C21S6 uses 230 V AC control, while the ATS22C21S6U uses 110 V AC control. The complete model number must therefore be checked when selecting a replacement.

Is the ATS22C21S6 a variable frequency drive?

No. It is a soft starter. It is primarily designed to control motor starting and stopping rather than provide continuous variable-frequency speed control.

What are the dimensions of the ATS22C21S6?

The supplied dimensions are approximately 425 × 206 × 299 mm.

How much does the ATS22C21S6 weigh?

The supplied product weight is approximately 33 kg.

What should be checked before replacing an ATS22C21S6?

The motor rated current, supply voltage, control voltage, starting duty, load characteristics, cabinet dimensions, cooling requirements, control wiring, and communication requirements should all be checked before selecting a replacement.

Conclusion

The Schneider ATS22C21S6 Soft Starter is a high-capacity industrial motor-control device designed to provide controlled starting and stopping for three-phase asynchronous motors. Its 210 A starter rating, 230 V control circuit, internal bypass, torque-controlled starting, and Modbus RS485 communication make it suitable for a wide range of industrial motor-control applications.

The model is particularly useful where a motor requires smoother acceleration but continuous variable-speed control is not necessary. Pumps, fans, conveyors, compressors, mixers, and material-handling equipment can all benefit from a properly configured soft-starting solution.

The supplied dimensions of approximately 425 × 206 × 299 mm and weight of approximately 33 kg should be incorporated into the electrical cabinet and mechanical installation design. Adequate support, ventilation, wiring space, and maintenance clearance are important considerations for reliable operation.

For system integrators, electrical engineers, OEM machine builders, and maintenance technicians, correct model selection is essential. In particular, the 230 V control voltage of the ATS22C21S6 must be distinguished from other ATS22 variants such as the S6U version. Motor current, supply voltage, load characteristics, starting duty, protection, and control architecture should all be evaluated before installation.

When correctly matched to the motor and application, the Schneider ATS22C21S6 provides a practical and reliable method for improving motor-starting behavior while integrating naturally into modern industrial automation and motor-control systems.