Product Overview

The Schneider Electric ATS48C79Y Altistart 48 Soft Starter is a high-capacity motor starting and stopping controller designed for three-phase asynchronous motors used in industrial applications. As part of Schneider Electric’s Altistart 48 series, it provides controlled motor acceleration and deceleration to help reduce electrical and mechanical stress during motor operation.

Large industrial motors can draw substantial starting current when connected directly to the power supply. This can create voltage disturbances, mechanical shock, and additional stress on motors, couplings, pumps, compressors, and other driven equipment. A soft starter addresses these challenges by controlling the voltage applied to the motor during starting and stopping.

The ATS48C79Y is designed for demanding industrial environments, including heavy-duty machinery and pumping systems. Its supported supply voltage range is 208–690 V AC, and its product documentation identifies a factory current setting of 720 A. The device also provides configurable motor protection and torque-controlled starting and stopping functions.

Unlike a variable frequency drive, a conventional soft starter is primarily designed to manage motor acceleration and deceleration rather than provide continuous variable-speed operation. Once the motor reaches its operating condition, the application may use an external bypass arrangement to reduce heat dissipation in the starter.

The ATS48C79Y is a large-frame industrial soft starter with supplied dimensions of 890 × 770 × 315 mm and a weight of approximately 115 kg. Its physical size and electrical capacity make it suitable for installation in appropriately designed industrial electrical cabinets and motor-control rooms.

The ATS48C79Y has been discontinued, and Schneider Electric identifies the ATS480C79Y from the Altivar Soft Starter ATS480 range as its recommended replacement. Existing installations may continue to require the original model for maintenance, equipment restoration, and spare-parts replacement.

Technical Specifications

Important: The 720 A factory current setting should not be interpreted as a universal current rating for every application. Actual operating current and motor power selection depend on voltage, standard-duty or heavy-duty operation, and whether the starter is connected in the motor supply line or inside the motor delta.

Function and Working Principle

The ATS48C79Y controls the starting and stopping process of an asynchronous motor through electronic power switching. Its main objective is to manage motor torque and current during transient operating conditions.

1. Controlled Motor Starting

When a large motor starts directly across the line, it can draw several times its normal operating current. This high starting current may affect the electrical distribution system and create sudden mechanical movement.

The ATS48C79Y gradually controls the motor’s starting conditions. By regulating the voltage applied to the motor through its power electronics, it helps limit starting current and produce a more controlled acceleration process.

This function is particularly useful for large motors connected to pumps, compressors, conveyors, and other equipment where sudden acceleration can cause operational problems.

2. Torque Control

The Altistart 48 series uses torque-controlled starting and stopping technology. Instead of relying only on a simple voltage ramp, the controller manages motor torque during the starting process.

This can help reduce mechanical shock and improve the transition from standstill to normal operating speed.

For pump applications, controlled torque can also help reduce sudden pressure changes in the piping system. The actual result depends on pump characteristics, hydraulic conditions, and the selected control parameters.

3. Current Limitation

The ATS48C79Y includes current-limiting functionality. The starting current limit can be configured according to the motor and application requirements.

Current limitation is useful when the electrical supply has restrictions on starting current or when several large motors operate within the same distribution system.

The current limit must be selected carefully. An excessively low setting may prevent the motor from developing sufficient starting torque, while an unnecessarily high setting may reduce the benefits of soft starting.

4. Controlled Motor Stopping

In addition to soft starting, the ATS48C79Y supports controlled motor deceleration.

When a motor stops abruptly, the driven equipment may experience mechanical shock. This can be problematic in pumping systems, conveyor equipment, and industrial machinery with significant inertia.

A controlled stopping profile can help reduce sudden changes in mechanical torque. For applications requiring specialized braking or accurate positioning, a soft starter may not provide all the functions of a dedicated drive or braking system.

5. Motor Thermal Protection

Motor protection is an important function in industrial motor-control systems. The ATS48C79Y includes motor thermal protection features designed to help monitor operating conditions and protect the connected motor against certain overload situations.

Correct motor data and protection settings are essential. The starter must be configured according to the motor nameplate, application duty, operating environment, and applicable protection requirements.

6. External Bypass Configuration

An external bypass arrangement can be used with the Altistart 48 system. Once the motor has completed its starting process, the bypass contactor can provide a path for normal motor operation.

This arrangement reduces the time that current passes through the starter’s power electronics during steady-state operation and can help reduce heat dissipation.

The bypass contactor, wiring, interlocking, and protection must be selected and installed according to the manufacturer’s instructions.

Role in Industrial Motor Control Systems

The ATS48C79Y can serve as the motor-starting control component within a larger industrial automation and electrical distribution system.

It is commonly integrated with circuit breakers, contactors, PLC systems, motor protection devices, and operator interfaces.

PLC Integration

A programmable logic controller can coordinate the soft starter with the wider production process.

For example, a PLC may issue a motor-start command after confirming that safety interlocks, valve positions, pressure conditions, and other operating requirements are satisfied.

The ATS48C79Y provides control and status interfaces that can be incorporated into a suitable PLC architecture. Its configurable logic outputs and relay outputs can provide information about fault conditions, completion of starting, and motor-powered status.

The exact PLC wiring and control logic should be designed according to the installed control voltage and terminal configuration.

HMI and Operator Monitoring

An HMI can provide operators with access to motor operating conditions, alarm information, and process status.

Depending on the system design, the HMI may communicate with a PLC that coordinates the soft starter. Operators can use this arrangement to monitor motor operation and respond to abnormal conditions.

A suitable operator interface can also help maintenance personnel identify starting problems and review relevant operating information.

Motor Protection and Electrical Distribution

The ATS48C79Y operates as part of a coordinated motor-control circuit. It should be used with appropriately selected upstream protection and switching equipment.

The complete installation must account for motor current, short-circuit protection, overload protection, cable ratings, grounding, and electrical isolation requirements.

The soft starter does not replace all protective devices required in an industrial motor installation.

Industrial Applications

The ATS48C79Y is designed for large industrial asynchronous motors and applications where controlled starting and stopping are important.

1. Industrial Pumping Systems

Large pumps are commonly used in water treatment, industrial processing, power generation, and utility infrastructure.

Direct-on-line starting can create sudden pressure changes in piping systems. The ATS48C79Y can provide controlled motor acceleration and deceleration to help reduce hydraulic shock under suitable operating conditions.

Typical applications include:

• Industrial water supply pumps
• Water treatment pumping stations
• Process circulation pumps
• Cooling-water systems
• Industrial transfer pumps

The correct starting and stopping settings depend on pump type, system pressure, pipeline design, and motor characteristics.

2. Compressors

Industrial compressors often use large motors that require substantial starting torque and current.

The ATS48C79Y can help manage the starting process and reduce electrical disturbances associated with direct-on-line motor starting.

Before selecting the starter, engineers should consider compressor loading conditions, unloading arrangements, starting frequency, and the required motor torque.

3. Conveyor Systems

Large conveyor systems may transport raw materials, bulk products, or finished goods across industrial facilities.

Controlled starting can help reduce sudden mechanical stress on belts, couplings, gearboxes, and supporting structures.

The ATS48C79Y can be used in suitable fixed-speed conveyor applications where the primary requirement is controlled motor starting and stopping rather than continuous speed adjustment.

4. Industrial Fans and Blowers

Large ventilation fans and process blowers are used in manufacturing facilities, power plants, and industrial ventilation systems.

A soft starter can reduce the electrical and mechanical impact of motor starting. It may also help coordinate the motor-starting sequence in installations containing several large fans.

The starter should be selected according to motor current, fan inertia, operating duty, and the required starting torque.

5. Heavy Industrial Machinery

The Altistart 48 series is designed for demanding motor-control applications. The ATS48C79Y may be used in appropriate industrial machinery where a large asynchronous motor requires controlled acceleration and deceleration.

Typical application environments include:

• Mining and material handling
• Industrial processing plants
• Manufacturing facilities
• Utility infrastructure
• Large mechanical equipment

The motor’s actual electrical characteristics and load profile must always be checked before selecting the starter.

Installation and System Integration

Because the ATS48C79Y is a large-capacity soft starter, installation requires careful electrical and mechanical planning.

1. Verify Supply Voltage

The ATS48C79Y supports a supply voltage range of 208–690 V AC.

Before installation, verify the actual supply voltage, frequency, motor voltage, motor current, and electrical distribution arrangement.

The starter must be selected according to the motor’s rated current and the applicable standard-duty or heavy-duty requirements.

2. Confirm Motor Compatibility

Check the motor nameplate for:

• Rated voltage
• Rated current
• Rated power
• Rated frequency
• Power factor
• Motor connection
• Starting requirements

The soft starter must be compatible with the motor and the selected connection method.

Incorrect current settings can result in starting difficulties, unwanted trips, or insufficient motor protection.

3. Mechanical Mounting

The supplied dimensions are 890 × 770 × 315 mm, and the supplied weight is 115 kg.

These figures should be used when planning the initial cabinet layout and handling arrangements. Confirm the manufacturer’s mounting drawing and required clearances before installation.

The ATS48C79Y has an IP00 protection rating. It is an open device and must be installed inside a suitable electrical enclosure or controlled-access electrical area.

The installation should provide:

• Adequate ventilation
• Sufficient space for cooling airflow
• Appropriate mounting support
• Protection against dust and moisture
• Safe access for inspection and maintenance
• Suitable cable-entry and termination arrangements

Because of its weight, suitable lifting and handling equipment may be required during installation.

4. Electrical Wiring

The incoming supply, motor connections, control wiring, and grounding must follow the manufacturer’s installation instructions.

Power conductors should be correctly sized for the operating current and installation conditions.

Control wiring should be routed appropriately to reduce interference from high-current power conductors.

All connections must be tightened to the specified torque. Electrical isolation and lockout procedures must be followed before installation or maintenance.

5. Configure Starting Parameters

The starter must be configured according to the motor and load characteristics.

Important parameters may include:

• Motor rated current
• Current limitation
• Starting torque
• Acceleration time
• Deceleration time
• Motor thermal protection
• Relay output assignments
• Logic output functions

The configuration should be tested under actual operating conditions to confirm that the motor accelerates reliably without exceeding electrical or mechanical limits.

6. PLC and Control Circuit Integration

When connected to a PLC, the ATS48C79Y can form part of an automated motor-control sequence.

Typical control signals include motor start commands, fault indications, end-of-starting status, and motor-powered status.

The control circuit voltage is 110–230 V AC. Engineers should verify the control supply and interface requirements before connecting external devices.

7. Commissioning and Functional Testing

Before the equipment is returned to normal operation, perform the required electrical and functional checks.

Verify the following:

• Supply voltage and phase sequence
• Motor connection and grounding
• Control circuit wiring
• Current settings
• Starting and stopping performance
• Motor protection settings
• PLC command response
• Fault and status indications
• Cooling and ventilation conditions

Record the final configuration for future maintenance and troubleshooting.

Compatible System Components

The ATS48C79Y is typically installed as part of a complete industrial motor-control system.

The exact system configuration depends on the motor, application, electrical design, and required protection functions. These components are not necessarily included with the ATS48C79Y.

Alternative Models and Replacement Considerations

The ATS48C79Y belongs to the discontinued Altistart 48 product family. Schneider Electric identifies the ATS480C79Y as its recommended replacement.

The models listed above are not automatically interchangeable.

When selecting a replacement, engineers should compare:

• Supply voltage range
• Rated operational current
• Standard-duty and heavy-duty ratings
• Motor power at the actual operating voltage
• Starting-current limitation
• Control circuit voltage
• Starting and stopping functions
• Protection features
• Relay and logic output configuration
• Communication requirements
• Mounting dimensions
• Cooling and ventilation requirements
• PLC and HMI integration

Although ATS480C79Y is the recommended successor, replacing an ATS48C79Y may require wiring changes, parameter adjustments, cabinet modifications, and recommissioning.

A replacement decision should be based on the complete motor-control application rather than the product name or current rating alone.

Key Advantages

Controlled Motor Acceleration

The ATS48C79Y manages motor starting conditions to help reduce high starting-current effects and sudden mechanical movement.

Torque-Controlled Starting

Its torque-control functionality supports controlled motor acceleration and can help reduce mechanical shock in suitable applications.

Controlled Stopping

The starter supports controlled motor deceleration, which can be useful for pumps and machinery requiring a smoother stopping sequence.

Integrated Motor Protection

Built-in motor thermal protection helps monitor operating conditions and supports motor protection when correctly configured.

Configurable Control Outputs

The starter provides configurable logic outputs and relay status signals for integration with industrial control systems.

Support for Large Industrial Motors

Its high-capacity design supports demanding applications involving large asynchronous motors, subject to the specified electrical and duty ratings.

External Bypass Capability

An external bypass arrangement can reduce power-electronic heat dissipation during normal motor operation when correctly designed and installed.

Technical FAQs

1. What is the Schneider Electric ATS48C79Y?

The ATS48C79Y is an Altistart 48 soft starter designed to control the starting and stopping of three-phase asynchronous motors in industrial applications.

2. What voltage does the ATS48C79Y support?

It supports a supply voltage range of 208–690 V AC. The actual supply and motor configuration must be checked before installation.

3. What is the factory current setting?

The product documentation identifies a factory current setting of 720 A. The applicable operating current rating depends on duty classification and connection configuration.

4. What is the control circuit voltage?

The documented control circuit voltage is 110–230 V AC at 50/60 Hz.

5. What is the difference between a soft starter and a variable frequency drive?

A soft starter primarily controls motor acceleration and deceleration. A variable frequency drive can continuously adjust motor speed by changing the output frequency.

The ATS48C79Y is designed for controlled motor starting and stopping rather than continuous variable-speed operation.

6. Can the ATS48C79Y be used with large industrial pumps?

Yes. The Altistart 48 series is designed for demanding industrial applications, including pumping systems. The motor current, starting requirements, pump characteristics, and operating duty must be evaluated before selection.

7. Does the ATS48C79Y support PLC integration?

Yes. Its control and status interfaces can be incorporated into a PLC-based motor-control system. The wiring and signal assignments must match the selected control architecture.

8. What is the protection rating?

The ATS48C79Y has an IP00 protection rating. It must be installed in an appropriate electrical enclosure or controlled-access area.

9. Is the ATS48C79Y discontinued?

Yes. Schneider Electric has discontinued the ATS48C79Y. The ATS480C79Y is identified as its recommended replacement.

10. Can ATS480C79Y replace ATS48C79Y directly?

It is the recommended successor, but a direct physical and electrical substitution should not be assumed. Check ratings, wiring, control interfaces, dimensions, mounting, and parameter requirements before replacement.

11. What should be checked when purchasing a used ATS48C79Y?

Check the complete model number, nameplate, physical condition, terminal condition, signs of overheating, and available functional-test information. For a high-capacity soft starter, the condition of power connections and cooling components is particularly important.

12. What are the dimensions and weight of the ATS48C79Y?

The supplied dimensions are 890 × 770 × 315 mm, and the weight is 115 kg. These values are consistent with the published Altistart 48 dimensional data.

Procurement and Maintenance Recommendations

The ATS48C79Y is a discontinued high-capacity industrial soft starter. Procurement should therefore begin with accurate model identification and confirmation of the required electrical configuration.

Before purchasing, verify the complete catalog number and compare the product nameplate with the specifications of the installed unit. Confirm the supply voltage, motor current, duty requirements, control circuit voltage, and available protection functions.

For used or surplus equipment, request clear photographs of the front panel, nameplate, terminals, and power connections. Check whether the unit has been tested and whether any accessories or documentation are included.

Because the unit weighs approximately 115 kg, transportation and installation planning should include appropriate lifting equipment and secure packaging. Verify the actual shipping dimensions and gross weight separately from the product specifications.

During maintenance, inspect power terminals, control wiring, cooling passages, cabinet ventilation, and the condition of associated contactors. Review fault records and verify motor protection settings according to the maintenance schedule.

For replacement projects, evaluate the ATS480C79Y and confirm whether the existing motor-control cabinet, PLC logic, wiring, and protection devices can be retained. A replacement may require electrical modifications and recommissioning.

Conclusion

The Schneider Electric ATS48C79Y Altistart 48 Soft Starter is a high-capacity motor starting and stopping controller designed for three-phase asynchronous motors operating in industrial environments. It supports 208–690 V AC supply systems and provides torque-controlled starting, current limitation, motor thermal protection, and configurable control outputs.

With supplied dimensions of 890 × 770 × 315 mm and a weight of approximately 115 kg, the ATS48C79Y is intended for large industrial motor-control installations. Although the model has been discontinued, it remains relevant to maintenance and spare-parts requirements in existing Altistart 48 systems.

For replacement planning, Schneider Electric recommends the ATS480C79Y. Careful comparison of motor ratings, electrical interfaces, installation dimensions, and control requirements is essential to ensure a suitable replacement.