Schneider Electric Altistart ATS48 is a soft start–soft stop unit for three-phase squirrel-cage asynchronous motors. The range covers 17–1200 A and uses torque-control technology to manage acceleration and deceleration, helping reduce starting-current peaks, pressure surges and mechanical stress.
The Schneider Electric Altistart 48 ATS48 Soft Starter is designed for controlled starting and stopping of three-phase asynchronous motors in standard and severe-duty industrial applications. Covering rated current options from 17 A to 1,200 A and operating voltages from 208 V to 690 V, the series supports motor applications up to 900 kW, depending on the selected model. Featuring Torque Control System (TCS) technology, adjustable current limiting, integrated motor and starter thermal protection, and Modbus communication, the ATS48 helps reduce mechanical stress during motor startup and shutdown. It is suitable for pumping, ventilation, compression and other industrial machinery requiring controlled motor operation.
The ATS48 uses torque control technology to regulate motor acceleration and deceleration, providing smoother starting and stopping performance than conventional direct-on-line starting. Its current-limiting function can be configured according to application requirements, with the referenced product configurations supporting current limitation up to 5 times the starter rating. This helps reduce starting current peaks and mechanical stress on motors, transmission components and driven equipment.
The ATS48 incorporates motor thermal protection and starter thermal protection to help protect equipment under abnormal operating conditions. Adjustable starting torque, acceleration time, current limitation and stopping parameters allow users to configure the starter for different load characteristics. Its controlled stopping functions are particularly useful in pumping applications where reducing abrupt pressure changes can help limit water hammer effects.
The Altistart 48 supports Modbus serial communication through an RS485 interface, enabling connection with compatible PLCs and industrial control systems. Its control and monitoring functions provide access to operating status, fault information and configurable parameters. Compatible remote display terminals and communication accessories are available for selected configurations.
The ATS48 is suitable for standard and severe-duty motor applications across industrial sectors, including centrifugal pumps, industrial fans, air compressors, conveyors, mixers, crushers, processing machinery, food and beverage production and chemical processing facilities.
Rated Operational Voltage: 208–690 V AC, depending on model.
Rated Operational Current: 17–1,200 A.
Motor Power: Up to 900 kW, depending on voltage and application duty.
Motor Compatibility: Three-phase squirrel-cage asynchronous motors.
Control Technology: Torque Control System (TCS).
Current Limitation: Configurable, with referenced models supporting up to 5 × starter rated current.
Operating Modes: Standard Duty and Severe Duty.
Protection: Motor thermal protection, starter thermal protection and phase-loss monitoring.
Communication: Modbus serial communication via RS485.
Applications: Pumps, fans, compressors, conveyors and heavy-duty industrial machinery.
| Item | Specification |
| Series | Altistart ATS48 (Q / Y) |
| Product Type | Soft start–soft stop unit for three-phase squirrel-cage asynchronous motors; six-thyristor control |
| Rated Current | 17–1200 A in the standard-duty model range; heavy-duty current ratings vary by model |
| Supply Voltage | Q series: 230–415 V three-phase; Y series: 208–690 V three-phase |
| Supply Frequency | 50/60 Hz ±5% automatic, or 50 Hz / 60 Hz ±20% when configured |
| Motor Power Range | Q series: 4–630 kW; Y series: 5.5–900 kW / 5–1200 HP |
| Duty Rating | AC-53a, according to IEC/EN 60947-4-2; standard-duty and heavy-duty options |
| Starting Control | TCS torque control; current limit adjustable by motor rated current, subject to the starter current limit |
| Stop Modes | Freewheel stop, controlled torque-ramp deceleration (0.5–60 s), and dynamic braking |
| Motor / Starter Protection | Calculated motor thermal protection, starter thermal protection, PTC sensor input, underload, overcurrent, phase-fault and extended-start detection |
| Additional Functions | Motor pre-heating, anti-reverse protection, two motor-parameter sets and operating status monitoring |
| Control I/O | 4 logic inputs, 2 logic outputs, 3 relay outputs and 1 analog output |
| Communication | Integrated RS485 Modbus via RJ45; up to 18 ATS48 units on the serial link; optional fieldbus modules available |
| Operating Temperature | −10 to +40°C without derating; derate 2% per °C above +40°C up to +60°C |
| Maximum Altitude | Up to 1,000 m without derating; derate 2.2% per 100 m above 1,000 m, up to 2,000 m |
| Protection Degree | IP20 for ATS48D17…C11 (IP00 without connections); IP00 for ATS48C14…M12 |
| Standards / Catalog Approvals | IEC/EN 60947-4-2; catalog lists UL, CSA, DNV, C-Tick, GOST, CCC, NOM 117, SEPRO and TCF |
The table below summarizes the standard- and heavy-duty current ratings and the indicative motor power at 400 V from the catalog. Q models cover 230–415 V; Y models cover 208–690 V.
| Model (Q / Y series) | Standard-Duty Current (A) | Heavy-Duty Current (A) | Motor Power at 400 V (Standard / Heavy Duty, kW) |
| ATS48D17Q / ATS48D17Y | 17 | 12 | 7.5 / 5.5 |
| ATS48D22Q / ATS48D22Y | 22 | 17 | 11 / 7.5 |
| ATS48D32Q / ATS48D32Y | 32 | 22 | 46341 |
| ATS48D38Q / ATS48D38Y | 38 | 32 | 18.5 / 15 |
| ATS48D47Q / ATS48D47Y | 47 | 38 | 22 / 18.5 |
| ATS48D62Q / ATS48D62Y | 62 | 47 | 30 / 22 |
| ATS48D75Q / ATS48D75Y | 75 | 62 | 37 / 30 |
| ATS48D88Q / ATS48D88Y | 88 | 75 | 45 / 37 |
| ATS48C11Q / ATS48C11Y | 110 | 88 | 55 / 45 |
| ATS48C14Q / ATS48C14Y | 140 | 110 | 75 / 55 |
| ATS48C17Q / ATS48C17Y | 170 | 140 | 90 / 75 |
| ATS48C21Q / ATS48C21Y | 210 | 170 | 110 / 90 |
| ATS48C25Q / ATS48C25Y | 250 | 210 | 132 / 110 |
| ATS48C32Q / ATS48C32Y | 320 | 250 | 160 / 132 |
| ATS48C41Q / ATS48C41Y | 410 | 320 | 220 / 160 |
| ATS48C48Q / ATS48C48Y | 480 | 410 | 250 / 220 |
| ATS48C59Q / ATS48C59Y | 590 | 480 | 315 / 250 |
| ATS48C66Q / ATS48C66Y | 660 | 590 | 355 / 315 |
| ATS48C79Q / ATS48C79Y | 790 | 660 | 400 / 355 |
| ATS48M10Q / ATS48M10Y | 1000 | 790 | 500 / 400 |
| ATS48M12Q / ATS48M12Y | 1200 | 1000 | 630 / 500 |
Selection note: power values are catalog ratings for 400 V line connection. Heavy-duty ratings are lower than standard-duty ratings. Final selection must match the motor nameplate current, supply voltage, starting time and load cycle. ATS48...Q models also support in-delta wiring, which uses different selection ratings.
Typical connection arrangements are combined into one figure for quick reference: line connection, external bypass connection and in-delta connection. In-delta wiring applies to ATS48...Q models only.
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