Product Overview

The ABB PST175-600-70 1SFA894011R7000 Soft Starter is an advanced motor-starting and stopping device designed for controlling three-phase AC motors in industrial applications. As part of ABB’s PST softstarter family, it provides controlled motor acceleration and deceleration to help reduce electrical disturbances and mechanical stress during motor operation.

Direct-on-line motor starting can produce high inrush currents and sudden mechanical torque. These effects may place additional stress on electrical distribution systems, motors, gearboxes, couplings, belts, and driven machinery. A soft starter addresses these challenges by gradually increasing the voltage supplied to the motor during startup.

The PST175-600-70 supports a main-circuit operating voltage range of 208–600 V AC and has a rated operational current of 175 A for in-line connection. At 400 V, its rated motor power is 90 kW for in-line connection. It can also support an inside-delta installation with a rated current of 300 A and a motor power rating of 160 kW at 400 V, provided the motor and installation meet the manufacturer’s requirements.

The unit uses an auxiliary control supply of 100–250 V AC at 50/60 Hz and supports 24 V DC control-circuit operation. Its adjustable starting and stopping parameters allow engineers to adapt motor behavior to different load conditions.

The PST175-600-70 is suitable for industrial equipment where controlled motor starting, reduced starting stress, and coordinated stopping are important. Typical applications include pumps, fans, compressors, conveyors, and other motor-driven machinery.

Technical Specifications

Note: Electrical ratings depend on connection method and operating conditions. Always refer to the manufacturer’s installation documentation when selecting the operating mode and configuring the motor.

Operating Principle and Control Functions

The ABB PST175-600-70 controls the voltage applied to a three-phase motor during starting and stopping. Instead of immediately applying full supply voltage, it gradually changes the motor’s electrical input according to configured parameters.

1. Controlled Motor Starting

When a motor starts directly across the line, it can draw several times its normal operating current. This sudden demand may cause voltage drops and additional stress on electrical equipment.

The PST175-600-70 gradually increases the motor voltage during startup. Engineers can adjust the initial voltage and ramp time to achieve a suitable starting response for the connected load.

This is particularly useful for equipment that needs controlled acceleration or operates on electrical networks where starting-current disturbances must be managed.

2. Adjustable Starting Parameters

The soft starter provides adjustable starting parameters that allow the commissioning engineer to match motor acceleration to the application.

Relevant settings include:

• Initial starting voltage.
• Starting ramp time.
• Motor rated current.
• Current limit.
• Starting characteristics for different load conditions.

These parameters should be configured according to the motor nameplate, mechanical load, and required starting time.

3. Controlled Motor Stopping

The PST175-600-70 also supports controlled stopping. Rather than immediately disconnecting the motor from the supply, the soft starter can gradually reduce the applied voltage according to the selected stopping parameters.

This function is useful for applications where sudden stopping may cause pressure fluctuations, mechanical shocks, or unwanted movement.

For example, controlled stopping can be beneficial in pump systems where abrupt motor shutdown may contribute to water hammer.

4. Electronic Motor Overload Protection

The PST series includes electronic overload protection. This function monitors motor operating conditions and helps protect the motor against excessive thermal loading.

The motor’s rated current must be entered correctly during commissioning. Incorrect settings can reduce protection effectiveness or cause unnecessary trips.

The soft starter’s protection functions should be coordinated with upstream circuit protection and the complete motor-control design.

5. Current Limiting

The current-limit function allows engineers to restrict the current drawn during motor startup.

For the PST175-600-70, the documented adjustment range is 1.5–7 times the rated current. The selected limit must provide sufficient starting torque while keeping the starting current within the permitted range.

A current limit that is too low may prevent the motor from accelerating properly, particularly when starting under a heavy load.

6. In-Line and Inside-Delta Operation

The PST175-600-70 supports two installation arrangements: in-line connection and inside-delta connection.

In-line operation places the soft starter directly in the motor supply circuit. Its rated operational current is 175 A.

Inside-delta operation uses a different connection arrangement involving the motor winding connections. The published rating for this configuration is 300 A.

These arrangements are not interchangeable without checking the motor winding connections, supply arrangement, terminal configuration, and ABB installation instructions.

Role in Industrial Automation Systems

The PST175-600-70 can operate as part of a larger industrial motor-control system. It manages motor starting and stopping while coordinating with protective devices, contactors, PLCs, and operator interfaces.

PLC Integration

A PLC can coordinate the soft starter with other equipment in an automated process.

Typical control functions include:

• Issuing motor start and stop commands.
• Monitoring operating status.
• Receiving fault or trip information.
• Coordinating motor operation with process sequences.
• Managing equipment interlocks.

The actual PLC interface depends on the control wiring and any communication accessories installed in the system.

Electrical Protection Coordination

A soft starter is normally installed together with suitable upstream protective equipment. Circuit breakers, fuses, contactors, and overload protection must be selected according to the motor and installation requirements.

The complete protection arrangement should account for short-circuit protection, motor overload, isolation, and safe maintenance procedures.

HMI and Operator Monitoring

An HMI can provide operators with information about motor operation and equipment status. Depending on the system design, the HMI may communicate with the PLC, which coordinates the soft starter.

This arrangement allows operators to monitor motor operation without needing to interact directly with the power-control equipment.

Process Equipment Coordination

The soft starter can be integrated into automated systems involving pumps, fans, compressors, and conveyors. Its controlled starting and stopping functions help coordinate motor operation with the surrounding process.

The final control strategy should consider the motor’s electrical characteristics, load behavior, and required operating sequence.

Industrial Applications

The ABB PST175-600-70 is designed for medium- and higher-power industrial motor applications. Its 175 A in-line rating and 300 A inside-delta rating make it suitable for appropriately sized three-phase motors.

1. Industrial Pumping Systems

Pumps are widely used in water treatment, chemical processing, cooling systems, and industrial fluid transportation.

A soft starter can gradually accelerate a pump motor, reducing sudden electrical demand and mechanical stress during startup.

Controlled stopping may also help reduce abrupt pressure changes in suitable pumping applications.

2. Industrial Fans and Ventilation Systems

Large fans and ventilation equipment often use high-power motors. Direct starting can create significant electrical and mechanical disturbances.

The PST175-600-70 can provide controlled acceleration for compatible fan motors, helping reduce starting stress on belts, shafts, bearings, and other mechanical components.

3. Air Compressors

Industrial compressors frequently operate under changing load conditions. Motor starting requirements can vary according to pressure, unloading arrangements, and mechanical configuration.

A soft starter can help control the motor’s acceleration. The compressor’s unloading system and starting sequence must be coordinated with the soft starter to ensure reliable operation.

4. Conveyor Systems

Conveyors used in manufacturing, mining, and material handling may require controlled motor starting to reduce sudden mechanical forces.

The PST175-600-70 can be used in suitable conveyor installations where a soft-starting method meets the required torque and acceleration characteristics.

5. Industrial Processing Machinery

Mixers, processing equipment, and other motor-driven machines may experience significant mechanical resistance during startup.

Adjustable starting parameters allow engineers to adapt motor acceleration to the characteristics of the driven equipment. The selected settings must provide sufficient starting torque for the application.

6. Water and Wastewater Treatment

Pumping and ventilation equipment are common in water and wastewater facilities. Soft starters can support controlled motor operation in these systems.

The PST175-600-70 may be used where its electrical ratings and starting characteristics match the installed motors and process requirements.

Installation and System Integration

Correct installation is essential for the safe operation and performance of the ABB PST175-600-70.

1. Verify the Main Supply

Before installation, confirm that the incoming three-phase supply is within the unit’s rated main-circuit voltage range of 208–600 V AC.

The motor voltage, rated current, power, frequency, and connection arrangement must also be checked.

The selected operating configuration must comply with the soft starter’s current and power ratings.

2. Check the Control Supply

The PST175-600-70 uses a control supply of 100–250 V AC at 50/60 Hz and supports 24 V DC control-circuit operation.

Control wiring should be checked against the terminal diagram before energizing the equipment. Do not assume that all control terminals use the same voltage reference.

3. Mounting and Panel Design

The supplied dimensions are 420 × 270 × 360 mm, and the listed weight is 21.5 kg.

The control cabinet must provide sufficient space for mounting, cable connections, maintenance access, and heat dissipation.

Allow the ventilation clearances required by ABB. The soft starter should not be installed in an enclosure where excessive temperature, conductive dust, moisture, or corrosive substances can affect its operation.

4. Main Circuit Wiring

The main power connections must be made according to the manufacturer’s wiring instructions.

For in-line installation, the soft starter is connected directly in the motor supply circuit. For inside-delta installation, the motor winding connections and soft starter terminals must be arranged according to the approved diagram.

Incorrect wiring can damage equipment or create unsafe operating conditions.

5. Configure Motor Parameters

During commissioning, enter the motor’s rated current and configure the starting and stopping parameters.

Important settings include:

• Motor rated current.
• Initial starting voltage.
• Starting ramp time.
• Stopping ramp time.
• Current limit.
• Applicable overload protection settings.

The parameters should be adjusted through controlled testing under the actual load conditions.

6. Verify Protection and Interlocks

Check the coordination between the soft starter, upstream protective devices, contactors, emergency-stop circuits, and PLC interlocks.

Confirm that fault conditions result in the intended machine response. Safety-related functions must be implemented using appropriately designed safety circuits rather than relying solely on ordinary motor-control commands.

7. Commissioning Test

After completing installation, inspect all power and control connections. Verify the motor’s rotation direction, starting behavior, acceleration time, stopping behavior, and protection response.

Record the final parameter settings for future maintenance and replacement.

Compatible System Components

The PST175-600-70 can be integrated with various industrial electrical and automation components.

The exact components required depend on the motor, application, electrical installation, and applicable safety standards.

Alternative Models and Replacement Considerations

When replacing the PST175-600-70, engineers should compare electrical ratings and installation requirements rather than relying only on the product series.

Before selecting a replacement, check:

• Main-circuit voltage.
• Rated operational current.
• Motor power and duty requirements.
• In-line or inside-delta connection.
• Control supply voltage.
• Control-circuit voltage.
• Starting and stopping requirements.
• Current-limit range.
• Overload protection settings.
• Mounting dimensions and wiring arrangements.
• PLC and HMI integration requirements.

A higher-current soft starter is not automatically a direct replacement. Differences in terminal layout, control functions, dimensions, and parameter settings may require modifications to the installation.

Key Advantages

Controlled Motor Starting

The soft starter gradually increases motor voltage, helping reduce the electrical and mechanical impact associated with direct-on-line starting.

Adjustable Starting Parameters

Engineers can configure initial voltage, ramp time, and current limit to suit different motor and load conditions.

Controlled Stopping

Adjustable stopping characteristics can help reduce abrupt mechanical movement in applications where controlled deceleration is beneficial.

Integrated Electronic Overload Protection

The integrated electronic overload function supports motor protection when configured according to the motor’s rated data and application requirements.

Flexible Connection Arrangements

The PST175-600-70 supports both in-line and inside-delta installation, subject to the applicable motor and wiring requirements.

Industrial Motor Compatibility

Its 175 A in-line rating makes it suitable for a range of industrial motor applications when the electrical and mechanical requirements are properly matched.

PLC-Based System Integration

The soft starter can be incorporated into automated motor-control systems with appropriate control wiring, protective equipment, and operator interfaces.

Technical FAQs

1. What is the ABB PST175-600-70?

The ABB PST175-600-70 is an advanced soft starter designed for controlled starting and stopping of three-phase AC motors. Its order number is 1SFA894011R7000.

2. What is the rated current of this soft starter?

Its rated operational current is 175 A for in-line connection. For inside-delta operation, the documented rated current is 300 A.

3. What is the operating voltage range?

The main-circuit operating voltage range is 208–600 V AC. The control supply voltage is 100–250 V AC at 50/60 Hz.

4. What is the motor power rating at 400 V?

The rated motor power is 90 kW for in-line connection and 160 kW for inside-delta connection. The appropriate rating depends on the installation arrangement and motor specifications.

5. Can the PST175-600-70 be used with a PLC?

Yes. It can be incorporated into a PLC-based motor-control system through suitable control wiring and supported interfaces. The exact connection method should be confirmed from the wiring documentation.

6. Does this model provide motor overload protection?

Yes. It includes electronic overload protection. Correct motor rated-current settings are necessary for appropriate operation.

7. What is the current-limit adjustment range?

The documented current-limit range is 1.5–7 times the rated current. The setting should provide sufficient motor starting torque while respecting the electrical and mechanical limits of the system.

8. Can it operate in inside-delta configuration?

Yes. The PST175-600-70 supports inside-delta operation, with a documented rated current of 300 A. The motor winding connections and installation must follow ABB’s requirements.

9. What is the weight of the PST175-600-70?

The manufacturer documentation lists the unit weight as 21.5 kg. The supplied product dimensions are 420 × 270 × 360 mm.

10. What should be checked before replacing an existing PST175-600-70?

Verify the main voltage, motor current, power rating, connection method, control supply, wiring, protection settings, and mounting dimensions. Also confirm whether the replacement model supports the required starting and stopping functions.

Procurement and Maintenance Recommendations

When purchasing the ABB PST175-600-70, verify both the model designation and order number. The correct identification is important because ABB offers multiple PST models with different current ratings and electrical configurations.

For new, surplus, or refurbished units, inspect the product label, terminals, housing, and visible electronic components. Request clear photographs and available functional-test information when sourcing equipment for critical production machinery.

Confirm that the supplied unit is complete and that any required accessories are included. Check the control supply requirements and the installation arrangement before ordering a replacement.

For routine maintenance, inspect the power connections, control wiring, cabinet ventilation, and surrounding environment. Loose electrical connections, excessive heat, and contamination can affect equipment reliability.

Keep a record of motor parameters, starting settings, protection settings, and wiring changes. This information can help reduce commissioning time if the soft starter needs to be replaced.

For applications with frequent starts or demanding load conditions, review the starting duty and thermal requirements to ensure the selected soft starter remains within its operating limits.

Conclusion

The ABB PST175-600-70 1SFA894011R7000 is an advanced soft starter designed for industrial three-phase motor applications. It supports a main-circuit voltage range of 208–600 V AC, a rated in-line current of 175 A, and a rated inside-delta current of 300 A.

With adjustable starting and stopping parameters, current limiting, and integrated electronic overload protection, it provides a flexible approach to controlling motor acceleration and reducing starting stress.

For industrial maintenance, replacement, and procurement projects, verifying the complete model number, motor ratings, connection method, and control requirements is essential to achieving reliable system integration.