Product Overview

The ABB PST250-600-70 1SFA894013R7000 Soft Starter is an advanced motor-starting and stopping device designed for controlling large three-phase AC motors in industrial applications. Belonging to ABB’s PST soft starter family, it helps reduce the electrical and mechanical stress associated with direct-on-line motor starting.

When a large motor starts directly across the supply, it can draw a substantial inrush current and produce a sudden increase in mechanical torque. These effects may place additional stress on electrical distribution equipment, motors, couplings, belts, pumps, and other driven machinery. A soft starter controls the voltage applied to the motor during starting, allowing the motor to accelerate more gradually.

The PST250-600-70 is rated for a maximum operational voltage of 600 V AC and a nominal operational current of 250 A for in-line connection. At 400 V, its rated motor power for in-line connection is 132 kW. It also supports inside-delta connection, with a rated operational current of 430 A and a corresponding motor power rating of 220 kW at 400 V.

This model includes advanced motor-starting functions, integrated electronic overload protection, adjustable motor-current settings, programmable ramp parameters, and monitoring outputs. Its control supply operates within a 100–250 V AC range, while the control circuit also supports 24 V DC operation.

The PST250-600-70 is intended for industrial installations where controlled motor acceleration and stopping are important to equipment reliability and process stability. Typical applications include pumps, compressors, fans, conveyors, and other motor-driven machinery.

Technical Specifications

Technical settings and operating limits should be confirmed against the manufacturer’s instructions for the exact installation and operating mode.

Function and Working Principle

The PST250-600-70 controls motor starting and stopping by regulating the voltage supplied to the motor. Rather than applying full line voltage immediately, the soft starter increases the motor voltage according to the configured starting profile.

This controlled process helps reduce the electrical and mechanical impact of motor starting.

1. Controlled Motor Starting

During a direct-on-line start, a motor can draw several times its rated current. The resulting current surge may cause voltage dips in the electrical distribution system and create additional stress on connected equipment.

The PST250-600-70 gradually increases the motor voltage during startup. Engineers can configure the initial voltage and ramp parameters to suit the motor and driven load.

This function is particularly useful for large pumps, compressors, and conveyor systems where sudden acceleration may cause mechanical problems or process disturbances.

2. Adjustable Starting Parameters

The soft starter provides adjustable motor-current and starting parameters. The rated motor current can be configured within the specified adjustment range, allowing the device to be matched to the connected motor.

The starting voltage and ramp settings can also be adjusted to achieve the required acceleration behavior. These parameters should be selected according to motor characteristics, load inertia, starting torque requirements, and the permitted starting time.

3. Soft Stopping

Controlled stopping reduces the abrupt changes that can occur when a motor is disconnected from the supply.

In pumping applications, for example, a sudden stop may contribute to pressure transients and water hammer. A suitable soft-stop profile can reduce the rate at which the motor slows down, helping improve process stability.

The effectiveness of soft stopping depends on the pump system, fluid conditions, motor characteristics, and selected settings.

4. Electronic Motor Overload Protection

The PST250-600-70 includes electronic overload protection. The motor-current setting can be adjusted to match the connected motor’s rated operating requirements.

This function helps monitor motor loading and protect against specified overload conditions. Correct configuration is essential: the soft starter’s overload settings must correspond to the motor nameplate and the application’s operating duty.

Additional protection, such as short-circuit protection and suitable upstream switching devices, must be provided according to the manufacturer’s installation requirements and applicable electrical codes.

5. Bypass Operation

PST soft starters use bypass functionality to reduce power losses during normal running operation. Once the motor has completed its starting sequence, the bypass arrangement can carry the motor current without requiring the power electronics to continuously control the voltage.

The bypass function also supports the soft starter’s thermal operating design. Engineers should verify the actual bypass arrangement and installation requirements in the product documentation.

6. Motor and Device Monitoring

The unit provides operating and fault indications through its status outputs. These signals can be used by a PLC or other control equipment to monitor the motor-starting sequence and respond to abnormal conditions.

Available indications include run, bypass, fault, and overload-related signals. Analog output options can also provide information for monitoring and process-control purposes.

Role in Industrial Control Systems

The ABB PST250-600-70 is typically installed in a motor-control panel as part of a larger electrical and automation system. It provides controlled motor starting and stopping while allowing supervisory equipment to monitor operating status.

PLC Integration

A programmable logic controller can coordinate the soft starter with the rest of the machine or production process.

For example, a PLC may issue a start command after confirming that safety interlocks are satisfied. It can then monitor the soft starter’s run or fault signals and coordinate downstream equipment.

The PST250-600-70 provides status and monitoring interfaces suitable for integration into an industrial control architecture. The precise wiring and signal assignments should be checked against the manufacturer’s terminal documentation.

HMI Monitoring

A human-machine interface can display motor operating status, alarm conditions, and relevant process information.

Operators may use the HMI to initiate permitted operating sequences or identify faults. The HMI typically communicates with a PLC or control system that manages the soft starter’s operating commands and interlocks.

Motor Protection Coordination

The soft starter’s electronic overload protection should be coordinated with the motor’s rated current and the upstream protective devices.

A properly engineered motor-control panel considers the soft starter, circuit breaker or fuses, contactors, motor, grounding system, and control wiring as one coordinated installation.

Process Equipment Coordination

In a production line, the soft starter can help ensure that large motors start in the correct sequence. This is useful when several machines share an electrical supply or when starting one motor affects the operation of other equipment.

PLC logic can use the soft starter’s status signals to coordinate pumps, fans, conveyors, and other motor-driven systems.

Industrial Applications

The ABB PST250-600-70 is designed for large industrial motors and applications that require controlled starting and stopping.

1. Industrial Pumping Systems

Pumps are common applications for soft starters, particularly in water treatment, wastewater handling, industrial cooling, and process-fluid circulation.

A controlled starting sequence can reduce sudden mechanical loading on pump assemblies. Soft stopping may also help reduce pressure transients in suitable pipeline systems.

The PST250-600-70 can be considered for pump motors within its electrical ratings and application limits.

2. Compressors

Large compressors often require careful starting procedures because of their mechanical load and operating characteristics.

A soft starter can help control motor acceleration and reduce the immediate electrical impact of starting. The compressor’s unloading arrangement, starting torque requirements, and permissible starting frequency must be considered when configuring the unit.

3. Industrial Fans and Blowers

Large ventilation fans and blowers may have significant rotating inertia. Starting them directly can create substantial electrical and mechanical stress.

A suitable soft-start profile can provide more gradual acceleration and reduce abrupt changes in mechanical loading.

4. Conveyor Systems

Heavy-duty conveyors may require controlled starting to reduce sudden tension changes in belts, chains, couplings, and gearboxes.

The soft starter can help provide a more gradual motor-starting sequence. For conveyors requiring precise speed adjustment during normal operation, a variable frequency drive may be more appropriate.

5. Industrial Material Processing

Crushers, mixers, and other processing machines may use large motors that benefit from controlled starting. The actual suitability of a soft starter depends on the machine’s breakaway torque, starting load, and required acceleration time.

For high-inertia or high-torque applications, engineers should confirm that the selected starting method can meet the motor and process requirements.

6. Water and Wastewater Facilities

Water and wastewater facilities frequently operate large pumps and blowers. Controlled motor starting can help manage electrical demand and reduce mechanical stress during startup.

The PST250-600-70 can be incorporated into suitable motor-control panels for these applications, provided its ratings and protective coordination meet the project requirements.

Installation and System Integration

Correct installation is essential for safe operation and reliable motor control.

1. Verify the Main Supply

Confirm that the supply voltage is within the device’s specified 208–600 V AC operational range. Check the frequency, phase configuration, motor voltage, and motor rated current before installation.

The motor’s operating current must be evaluated against the applicable in-line or inside-delta rating. Do not select the connection method based solely on the motor’s kilowatt rating.

2. Select the Correct Connection Method

The PST250-600-70 supports both in-line and inside-delta connection arrangements.

For in-line connection, the rated operational current is 250 A. For inside-delta connection, the rated operational current is 430 A.

Inside-delta installation requires a compatible six-lead motor connection and must follow the manufacturer’s wiring instructions. Incorrect connection can cause equipment damage and unsafe operation.

3. Confirm Control Supply Compatibility

The rated control supply voltage is 100–250 V AC at 50/60 Hz. The control circuit also supports 24 V DC operation.

Verify the control supply arrangement and terminal connections before energizing the device. Control wiring should be separated from power wiring where required by the installation design.

4. Provide Adequate Panel Ventilation

The supplied dimensions are 420 × 270 × 360 mm, and the product weight is 23 kg.

Allow sufficient space for mounting, power-cable connections, control wiring, maintenance access, and heat dissipation. The installation should comply with the manufacturer’s clearance and environmental requirements.

5. Configure Motor Parameters

Enter the correct motor rated current and configure the starting voltage, ramp time, overload settings, and other relevant operating parameters.

Incorrect settings may lead to excessive starting current, insufficient starting torque, extended acceleration time, or unnecessary protective trips.

6. Coordinate Protective Devices

Select upstream circuit protection and switching devices according to the manufacturer’s recommendations and applicable electrical standards.

The soft starter’s electronic overload protection is not a substitute for the complete short-circuit protection and isolation arrangement required by the installation.

7. Commission the Motor

Before returning the equipment to service, inspect all power and control connections. Verify motor rotation direction, starting behavior, stopping performance, status indications, and protective functions.

Test the system under appropriate operating conditions and document the final configuration for future maintenance.

Compatible System Components

The PST250-600-70 is normally used with other motor-control and automation components.

The components listed above are examples of equipment used in a complete motor-control system. They are not necessarily included with the PST250-600-70.

Alternative Models and Replacement Considerations

When replacing the PST250-600-70, engineers should compare the complete product number and electrical specifications rather than selecting a device based only on its current rating.

Before choosing a replacement, compare:

• Rated operational voltage.
• In-line and inside-delta current ratings.
• Motor power at the actual supply voltage.
• Control supply voltage and frequency.
• Starting and stopping functions.
• Overload protection and motor-current adjustment.
• Bypass configuration.
• Analog outputs and relay signals.
• Communication requirements.
• Mounting dimensions and cable connections.

A replacement from another product family may require changes to panel wiring, protection coordination, PLC logic, and commissioning procedures.

Key Advantages

Controlled Motor Starting

The PST250-600-70 provides controlled voltage ramping to help reduce the electrical and mechanical impact of motor startup.

High-Current Motor Capability

With a 250 A in-line rating and a 430 A inside-delta rating, the model is designed for large industrial motor applications.

Adjustable Motor Parameters

The adjustable motor-current setting and configurable starting parameters allow engineers to adapt the device to different motor and load conditions.

Integrated Electronic Overload Protection

Built-in electronic overload protection supports motor protection when correctly configured according to the motor’s rated current and application.

Bypass Functionality

The bypass arrangement supports normal motor running after the starting process, helping reduce power losses associated with continuous operation of the starting electronics.

Flexible Monitoring

Run, bypass, fault, and overload signals provide useful information for PLC integration and equipment supervision.

Industrial Application Flexibility

The PST advanced range can be applied to suitable pumps, compressors, fans, conveyors, and other industrial motor-driven machines.

Technical FAQs

1. What is the ABB PST250-600-70?

The ABB PST250-600-70 is an advanced soft starter designed for controlling the starting and stopping of large three-phase AC motors. Its order number is 1SFA894013R7000.

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

Its rated operational current is 250 A for in-line connection and 430 A for inside-delta connection. The correct rating depends on the selected connection method and motor application.

3. What is its motor power rating at 400 V?

For in-line connection, the rated motor power is 132 kW. For inside-delta connection, the rated motor power is 220 kW.

4. What is the operating voltage range?

The rated operational voltage range is 208–600 V AC. The main circuit frequency is 50/60 Hz.

5. What control supply voltage does it require?

The rated control supply voltage is 100–250 V AC at 50/60 Hz. The control circuit also supports 24 V DC operation.

6. Does the PST250-600-70 include overload protection?

Yes. It includes integrated electronic overload protection. The motor-current setting must be configured correctly according to the connected motor’s nameplate.

7. Can this soft starter be used with a PLC?

Yes. Its operating and fault signals can be integrated into a PLC-based control system. The exact wiring and available monitoring signals should be verified using the manufacturer’s terminal documentation.

8. What is the difference between in-line and inside-delta connection?

In-line connection places the soft starter directly in the motor supply circuit. Inside-delta connection places it within the motor winding circuit and requires a compatible six-lead motor arrangement. The rated current and motor power differ between the two configurations.

9. What applications are suitable for this model?

Typical applications include industrial pumps, compressors, fans, conveyors, and other large motor-driven machines requiring controlled starting and stopping.

10. What are the dimensions and weight?

The supplied product dimensions are 420 × 270 × 360 mm, and the weight is 23 kg. These values match the available product technical data.

Procurement and Maintenance Recommendations

When purchasing the ABB PST250-600-70, verify both the model designation and the order number 1SFA894013R7000. The complete identification is important because soft starters in the same product family may have different current ratings, voltage ranges, and control configurations.

For replacement projects, compare the existing unit’s connection method, rated motor current, control supply, terminal arrangement, and protective settings. A unit with the same product-family name is not necessarily an electrically equivalent replacement.

For used or refurbished equipment, inspect the enclosure, power terminals, control terminals, electronic components, and visible signs of overheating or contamination. Where possible, request functional test information and confirm the condition of the bypass and protection functions.

During maintenance, ensure that power connections remain properly tightened according to the specified torque values. Inspect ventilation paths, cabinet temperature, wiring insulation, and control connections. Follow the manufacturer’s maintenance instructions and isolate the supply before performing electrical work.

Keep a record of the motor-current setting, starting profile, overload parameters, and PLC signal assignments. This information can simplify troubleshooting and reduce commissioning time after equipment replacement.

Conclusion

The ABB PST250-600-70 1SFA894013R7000 is an advanced soft starter designed for large three-phase industrial motors. It supports a 208–600 V AC operational voltage range, a 250 A in-line current rating, and a 430 A inside-delta current rating.

With adjustable starting parameters, integrated electronic overload protection, bypass functionality, and monitoring outputs, it can support controlled motor starting and stopping in suitable industrial applications. Accurate motor selection, connection design, protective-device coordination, and parameter configuration are essential for safe and reliable operation.