Product Overview

The ABB PST105-600-70 1SFA894009R7000 Soft Starter is an advanced electronic motor starting device designed to control the acceleration and deceleration of three-phase AC motors. It belongs to ABB’s PST series, which provides configurable starting and stopping functions for industrial motor applications.

When a conventional motor starter connects a motor directly to the power supply, the motor can draw a high starting current and produce sudden mechanical torque. These conditions may cause voltage disturbances, mechanical shock, belt tension changes, and unnecessary stress on connected equipment.

The PST105-600-70 addresses these challenges by gradually controlling the voltage supplied to the motor during starting. It can also provide controlled stopping, allowing the motor to decelerate more smoothly than with a conventional direct-on-line starter.

This model supports a main-circuit operating voltage range of 208–600 V AC and has a rated operational current of 105 A for in-line connection. At 400 V, its corresponding motor power rating is 55 kW for in-line operation. It also supports inside-delta connection, with a rated current of 181 A and a corresponding 400 V motor power rating of 90 kW, subject to the manufacturer’s application requirements.

The PST105-600-70 is designed for industrial applications where controlled motor starting, adjustable operating parameters, and motor protection are important. Typical installations include pumps, compressors, fans, conveyors, and other machinery driven by three-phase induction motors.

Its advanced control functions make it suitable for motor-control systems that require more than a basic start-and-stop command. Correct selection depends on motor current, starting conditions, load characteristics, connection method, and the required control supply.

Technical Specifications

Electrical ratings depend on the connection method, supply voltage, motor characteristics, and operating duty. Always consult the product documentation when selecting and configuring the starter.

Operating Principle and Control Functions

The PST105-600-70 controls motor starting and stopping through electronic power regulation. Instead of applying full supply voltage immediately, it gradually increases the motor voltage according to the selected starting parameters.

1. Controlled Motor Starting

During a direct-on-line start, a motor can draw several times its rated current. The resulting electrical and mechanical stresses can affect the motor, power distribution system, and driven equipment.

The PST105-600-70 gradually increases the applied voltage during startup. This allows the motor to accelerate more progressively and helps reduce abrupt mechanical movement.

The starting ramp and initial voltage can be adjusted according to the motor and load. Appropriate settings are particularly important for applications involving pumps, fans, compressors, and material-handling machinery.

2. Soft Stopping

The soft-stop function gradually reduces the voltage supplied to the motor rather than disconnecting it immediately.

This can be useful in applications where abrupt stopping may create undesirable mechanical or process effects. For example, controlled stopping can help reduce pressure disturbances in certain pumping systems.

The actual stopping behavior depends on the motor, load inertia, process characteristics, and selected parameters.

3. Current Limitation

The starter provides current-related control functions that help manage the electrical demand during motor acceleration.

Current limitation can be useful when the available power supply has restrictions or when the motor is connected to a distribution system sensitive to high starting currents.

The current limit must be configured carefully. If it is set too low, the motor may not develop sufficient torque to accelerate the load within the required time.

4. Electronic Motor Overload Protection

The PST105-600-70 includes electronic overload protection. This function monitors motor operating conditions and helps protect the motor against excessive thermal loading.

The motor’s rated current and application requirements must be entered correctly. Incorrect settings can reduce protection effectiveness or cause unnecessary interruptions.

Electronic overload protection should be used together with an appropriately designed motor protection and electrical safety system.

5. Adjustable Starting Parameters

The PST series provides adjustable starting and stopping parameters, allowing engineers to adapt motor behavior to different mechanical loads.

Depending on the application, commissioning personnel can configure:

• Initial starting voltage.
• Starting ramp time.
• Current limitation.
• Motor rated current.
• Soft-stop settings.
• Protection and alarm parameters.

The final settings should be established through commissioning tests rather than copied blindly from another motor installation.

Industrial Applications

The ABB PST105-600-70 is designed for industrial three-phase motor applications where controlled starting and stopping can improve equipment operation.

1. Industrial Pumping Systems

Pumps are widely used in water treatment, chemical processing, manufacturing, and industrial utility systems.

When a pump motor starts or stops suddenly, the resulting pressure changes can contribute to water hammer and mechanical stress in the piping system. The soft-start and soft-stop functions can help manage these transitions.

The PST105-600-70 can be considered for compatible pump motors within its current and power ratings.

2. Air Compressors

Industrial compressors often operate under demanding starting conditions. Starting a compressor can require substantial torque, particularly when the mechanical system is not fully unloaded.

A suitable soft starter can help manage motor acceleration and reduce sudden electrical and mechanical loading.

Before selecting the PST105-600-70 for a compressor, engineers should examine the compressor’s unloading arrangement, starting torque, duty cycle, and restart requirements.

3. Industrial Fans and Blowers

Large fans and blowers can have significant rotational inertia. Starting them directly can place additional stress on the motor and mechanical transmission.

The PST105-600-70 can gradually accelerate compatible fan motors, helping reduce sudden torque changes in the drive train.

The required starting time and current settings should reflect the fan’s inertia and ventilation requirements.

4. Conveyor Systems

Conveyor systems are used in manufacturing plants, warehouses, mining facilities, and material-processing operations.

A sudden motor start can cause abrupt belt movement and place stress on mechanical components. Soft starting helps provide a more controlled acceleration profile.

For conveyors with demanding torque requirements or frequent starts, the motor and load must be evaluated carefully to ensure that the selected starter provides sufficient starting performance.

5. Industrial Processing Machinery

Mixers, agitators, crushers, and other process machines may require controlled motor acceleration to reduce mechanical stress.

The PST105-600-70 can be used where its electrical ratings and starting characteristics match the equipment requirements.

Some high-inertia or high-starting-torque applications may require a different starting method or additional engineering evaluation.

Integration into Industrial Control Systems

The PST105-600-70 can be incorporated into a wider motor-control system containing PLCs, operator interfaces, electrical protection devices, and field instrumentation.

PLC Control

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

For example, a PLC may issue a start command when process conditions are satisfied, monitor a running status signal, and stop the motor when a production sequence is complete.

The exact integration method depends on the starter’s installed communication and I/O configuration. Engineers should verify the required interface and available terminals before preparing the control design.

HMI and Operator Monitoring

An HMI can provide operators with access to motor operating information, alarms, and control commands.

In a typical installation, the HMI communicates with the PLC or an appropriate control interface. Operators can then monitor the motor’s operating status and respond to abnormal conditions.

The control design should define which parameters operators may change and which settings should remain restricted to authorized maintenance personnel.

Electrical Protection Coordination

The soft starter is only one part of a complete motor-control arrangement.

A typical installation may also include:

• Upstream circuit protection.
• A suitable isolation device.
• Motor cables and grounding conductors.
• Control power supply.
• PLC or other command equipment.
• Motor thermal protection arrangements where required.
• Emergency-stop and safety circuits designed for the machine.

Protection devices must be coordinated with the motor, starter, cables, and applicable electrical standards.

Installation and Commissioning

Correct installation and configuration are essential for reliable operation of the PST105-600-70.

1. Verify the Electrical Supply

Confirm that the main supply is within the specified 208–600 V AC operating range and that the frequency matches the installation requirements.

The control supply must also be checked separately. This model specifies a control supply range of 100–250 V AC at 50/60 Hz.

Do not assume that the main circuit and control circuit use the same voltage.

2. Select the Correct Connection Method

The PST105-600-70 supports in-line and inside-delta motor connections.

For in-line installation, the starter is connected in series with the motor supply conductors. Inside-delta installation places the starter within the motor winding circuit and requires a compatible motor connection and correctly designed wiring arrangement.

The two connection methods have different current ratings. Confirm the motor terminal configuration and follow ABB’s wiring diagrams before installation.

3. Provide Adequate Cabinet Space

The supplied dimensions are 390 × 186 × 270 mm, and the listed weight is 13 kg.

The control cabinet must provide adequate mounting support, cable access, ventilation, and clearance around the starter.

Because soft starters generate heat during operation, cabinet thermal calculations should account for the device’s operating current, starting frequency, and surrounding equipment.

4. Configure Motor Parameters

Enter the motor’s rated current and other required parameters according to the motor nameplate.

Select suitable starting voltage, ramp time, and current-limit settings based on the load. Incorrect settings may cause long acceleration times, excessive starting current, or failure to start the motor.

5. Check Protection Settings

Review overload protection and other configured protection functions before commissioning.

Protection settings must match the connected motor and operating conditions. They should not be increased simply to prevent nuisance trips without investigating the underlying cause.

6. Perform Commissioning Tests

Before normal operation, verify:

• Main supply voltage and phase sequence.
• Control supply voltage.
• Motor wiring and grounding.
• Correct motor connection method.
• Start and stop commands.
• Starting ramp behavior.
• Motor acceleration and load response.
• Overload and alarm indications.
• PLC or control-system status signals.

Record the final settings for future maintenance and troubleshooting.

Compatible System Components

The PST105-600-70 is normally installed as part of a complete motor-control system.

The components listed above are examples of equipment used in a motor-control installation. They are not necessarily included with the PST105-600-70.

Advantages of the ABB PST105-600-70

Reduced Starting Stress

Gradual voltage control helps reduce abrupt motor acceleration and can lower mechanical stress on connected equipment.

Controlled Stopping

The soft-stop function provides a controlled voltage reduction, which can be useful in applications where sudden motor stopping is undesirable.

Flexible Motor Configuration

Support for in-line and inside-delta connections gives engineers additional flexibility when designing compatible motor-control systems.

Integrated Overload Protection

Electronic overload protection helps monitor motor loading and supports protection against excessive thermal conditions when correctly configured.

Adjustable Starting Parameters

Configurable starting voltage, ramp time, and current-related settings allow the starter to be adapted to different motor and load characteristics.

Industrial Motor-Control Application

Its 105 A in-line rating and 181 A inside-delta rating make it suitable for a range of medium-to-large industrial motor applications, subject to the relevant operating conditions.

Technical FAQs

1. What is the ABB PST105-600-70?

The ABB PST105-600-70 is an advanced electronic soft starter designed to control the starting and stopping of three-phase AC motors. Its order number is 1SFA894009R7000.

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

Its rated operational current is 105 A for in-line connection. For inside-delta connection, the rated operational current is 181 A.

3. What is the maximum operating voltage?

The main circuit operating voltage range is 208–600 V AC. The actual supply voltage must be compatible with the motor and installation design.

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

For in-line connection, the corresponding motor power rating is 55 kW. For inside-delta connection, the corresponding rating is 90 kW.

5. What control voltage does the PST105-600-70 require?

The specified control supply range is 100–250 V AC at 50/60 Hz. Confirm the control supply requirements before wiring the unit.

6. Does this soft starter support soft stopping?

Yes. The PST series provides controlled stopping functions that gradually reduce motor voltage according to the configured parameters.

7. Does it include motor overload protection?

Yes. The PST105-600-70 includes integrated electronic overload protection. Correct motor-current settings are necessary for appropriate protection.

8. Can the PST105-600-70 be used with a PLC?

Yes. It can be integrated into an industrial automation system using a suitable control interface. The exact wiring and communication method depend on the installed configuration and control-system design.

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

In-line connection places the starter in series with the motor supply. Inside-delta connection places it within the motor winding circuit. The two arrangements have different current ratings and wiring requirements. The motor must support the selected connection method.

10. What should be checked before replacing an existing PST105-600-70?

Verify the complete order number, voltage range, current rating, control supply, motor connection, wiring arrangement, and configured parameters. Also inspect the cabinet space and control-system interfaces to ensure that the replacement is suitable.

Maintenance and Procurement Recommendations

When purchasing an ABB PST105-600-70, confirm that the product label shows the correct model and order number, 1SFA894009R7000. This is particularly important for replacement projects involving existing motor-control cabinets.

For new, surplus, or refurbished equipment, request clear photographs of the nameplate, terminals, and exterior condition. Confirm the product’s storage or operating history where available and check whether accessories or installation documentation are included.

During routine maintenance, inspect electrical connections, cable insulation, grounding, ventilation openings, and the surrounding cabinet environment. Check for signs of overheating, contamination, or abnormal operating conditions.

If the starter repeatedly trips, investigate the motor current, load conditions, acceleration settings, supply voltage, and protection configuration before returning the equipment to service.

For replacement applications, do not select another soft starter based only on a similar current rating. Compare the voltage range, connection method, starting duty, control supply, protection functions, and PLC interface. A replacement from another ABB series may require wiring changes or a new commissioning procedure.

Conclusion

The ABB PST105-600-70 1SFA894009R7000 Soft Starter is an advanced motor-control device designed for industrial three-phase AC motors. With a 105 A in-line rating, a 181 A inside-delta rating, and a main circuit voltage range of 208–600 V AC, it supports controlled motor starting and stopping across a range of industrial applications.

Its adjustable starting parameters, soft-stop capability, and integrated electronic overload protection make it suitable for properly engineered pump, compressor, fan, conveyor, and process-machinery installations.

For maintenance and replacement projects, confirming the exact model, electrical ratings, connection method, and control requirements is essential to achieving reliable motor operation.