PowerFlex 700H vs PowerFlex 700S: Which Drive Fits Your Applications

With most of the present-day industries adopting advanced industrial automation technologies, selecting the right Variable Frequency Drive (VFD) or AC drive for a given application is critical. A well-matched AC drive helps improve system performance, reduce power consumption, minimize unplanned downtime, and extend the service life of the equipment. The Rockwell Automation PowerFlex Series offers a wide variety of flexible, reliable, and user-friendly AC drives designed to control AC motors in a range of industrial automation applications.

In this article, we’ll compare the PowerFlex 700H vs PowerFlex 700S AC drives, focusing on their key features, motor control capabilities, application suitability, power ratings, communication options, and safety features. Understanding these aspects will help you determine which of the two PowerFlex AC drive series is ideal for your specific motor control needs.

PowerFlex 700H Overview

The Allen-Bradley PowerFlex 700H AC drives are designed for automation applications that require simple motor speed control and reliable performance. The drives offer a cost-effective, space-saving solution for variable-speed control solution. They are available in power ratings of 200 to 1900 HP (132 to 1200 kW) at 480V AC input, 160 to 2000 kW at 690V AC input, and 150 to 2400 HP at 600V AC.

The drives can be configured for either Vector Control (SVC) or Volts per Hertz (V/Hz) motor control modes to meet an extensive range of application needs. These motor control algorithms ensure reliable motor operation without the requirement for feedback devices. The PowerFlex 700H control module is standard across all the available drive ratings and is separately detachable from the power structure, which simplifies installation and maintenance of the entire PowerFlex 700H product line. The drives are also available with optional I/O modules, offered at 115V AC or 24 volts DC. Standard enclosure choices for these drives include IP20 NEMA, UL Type 1, and flange mount options, allowing for greater installation flexibility.

PowerFlex 700H AC drives support a variety of industrial communication protocols via user-installed kits, allowing for seamless integration with various Allen-Bradley Logix controllers. Supported protocols include Ethernet/IP, ControlNet, Interbus, DeviceNet, Remote I/O, Profibus, and Serial communications (e.g., RS-232/485), among other open communication and control networks. The listed communication interfaces enable fast and efficient motor control and/or data exchange with host Logix controllers.

Key Features              

PowerFlex 700H AC drives are available with the following key features:

• Versatile Motor Control: The drives offer both Volts-per-Hertz and Sensorless Vector motor control modes, allowing users to choose the best control configuration for their application.
• User-friendly Interface: PowerFlex 700H drives include a full-featured, intuitive LCD Human Interface Module (HIM) with a multi-line, multilingual display that makes drive programming, monitoring, and troubleshooting easier. The HIM features a 21-character  7-line backlit LCD, alternate function keys for rapid access to common tasks, and a numeric keypad for easy data entry.
• Modular Design: A modular design that features a removable control module that is standard across all the PowerFlex 700H drive ratings, which makes installation and maintenance easier.
• Flexible I/O and Communication Options: Features integral standard I/O whose functionality can be extended with optional 24V DC or 115V AC digital and analog I/O. Supports a variety of optional internal communication modules, including EtherNet/IP, Remote I/O, ControlNet, DeviceNet, Profibus, Serial communications, and Interbus modules.
• Optimized Voltage Settings: PowerFlex 700H AC drives are engineered to meet global standards with optimized global voltage settings, which facilitate quick setup and ensure compatibility across various regions.

Benefits

Here are the benefits of using a PowerFlex 700H AC drive:

• Improved Performance: With a choice of two robust motor control algorithms and capabilities to provide excellent torque at low motor speeds, the PowerFlex 700H drives are suited for demanding speed control applications.
• Simplified Installation and Maintenance: The PowerFlex 700H modular design, which includes a removable control module, streamlines the installation and maintenance processes, decreasing downtime.
• Seamless Integration: With a wide choice of communication options, PowerFlex 700H AC drives integrate seamlessly into existing automation systems, allowing for fast and efficient data transmission and motor control.
• User-Friendly Operation: The intuitive LCD HIM and PC-based software tools simplify PowerFlex 700H configuration and monitoring, shortening the learning curve and increasing operational efficiency.

PowerFlex 700S Overview

The Allen-Bradley PowerFlex 700S AC drives are intended for high-performance automation applications that require advanced motor control capabilities. They offer a wider power range compared to the PowerFlex 700H, but they support the same voltage classes. Their power ratings are as follows:

o    200 to 240V AC input: 0.5 to 100 Hp / 2.2 to 260 A / 0.37 to 66 kW

o    380 to 480V AC input: 0.5 to 200 Hp / 1.1 to 260 A / 0.37 to 132 kW

o    500 to 600V AC input: 1.7 to 144 A / 1 to 150 Hp

o    690V AC input: 52 to 142 A / 45 to 132 kW

PowerFlex 700S AC drives use advanced motor control algorithms, including Flux Vector Control and the Allen-Bradley FORCE Technology, to precisely control induction and permanent magnet motors. They also feature an integrated position loop, which makes them ideal for high-precision positioning applications, such as indexing and electronic line shaft operations. They are available with a choice of IP20 NEMA or UL Type 1 enclosure ratings, just like the PowerFlex 700H AC drives.

In addition, like the PowerFlex 700H, the PowerFlex 700S AC drives also support a variety of optional internal communication adapters, including Remote I/O, Interbus, ControlNet, Profibus, DeviceNet, and various Serial communication modules. They are also available with an optional 21-character  7-line backlit LCD HIM, which facilitates drive programming, configuration, and troubleshooting.

One notable feature of the PowerFlex 700S drive series is the optional DriveLogix module, which integrates a Logix-based Allen-Bradley controller directly into a PowerFlex 700S drive, offering embedded programmability for complex control tasks.

Key Features

PowerFlex 700S AC drives are available with the following key features:

• Advanced Motor Control Algorithms: The drives can be configured for Volts-per-Hertz (V/Hz) control, Vector Control with Allen-Bradley FORCE Technology, and Permanent Magnet Motor Control, providing high-performance motor control with excellent speed and torque management. The mentioned motor control modes are essential in applications that require rapid dynamic reaction and high accuracy.
• Built-in Diagnostic Tools: PowerFlex 700S AC drives are equipped with inbuilt diagnostic tools that include advanced features such as fault codes, parameter monitoring (for monitoring key parameters like temperature, voltage, and motor current), and predictive diagnostics, allowing users to readily identify potential faults and carry out preventative maintenance early enough before extensive failures occur.
• Modular Design: PowerFlex 700S drives feature a modular structure designed to be scalable, allowing for easy expansion and modification. Users can choose from a variety of option modules to meet their specific communication, feedback, and I/O needs. This makes the drives adaptable to a wide range of industrial automation applications.
• Enhanced Communication Options: PowerFlex 700S drives support a variety of industrial communication protocols, including EtherNet/IP, ControlNet, and DeviceNet, which enhances networking flexibility. This adaptability allows for seamless integration of the drives into existing network infrastructures, facilitating efficient data transmission and motor control.
• Space-saving Design: The PowerFlex 700S drive series features an innovative, bookshelf space-saving design that allows zero-stacking (side-by-side placement of drives without additional separation) of the PowerFlex 700S drives. This feature helps save considerable panel space and lower installation costs.
• Pull-Apart Control Terminal Blocks: These terminal blocks allow for easy wiring and quick disengagement, simplifying drive installation and maintenance.
• Embedded Control Capabilities: When integrated with an optional DriveLogix controller, the PowerFlex 700S drives combine the functionality of an AC drive and a Programmable Logic Controller. This integration enables smooth execution of complex control tasks without the need for additional control hardware.
• Flexible Programming and Configuration: PowerFlex 700S AC drives support multiple controller programming languages, such as Ladder Logic, Sequential Function Chart, Function Block Diagram, and Structured Text. This programming versatility allows for the implementation of complex control strategies that can be tailored to specific application requirements.
• Global Compatibility: PowerFlex 700S drives are available with optimized global voltage settings that enable easy setup and operation worldwide, allowing seamless integration of the drives into different automation systems globally.
• Common Bus Capability: The PowerFlex 700S drive series supports both AC and DC common bus topologies, allowing effective energy transfer across different drives within an automation system.
• SynchLink Communications: PowerFlex 700S drives do support SynchLink — a fiber optic communication interface that allows the drives’ users to implement distributed motion control. The link enables high-speed drive coordination and data transfer, making PowerFlex 700S drives ideal for applications that require synchronized operations.

Benefits

Here are the benefits of using a PowerFlex 700S AC drive:

• Improved Operational Efficiency: The advanced motor control algorithms and integrated DriveLogix controller minimize the need for additional control hardware, simplifying the PowerFlex 700S system architecture and enhancing operational efficiency.
• Reduced Downtime: Comprehensive diagnostics and real-time monitoring enable proactive maintenance, reducing unexpected outages and increasing equipment longevity.
• Application Versatility: The PowerFlex 700S multiple programming options and modular architecture make the drive series appropriate for a broad range of automation applications, including simple speed control and complex coordinated motion systems.
• Simplified Integration: Because PowerFlex 700S drives support a variety of communication protocols, they can readily be integrated into an extensive array of control systems, saving considerable engineering time and costs on system setup.
• High-Precision and Performance: The advanced motor control modes and high-speed coordination of PowerFlex 700S features enable precise motor control, making the drives ideal for demanding automation applications that require high-precision speed and torque management.
• Space and Cost Savings: The Zero Stacking PowerFlex 700S design and integrated control options help reduce the drives’ physical footprint and eliminate the need for extra control hardware, which results in significant cost savings during installation and maintenance.
• Simplified Maintenance: Features such as pull-apart terminal blocks and user-friendly HIM interfaces make drive maintenance much easier, minimizing system downtime and operational disruptions.
• Global Applicability: The PowerFlex 700S optimized voltage settings and compliance with international standards make these Allen-Bradley AC drives an adaptable motor control solution for global operations, providing consistent performance across different regions in the world.

Technical Specifications and Key Features Comparison

Electrical Specifications:

• Input Voltage and Power Range: PowerFlex 700H drives are optimized for 400V and 690V AC operations, with power ratings suitable for many industrial applications. PowerFlex 700S drives are designed for similar voltage ratings, but they are generally available in power ratings and configurations that allow for a wider range of control and integration applications.
• Operating Efficiency & Thermal Performance: Both PowerFlex drive series are designed for high-efficiency operation (up to 97.5% at rated conditions), featuring integrated EMC filtering and advanced thermal management technologies that ensure operational reliability and system longevity.
• Overload and Derating: Both PowerFlex drive series can readily handle intermittent overloads, although the PowerFlex 700S advanced control algorithms can provide better motor control under low voltage or high thermal conditions, according to manufacturer documentation.

Motor Control Techniques and Algorithms:

• Control Algorithms: PowerFlex 700H AC drives support robust V/Hz and Sensorless Vector control. This combination provides dependable performance in a variety of industrial applications, particularly when encoder feedback is not critical. On the other hand, PowerFlex 700S AC drives provide Field-Oriented (Vector) Control using the Allen-Bradley FORCE technology in addition to V/Hz and Sensorless Vector Control. This approach provides greater dynamic responsiveness, including outstanding speed regulation and precise torque control.
• Feedback and Encoder Integration: PowerFlex 700S AC drives incorporate encoder feedback for closed-loop control, enhancing positioning tasks and load handling in high-precision or variable-load applications.
• Stand-Alone Operation: The optional DriveLogix controller available with PowerFlex 700S drives can integrate auxiliary control operations without an additional Allen-Bradley PLC, which simplifies system architecture in some applications.

Safety Features

• Safe Torque Off (STO): Both PowerFlex 700H and PowerFlex 700S drives series provide the Safe Torque Off functionality. The PowerFlex 700S drives are, however, designed to meet more stringent safety standards (PLd/SIL2 Cat 3). They also include integrated diagnostic and fault detection mechanisms that instantly shut off the drive output for operator safety.
• Fault Diagnostics and Predictive Maintenance: The PowerFlex 700S drives utilize advanced inbuilt diagnostic tools, such as parameter monitoring, fault codes, and predictive diagnostics, to provide real-time monitoring of motor and drive performance. Improved fault memory and predictive diagnostics help to reduce downtime and simplify maintenance scheduling.

Communication and Integration

• Interface Options: Both PowerFlex 700H and PowerFlex 700S drive series support a wide array of industrial communication protocols (e.g., EtherNet/IP, DeviceNet, Profibus, ControlNet, Interbus, etc.).
• Integration Flexibility: The additional embedded control and networking features (such as dual-port Ethernet options in some configurations) that are available with the PowerFlex 700S drive series make it particularly well-suited for applications requiring tight integration with existing control systems.
• Modular Expansion: Both PowerFlex AC drive series come with option slots for additional modules such as safety I/O, auxiliary control power, and encoder interfaces, enabling future-proofing and scalability.

Application Suitability

• PowerFlex 700H Applications: The drives are an ideal choice for industrial applications where robust, reliable performance is needed without the requirement for ultra-high precision feedback control. Commonly used in pumps, fans, and general process control applications.
• PowerFlex 700S Applications: They are best-suited for applications demanding high precision and dynamic performance, such as machine tools, conveyors with variable load conditions, and systems that benefit from integrated control of auxiliary functions. Their capability to control permanent magnet motors is an added advantage in modern high-efficiency systems.

Conclusion

The decision to choose either a PowerFlex 700H or PowerFlex 700S AC drive should be primarily based on the specific needs of your application. The PowerFlex 700H provides reliable performance for general-purpose control applications with moderate speed regulation requirements. In contrast, the PowerFlex 700S boasts more advanced control features, greater speed regulation capabilities, and a wide range of feedback options, making it perfect for complex, high-precision control applications.

No matter which drive you decide is best for your operations, you can rest easy knowing that you’re buying quality and reliability when picking AB. Though if you have a specific drive in mind, why not check us out at DOSupply.com, where we probably have what you need and more. We’re just an email or a phone call away from elevating your automation experience. If you would like to read more, we have an article on how to extend the life of your PowerFlex 700 drive here.