PowerFlex 700s: A Practical Guide and Hardware Comparison

PowerFlex drives are a line of VFDs (Variable Frequency Drives) by Allan-Bradely (Rockwell Automation). These drives are employed in the speed and control of electric motors, primarily in industrial applications.

There are various AC and DC drives in the PowerFlex family, such as PowerFlex 4M, PowerFlex 400, PowerFlex 523, PowerFlex 525, PowerFlex 527, PowerFlex 755, PowerFlex 700, PowerFlex 753, and PowerFlex 70. This article focuses on PowerFlex 700 and its hardware with other drive series.

The PowerFlex 700 AC Drive is designed for a wide range of applications, from very simple speed control to torque control of a three-phase induction motor. It offers three series of AC drives: PowerFlex 700, PowerFlex 700S, and PowerFlex 700L.

Key Features of PowerFlex 700 Drives

Some of the features that make PowerFlex a robust and versatile drive for a wide range of applications are;

Voltage Classes and Power Ratings

PowerFlex 700 drives come in the following ranges of power and voltage

• 208/240 V, 60 Hz: 0.5-100 Hp or 0.37-75 kW
• 400 V, 50 Hz:  0.5-670.5 Hp or 0.37-500 kW
• 480 V, 60 Hz: 0.5-700 Hp or 0.37-522 kW
• 600 V, 60 Hz: 0.75 to 110 kW or 1.0 to 150 Hp.
• 690 V, 50 Hz: 0.37 to 132 kW or 0.5 to 200 Hp.

Control

The drive uses various methods for speed control, such as sensorless vectors, volts per hertz, and vector control. Vector control uses Force technology.

Frequency Control

• Speed Regulation with Slip Compensation in the Volts per Hertz Mode has an accuracy of 0.5% of base speed, speed range of 40:1, operating range of 40:1and bandwidth of 10 rad/sec
• Speed Regulation with Slip Compensation in the Sensorless Vector Mode also has an accuracy of 0.5% of base speed but with a speed range and an operating range of 80:1 and a 20 rad/sec bandwidth.
• Speed Regulation with Feedback in the Sensorless Vector Mode achieves an accuracy of around 0.1%, a speed and operation range of 80:1, and a bandwidth of 20 rad/sec.

Speed Control

• Speed Regulation without Feedback in the Vector Control Mode attains a 0.1% accuracy with speed range and operating range of 120:1 and 50 rad/sec bandwidth.
• Speed Regulation with Feedback in the Vector Control Mode achieves 0.001%  accuracy with the same speed range of 120:1 but an operating range of 1000:1 and bandwidth of 250 rad/sec.

Torque Regulation

• Torque Regulation without Feedback has a tolerance or accuracy of ±5% during a bandwidth of 600 rad/sec
• Torque Regulation with Feedback has an accuracy ±2% with bandwidth 2500 rad/sec
  
  

Safety Features

PowerFlex 700 drives have the following certifications for electrical safety:

• CMAA Specification # 70
• NFPA 70
• NEMA ICS 7.1
• IEC 61800-2

Communication Options

There are options for various internal communication modules, such as user-installed kits. These interfaces include the following:

• DeviceNet
• ControlNet
• Ethernet/IP
• Profibus
• Interbus
• Remote I/O
• Serial Communications and other communication networks.

User Interface

Following are the user interface features of the PowerFlex 700:

• Human Machine Interface (HIM) consists of an LCD with multiple lines and status indicators and a keypad with numeric, function, and navigation keys.
• The menu structure is intuitive, and parameters are grouped logically.

Environmental Features

The PowerFlex 700 can operate in varying maximum ambient temperatures without performance derating, with specific conditions for different parts of the drive:

• 0…50 °C (32…122 °F) for general operation.
• 0…40 °C (32…104 °F) for the chassis (heatsink).
• 0…65 °C (32…149 °F) for the control (front of backplane).

There is an ATEX-certified option for drives that operate in explosive environments. The drive is coated in an insulator for protection against moisture, fungus, dust, corrosion, and abrasion.

Hardware Comparison

PowerFlex 700

• Enclosure Sizes: Frame A to E.
• Power Ratings: From 0.5 to 200 HP (0.4 to 150 kW).
• Input Voltage: Low Voltage – 200-240V, 380-480V, and 500-600V and High Voltage – 690V
• Cooling Method: Air-cooled with integral fans.
• Control Interface: LCD Human Interface Module (HIM) and various analog and digital I/O options.
• Communications: Built-in RS485 and optional communication modules for protocols like EtherNet/IP, DeviceNet, and ControlNet.
• Control Modes: V/Hz Control, Sensorless Vector Control (SVC), and Closed Loop Vector Control
• Safety Features: Safe Torque Off (STO).
• Expansion Slots: Up to three expansion slots.

PowerFlex 700S

• Enclosure Sizes: Frame A to E.
• Power Ratings: 0.55 to 1500 kW
• Input Voltage: Low Voltage – 200-240V, 380-480V, and 500-600V and High Voltage – 690V
• Cooling Method: Air-cooled with high-performance cooling fans.
• Control Interface: Advanced LCD HIM and analog and digital I/O options.
• Communications: Multiple built-in and optional communication modules.
• Control Modes: Advanced Flux Vector Control (with or without feedback) and Full Vector Control
• Safety Features: Safe Torque Off (STO) and optional Advanced Safety features
• DriveLogix Integration: Optional DriveLogix module.
• Expansion Slots: More expansion slots compared to the PowerFlex 700.

PowerFlex 700L

• Enclosure Sizes: Compact liquid-cooled design.
• Power Ratings: From 268 to 1310 HP (200 to 980 kW).
• Input Voltage: Low Voltage – 400-480V, and 600V, and High Voltage – 690V
• Cooling Method: Liquid-cooled system.
• Control Interface: LCD HIM and multiple analog and digital I/O options.
• Communications: Supports high-performance communication options.
• Control Modes: Advanced control algorithms, High-performance Vector Control.
• Safety Features: Standard Safe Torque Off (STO) and Optional advanced safety features
• Expansion Slots: Multiple expansion slots.

PowerFlex 4

• Enclosure Sizes: Compact design with sizes ranging from Frame A to B.
• Power Ratings: From 0.2 to 3.7 kW (0.25 to 5 HP).
• Input Voltage:120V, 240V, and 480V
• Cooling Method: Air-cooled with integral fans for smaller drives.
• Control Interface: Basic keypad and display for local control with basic analog and digital I/O.
• Communications: Optional communication modules for protocols like RS485 and Modbus.
• Control Modes: V/Hz Control
• Safety Features: Basic safety features.
• Expansion Slots: Limited or no expansion slots.

PowerFlex 40

• Enclosure Sizes: Compact design with sizes ranging from Frame A to C.
• Power Ratings: Form 0.4 to 2.2kW single phase and from 0.4 to 7.5kW three phase.
• Input Voltage: 120, 240, 480 and 600 V
• Cooling Method: Air-cooled with integral fans.
• Control Interface: It has a basic keypad and display for local control but more advanced analog and digital I/O than PowerFlex 4.
• Communications: Optional communication modules, supporting protocols like DeviceNet, Ethernet/IP, and Modbus.
• Control Modes: V/Hz Control and Sensorless Vector Control (SVC)
• Safety Features: Basic safety features.
• Expansion Slots: Limited expansion options.

PowerFlex 70

• Enclosure Sizes: Available in multiple frame sizes, from Frame A to E.
• Power Ratings: From 0.5 to 50 HP (0.37 to 37 kW).
• Input Voltage: Low Voltage – 208, 240V, 400V, and 480 V and High Voltage – 600V
• Cooling Method: Air-cooled with integral fans.
• Control Interface: LCD Human Interface Module (HIM) and multiple analog and digital I/O options.
• Communications: RS485 and various optional communication modules for different protocols, such as EtherNet/IP, DeviceNet, and ControlNet.
• Control Modes: V/Hz Control, Sensorless Vector Control (SVC), and Closed Loop Vector Control
• Safety Features: Safe Torque Off (STO).
• Expansion Slots: Up to three expansion slots.

PowerFlex 753

• Enclosure Sizes: Frame A to E.
• Power Ratings: From 0.5 to 350 HP (0.37 to 250 kW).
• Input Voltage: Low Voltage – 200-240V, 380-480V, and 600V and High Voltage – 690V
• Cooling Method: Air-cooled with integral fans.
• Control Interface: Enhanced LCD HIM and extensive analog and digital I/O options.
• Communications: RS485 and optional communication modules for EtherNet/IP, DeviceNet, and ControlNet.
• Control Modes: V/Hz Control, Sensorless Vector Control (SVC), and Closed Loop Vector Control
• Safety Features: Safe Torque Off (STO) and advanced safety features (optional).
• Expansion Slots: Up to three expansion slots.

PowerFlex 755

• Enclosure Sizes: Frame A to E.
• Power Ratings: 0.37 to 1400 kW (0.5 to 2000 Hp).
• Input Voltage: Low Voltage – 200-240V, 380-480V, and 500-600V and High Voltage – 690V
• Cooling Method: Air-cooled with fans.
• Control Interface: Advanced LCD HIM and analog and digital I/O options.
• Communications:  Multiple built-in and optional communication modules.
• Control Modes: Advanced Flux Vector Control (with or without feedback) and Full Vector Control
• Safety Features: Safe Torque Off (STO) and optional Advanced Safety features
• DriveLogix Integration: Optional DriveLogix module.
• Expansion Slots: More expansion slots compared to the PowerFlex 753.

Conclusion

It can be concluded that PowerFlex 700, 700S, and 700L provide general-purpose or demanding, high-precision solutions for medium- to high-power applications with intermediate and advanced control features and standard and advanced safety.