PowerFlex 70 vs PowerFlex 700

Overview

In the world of industrial automation, Rockwell Automation’s Allen-Bradley PowerFlex family has long served as a benchmark for reliable motor control. Within this legacy portfolio, the PowerFlex 70 and the PowerFlex 700 are two of the most widely deployed variable frequency drives (VFDs) in heavy industry, manufacturing, and municipal infrastructure. While both are built on a similar architecture and utilize the same Drive Peripheral Interface (DPI) protocol, they are engineered for distinctly different performance tiers.

The PowerFlex 70 is a compact, cost-optimized, and versatile drive engineered for simple speed control down to moderately demanding torque control applications. It is designed to be easily integrated into standard MCCs (Motor Control Centers) or mounted directly on machinery where physical space is at a premium.

Conversely, the PowerFlex 700 is a high-performance, heavy-duty industrial drive designed to handle complex, demanding motor control applications. Offering significantly higher power ratings, advanced vector control capabilities, and options for specialized control cartridges, the PowerFlex 700 is built for high-inertia loads, precise speed/torque regulation, and complex system integrations.

As these product lines age—with parts of the PowerFlex 700 family transitioning into the discontinued phase—understanding their precise technical differences becomes critical for maintenance managers, system integrators, and procurement teams looking to maintain operations or plan capital upgrades.

Key Differences at a Glance

While both drives belong to the PowerFlex "7-Class" family, their internal engineering, thermal performance, and hardware expansion capabilities differ significantly.

• Application Scaling: The PowerFlex 70 tops out at 50 Hp (37 kW) in standard industrial environments, whereas the PowerFlex 700 spans up to 1500 Hp (1100 kW) in its vector control configurations, accommodating high-voltage heavy industries.
• Performance Engine: While both offer Sensorless Vector Control, only the PowerFlex 700 features Allen-Bradley’s proprietary FORCE Technology, which delivers patented field-oriented control for exceptional torque regulation at zero speed without encoder feedback (and absolute precision with feedback).
• Enclosure and Form Factor: The PowerFlex 70 features space-saving packaging and includes options for IP66 (NEMA Type 4X/12) washdown ratings, making it ideal for food and beverage applications. The PowerFlex 700 is optimized for cabinet installations (IP20) or high-power open-chassis environments, utilizing larger frame sizes (Frames 0 to 10).

Specifications Comparison

This table details the core engineering and electrical differences between the standard PowerFlex 70 and PowerFlex 700 platforms.

Performance & Capabilities

To understand when to deploy each drive, one must analyze their respective motor control processors. The PowerFlex 70 is designed around a traditional, highly efficient processor optimized for standard machine duties. It delivers excellent Speed Regulation via Sensorless Vector Control (SVC), which develops high starting torque without requiring a motor demagnetization sequence or physical feedback. This makes it a great choice for standard material handling, mixers, fans, and positive displacement pumps.

The PowerFlex 700 operates on a much higher mathematical plane, specifically when deployed with its vector control cassette. Standard FVC (Flux Vector Control) on the PowerFlex 700 provides precise speed control down to zero RPM, making it highly adept at managing hoisting equipment, cranes, and web tensioning systems.

Furthermore, the PowerFlex 700 utilizes FORCE Technology. FORCE (Field-Oriented Rapid Control Expansion) decodes the motor currents into magnetizing and torque-producing vectors, controlling them independently. This yields:

1. Excellent dynamic response to sudden step-load changes.
2. Direct Torque Control (DTC) capabilities for extreme precision in torque-limiting applications.
3. High torque and velocity loop bandwidths.

The PowerFlex 700 also handles higher overload conditions. Standard duty configurations support 110% overload for 60 seconds, whereas heavy-duty engineering allows for 150% overload for 60 seconds and up to 200% for 3 seconds, ensuring the drive does not trip during severe mechanical jams on heavy equipment.

Programming & Software

Rockwell Automation has ensured that both the PowerFlex 70 and 700 maintain a parallel programming interface to simplify shop floor maintenance. Both drives utilize the same Human Interface Modules (HIM)—typically the legacy 20-HIM-A3 or newer 20-HIM-A6 bezel-mounted units. Parameter structures are logically categorized into basic files (such as Motor Data, Ramp Rates, Speed Reference) to make commissioning straightforward on both platforms.

Common Parameter Structure:
[File Folder] -> [Group] -> [Parameter]
Example: [Motor Control] -> [Torq Attributes] -> Net Torque (Par 612 in PF700)

From a software standpoint, both drives can be managed through:

• Connected Components Workbench (CCW): The modern software suite used for configuring, programming, and maintaining Rockwell VFDs.
• Studio 5000 / RSLogix 5000: Through the use of Add-On Profiles (AOP), both drives support Premier Integration. This allows the drive configuration to be stored inside the Logix controller (PLC) project file, enabling Automatic Device Configuration (ADC). If a drive is replaced, the PLC automatically downloads all parameters over the network, dramatically minimizing down-time.

However, because the PowerFlex 700 is designed for high-end applications, its parameter list is much larger (often exceeding 700 distinct registers to configure things like slip compensation, encoder PPR values, torque limits, dynamic braking cycles, and custom I/O mapping).

Communication & Networking

Both drives rely on the Drive Peripheral Interface (DPI) protocol. This internal communication network connects the drive's control board to external communication adapters, HIM modules, and auxiliary cards.

To connect to modern industrial networks, both VFDs utilize Rockwell’s 20-COMM networking modules. Some of the most common cards still active on manufacturing lines include:

• 20-COMM-E: EtherNet/IP adapter (Supports seamless PLC diagnostics and message routing).
• 20-COMM-C: ControlNet adapter (Common in legacy oil/gas and water treatment applications).
• 20-COMM-D: DeviceNet adapter (Used for legacy fieldbus installations).

It is important to note that the PowerFlex 700 has superior structural space to hold these communication modules securely. In the PowerFlex 70 (particularly Frame A and B), installing communication modules requires routing cables and maintaining precise bend radiuses due to the ultra-compact shell, whereas the larger PowerFlex 700 has dedicated channels and internal mounting bays that make physical networking and daisy-chaining easier.

Pricing & Lifecycle

One of the most defining factors for industrial plants choosing between these drives today is lifecycle status.

The PowerFlex 700 is largely discontinued. Rockwell has retired the vast majority of the standard PowerFlex 700 line, marking them as legacy or obsolete. This means obtaining factory-new units through typical distribution channels is difficult, long-lead, or entirely impossible. Consequently, lead times for direct OEM replacements can ground production lines to a halt.

The PowerFlex 70 remains in an Active Mature phase. Rockwell continues to sell and support the PowerFlex 70, but it is heavily targeted for phase-out over the coming decade as the newer PowerFlex 520 and 750 Series take over standard catalog spaces.

[PowerFlex 700]  ======> [Discontinued / Obsolete] ======> Source via Palm Parts Solution
[PowerFlex 70]   ======> [Active Mature]            ======> Upgrade or Maintain Existing

Because of this discontinued status, pricing for the PowerFlex 700 can swing wildly. Industrial plants have a massive financial incentive to keep their existing machinery running. Sourcing high-quality, fully tested refurbished PowerFlex 700 units, replacement control cassettes (such as the standard vector cassette 20B-VECT1-C0), or custom power boards from specialized parts providers like Palm Parts Solution can save plants tens of thousands of dollars compared to forcing an immediate, unscheduled system redesign.

When to Choose Each

Choose the PowerFlex 70 if:

1. Space is Limited: You need to fit a drive inside a standard MCC bucket or a shallow control enclosure.
2. Washdown Environments: Your industry is food, beverage, or pharmaceutical processing, where direct, high-pressure sanitization occurs (PowerFlex 70 IP66/NEMA 4X handles this seamlessly).
3. Pumps & Fans: You are controlling standard, centrifugal loads with low dynamic torque requirements that do not exceed 50 HP.
4. Budget is Constraints: You require straightforward V/Hz speed control with modern EtherNet/IP connectivity without the overhead cost of advanced torque processors.

Choose the PowerFlex 700 if:

1. High Power is Required: The application commands more than 50 Hp (37 kW), reaching up as high as 1500 Hp.
2. Precision Motion/Torque Control: You are regulating web-handling machines, winders, unwinders, paper machinery, or overhead cranes where torque control at zero speed is critical.
3. Heavy Inertia Loads: The mechanical design suffers from high break-away friction or regular load spikes, requiring the 150–200% heavy-duty overload protections.
4. Common DC Bus Systems: You require shared DC bus applications where multiple drives feed into a single regenerative system to conserve electrical energy.

Migration & Upgrade Path

Because of the mature and inactive status of these models, smart facility managers must plan their next moves carefully.

Sourcing Direct replacements

If your control system is heavily integrated with older PLC lines (like SLC 500 or PLC-5) using DeviceNet or ControlNet, upgrading to a brand new-generation VFD requires complete system re-engineering, PLC program rewrites, and fieldbus changes. Under these conditions, the most economical and high-speed option is sourcing certified replacement components. Palm Parts Solution specializes in locating, testing, and supplying legacy PowerFlex 70 and 700 components, allowing you to swap units in minutes rather than spending weeks redesigning automated lines.

Upgrading to the PowerFlex 750 Series

When a migration is physically and financially feasible, Rockwell provides specific upgrade vectors:

• The PowerFlex 70 typically upgrades to the PowerFlex 525 (for general purpose under 30 HP/22 kW) or the PowerFlex 753 (for applications with higher functional safety requirements or larger power ratings).
• The PowerFlex 700 converts directly to the PowerFlex 755 (for integrated motion control on EtherNet/IP) or the PowerFlex 753 (for standard vector control applications).

Note on Migration Physical Footprints: Please note that the PowerFlex 750 Series uses a different dimensional footprint and different mounting patterns. If you migrate from a PowerFlex 70 or 700, budget for wiring alterations, mechanical backplate redrilling, and modifications to your CAD electrical drawings.

Frequently Asked Questions (3-5 Q&A)

Q1: Can I use a PowerFlex 700 standard profile in Studio 5000 if I am replacing a PowerFlex 70?

No. While they share programming paradigms, their I/O maps, configuration parameters, and electronic profiles are different. If swapping a PowerFlex 70 for a PowerFlex 700, you must update your hardware configuration tree in Studio 5000 and download a modified project to the PLC.

Q2: What is the primary cause of fault codes in legacy PowerFlex 700 drives?

Due to age, the most common issues are related to DC bus capacitor degradation (producing Fault 4 - UnderVoltage or Fault 5 - OverVoltage) or localized overheating on the power structure. Purchasing a professionally refurbished unit from specialized suppliers ensures these aged component clusters have been thoroughly inspected and renewed.

Q3: Does the PowerFlex 70 support encoder feedback for closed-loop vector control?

Yes, but it requires a specific, separate feedback option card (such as the 20-HIM or 20-Series encoder modules) and is limited compared to the robust encoder option boards available on the PowerFlex 700, which can accept multiple encoder styles simultaneously.

Q4: Are the communications cards (20-COMM) interchangable between the PowerFlex 70 and PowerFlex 700?

Yes. Both drives utilize Rockwell's DPI communication interface, meaning a 20-COMM-E (Ethernet) or 20-COMM-D (DeviceNet) module can be pulled from a PowerFlex 70 and physically installed on a PowerFlex 700. However, you will need to re-configure the network parameters inside the drive to match the new nodal layout.

Related Articles

• Troubleshooting PowerFlex Drive Faults: A Step-by-Step Guide
• How to Migrate Legacy Allen-Bradley PowerFlex 700 to PowerFlex 755 VFDs
• Understanding FORCE Technology in Modern Industrial Motor Control