PowerFlex 520 vs. PowerFlex 750: Which Drive Best Fits Your Application

Rockwell Automation provides solutions for all kinds of applications, from simple to demanding, with their PowerFlex controller. To get the best return on investment (ROI) one must choose a drive that completely solves their problem without features that may be redundant in the context of their applications. Hence, the choice between PowerFlex 520 and PowerFlex 750 drives comes down to understanding their suitability to your application.

Which Drive is Optimal for High vs. Low Power Applications?

The PowerFlex 750 series of controllers is capable of handling very high power requirements. Their configurations support power ratings from 400HP (300 kW) to 2000 HP (1500 kW). The maximum short circuit rating of 200,000 AMP RMS symmetrical makes it an ideal choice for high-load applications in industries. These controllers are available in 400/480 and 600/690 configurations and additionally, there is an AC voltage tolerance up to ±10%. The efficiency rates are up to 97.5%.

On the other hand, the PowerFlex 520 series is more compatible with low-power applications. The power ratings are up to 30 HP (22kW). Their short circuit rating is up to 100,000 Amps, which is appropriate for less demanding applications. The AC voltage tolerance ranges from -15% to +10%. The efficiency is still impressive at 97.5%. The voltage configurations of these drives can be from 100 VAC to 600 VAC.

Which Drive Offers Superior Flexibility in Modular Design?

The PowerFlex 750 has an extensively customizable, advanced modular design. The modular architecture comes with a variety of option slots for various I/O modules and additional communication. This design supports integration with different network protocols, for instance, the dual-port EtherNet/IP option card. There are various packaging options that include factory and field enclosures.

The PowerFlex 520 drives have a modular design with detachable control and power modules. This allows for simultaneous configuration and installation. This design can support two optional communication cards like DeviceNet or PROFIBUS DP. The series supports easy options for mounting. These include DIN rail and panel mounting, with zero stacking allowed up to 45 °C. This makes it suitable for applications where customization is not as needed.

Which Drive Provides Better Performance Optimization?

The PowerFlex 750 drives excel in predictive diagnostics for maintenance and safety options like Safe Torque Off and Safe Speed Monitor. The broader range of option cards, and extensive I/O capabilities add to the versatility.

The PowerFlex 520 series also has features such as removable MOVs for ungrounded systems, relay precharge to limit inrush current, and integral brake transistors. The PWM frequency can be adjusted up to 16 kHz for quiet operations, and there are dual overload ratings for enhanced protection.

Which Drive is Better for Precise Motor Control?

With a number of advanced control methods like Sensorless Vector and Flux Vector control, including feedback options for induction and permanent magnet motors, the PowerFlex 750 drives provide highly accurate control with intermittent overload capabilities for various duty cycles and feature programmable current limits and electronic motor overload protection compliant with N.E.C. Article 430. The decel/accel times are programmable up to 3600 seconds (1 hour) with a 0.1 second step. The overload capability is 110% overload for up to 1 minute in light-duty applications and can be 150% overload for up to 3 seconds in Normal Duty.

On the other hand, the PowerFlex 520 drives also offer reliable motor control with V/Hz and SVC. PowerFlex 525 drives also support Permanent Magnet Motor Control and positioning controls like PointStop and Point-to-Point positioning. The 525 model, with its Closed Loop Velocity Vector Control, achieves an accuracy of ±0.5% across a 60:1 speed range. The drive’s carrier frequency ranges from 2kHz to 16kHz. Although these drives do offer SVC and support PM motor control it does not provide the same precision and breadth of feedback control as the PowerFlex 750. This makes the drive flexible for applications that require moderate precision.

Which Drive Provides More Advanced I/O Wiring and Communication Options?

The PowerFlex 750 series supports various input/output configurations and communication protocols. The drives can be easily integrated with networked systems, thanks to the embedded EtherNet/IP port and optional dual-port EtherNet/IP module. Additionally, there are advanced functionalities like Device Level Ring (DLR) that improve connectivity and redundancy. The other supported communication modules include DeviceNet and PROFIBUS DP.

The PowerFlex 520 series features all the essential I/O options. The 525 model has two analog and seven digital inputs. The embedded EtherNet/IP port is available only in the 525 model. The RS485/DSI communications support multi-drop network configurations. Optional cards such as DeviceNet and PROFIBUS DP are available to extend connectivity options. The overall range is inferior compared to the 750 series of controllers.

Which Drive is More Robust in Terms of Safety Features?

In addition to essential safety features like Safe Torque Off and Safe Speed Monitor, the PowerFlex 750 drives also include predictive diagnostics. This ensures that the drive complies with high safety standards like SIL for both personnel and equipment and has proactive maintenance.

Where the PowerFlex 525 drives do provide basic protection with Safe Torque Off functionality meeting all industrial standards for simple applications, these drives do not include the advanced diagnostic and safety capabilities found in the 750 series.

Which Drive Performs Better in Harsh Environmental Conditions?

The PowerFlex 750 can operate at higher altitudes and temperatures compared to the PowerFlex 520. It can operate up to 9000 meters above sea level (with appropriate derating). It can support surrounding air temperatures up to 50°C without derating.

On the other hand, the PowerFlex 520 drives are designed for normal industrial settings, instead of demanding atmospheric conditions. The drive offers integral filtering for EMC compliance and optional conduit boxes. It supports altitudes up to 4000 metres, and temperatures between -20°C to +60°C (or +70°C with an optional fan kit). These drives are reliable for situations where extreme conditions might not be a primary concern.

Conclusion – which drive is for your application?

The choice between the PowerFlex 520 and PowerFlex 750 drives ultimately comes down to your specific application. Understanding your application is going to be key to making the right choice. However, here are some rules of thumb concluded from the discussion above.

• For smaller and mid-sized operations, the PowerFlex 520 series drives are the better fit for their cost-efficiency and straightforward functionality. The compact design, easy mounting options, and environmental adaptability of the PowerFlex 520 series are usually sought and desired in such general-purpose applications. The series provides adequate motor control, safety features, and connectivity options.
• However, in case your application demands high power, advanced control, and diagnostic capability, the PowerFlex 750 series becomes the optimal choice. Its certified safety systems are better suited for high-demand industrial environments. The extensive communication and I/O options are another add-on that helps with integration into various industrial setups.

Where the PowerFlex 520 is a cost-effective solution for standard applications, the PowerFlex 750 is designed for high-performance needs in demanding environments. Here at DOSupply we carry an extensive catalog of PowerFlex 700 and 500 Series drives ready to be shipped to your workplace. We also offer extensive customer and technical support if you need more assistance picking out a drive for your need, or need to have an existing drive repaired. Feel free to call us today, or if you would like to read more, check out this blog highlighting the PowerFlex 40 series here.