Hardware Comparison: PowerFlex Selection Guide: 523 vs. 525 vs. 527

Allen Bradley Powerflex 520 series drives are an innovative take on modular drive configuration. Common power structures and form factors allow for interchangeability between 3 versions of the 520 series drive, the 523, 525, and 527. Each version adds to the performance options available and allows for easy upgrading of drive systems and reduces maintenance and spares requirements.

There are some common features among the 520 series drives. Common frame sizes, 0.5-30HP power ratings, 100-600V voltage ratings, local HMI’s for programming, and the ability to zero-stack and mount either vertically or horizontally are just some of the more prominent ones.

PowerFlex 523

The 523 series drive is the baseline drive of the 520 series. Available in voltage ranges from 100-600 volts and power ranges from 0.25-30HP, these drives include a local HMI and the ability to add EtherNet/IP capability through a dual-port accessory module, among other things. This is the baseline drive of the family, typically utilizing hardwire controls for operation (the cost of the Ethernet add-on card raises the typical price above the 525.)

PowerFlex 525

The 525 series drive is the mid-range version of the family, adding hardwire Safe Torque Off functionality certified to Sil2/PLd as well as a built in Ethernet port. The 525 drive drops the lowest power ranges, running from 0.5HP – 30HP. This drive is also configurable from the local HMI as well as from CCW. The benefit over the 523 is realized when EthernetIP communications are used to control the drive, reducing the required wiring (usually only the 3 safety and one or two wires to the hardwire controls remain) and reducing the time to install and commission the drive. Two accessory slots are available for inclusion of either a dual port Ethernet card or other higher feature cards for improved motor control.

PowerFlex 527

The 527 series drive is more than just a step up from the 525, it takes the Compact Drive family to another level of motor control. The basic premise behind this drive is using a Kinetix control module to operate a Powerflex 520 series power structure. This creates some interesting and powerful advantages over the 523 and 525, as well as some occasionally frustrating differences in operation and configuration. Additional features over the 525 series include network Safety functions in addition to the hardwire Safe Torque Off, standard dual port Ethernet ports, and integration into Studio 5000 for specific use with Logix family controllers. Power ranges follow the 525 series, going from 0.5HP – 30HP.

Some interesting functionality has been built into these drives, allowing for improvements on the engineering and maintenance aspects of drive use. The ability to program the control module via USB from CCW while separated from the power module allows technicians to quickly open a drive configuration file, download the required configuration into the control module, and replace the control module or entire drive unit and be up and running faster than having to program the drive once it’s installed. Additionally, utilizing the same power structure allows for easy upgrading from 523 to 525 or 527 drives, allowing for integration of networked control and networked safety without having the expense of additional power modules. One of the most interesting features of all this is the ability to program the drive through CCW. This feature, and the ease of which the configuration is completed in CCW, makes programming a drive on commissioning or replacement as easy as: Open CCW, open the configuration file, configure (or check the configuration) and then download. Local configuration can be limited to as little as inputting the network address prior to configuring over the network.

The 527 series drives add some interesting nuances to commissioning. The only function programmable from the local HMI is the network address. Everything else is programmed through network communications through Studio 5000. As the control unit is effectively a Kinetix servo module, the drives are configured as a motion axis in the controller, so a motion capable controller is required (the controller part number needs an “M” near the end of it.) The integrated safety features require a little finagling with the safety functions in the controller (and replacing a drive can cause issues with the drive’s safety signature.) One nice thing AB has done to make these easier to commission is they have created an AOI that allows for configuration and operation like a 525 or 523 drive instead of a servo. The AOI is available from AB online, or from a local distributor.

The differences between the 3 series of drives is significant but once you understand those differences the ingenuity of the family is evident. Swapping between simple drive control to network control and safety is as simple as swapping control modules and programming in the controller. Each series has its own advantages and disadvantages and understanding the requirements of the application and the capabilities of each series is important. Thankfully, the local distributor network for Allen Bradley has experts on these drives, and Allen Bradley tech support is available and knowledgeable (you need to call the Kinetix servo group for the 527 series though, not the drives group.) With the right forethought, these drives can make for a successful implementation and for a reduction in maintenance.

Some notes on the drives:

1. The part numbers are common, 25(A, B, C) for the Powerflex 523, 525 or 527 drives. The numbers after the dash all represent the same things for the different drives, so if you have a 25A-D017N104 and a 25C-D017N104, you have the same power module with a 523 and a 527 control module.
2. The 523 and 525 are programmable via local HMI or through CCW. The 527 is only programmable through Studio 5000 and requires V24 or higher.
3. Grounding of these drives is important. Ensure the grounds are connected per the manual, and that the ground is good. Susceptibility to noise over the ground has been observed, especially when paired with older drives. Symptoms of this are drive trips on high DC bus voltage while the drive is idled, but normal operation while running.
4. The 523 and 525 control modules can be programmed via USB while not powered or connected to a power module. The process is confusing at first, but not difficult. Ask a local distributor to show you how if needed.

Spec	PowerFlex 523	PowerFlex 525	PowerFlex 527
Power Range	0.25-30HP	0.5-30HP	0.5-30HP
Control Type	V/Hz, Sensorless Vector Control	V/Hz, Sensorless Vector Control, Closed Loop Velocity Vector Control, Permanent Magnet Motor Control	V/Hz, Sensorless Vector Control, Closed Loop Velocity Vector Control
Communications	Integral RS485 (ModBusRTU), Optional EtherNet/IP, DeviceNet, or Profibus DP	Integral EtherNet/IP, RS485 (ModBusRTU) Optional Dual Port EtherNet/IP, DeviceNet, Profibus DP	Integral Dual Port Ethernet/IP
Analog Inputs	1 (V or I)	2 (1V, 1I)	2 (1V, 1I)
Analog Outputs	0	1 (V or I)	1(V or I)
Digital Inputs	5(24VDC, 4 programmable)	7 (24VDC, 6 programmable)	4 (24VDC, 3 programmable)
Relay Outputs	1 (form C)	2 (1 form A, 1 form B)	2(1 form A, 1 form B)
Transistor Outputs	0	1	1
Encoder Use	No	1 Incremental, Single or Dual Channel	1 Incremental, Single or Dual Channel
Safety	No	Hardwire Safe-Torque-Off, SIL2/PLd, Cat 3	Hardwire Safe-Torque-Off, SIL3/PLe, Cat3 Network Safety, SIL3/PLe