PowerFlex 4M vs PowerFlex 4

Overview of PowerFlex 4 

The Allen-Bradley PowerFlex 4 is a series of compact Variable Frequency Drives (VFDs), which provide powerful and precise motor speed control. These drives are programmed for Volts-per-Hertz (V/Hz) operation mode, as the default motor control setting. They are designed for ease of use and optimal flexibility, with a space-saving design. In addition, PowerFlex 4 drives provide users with intuitive interface devices including an integrated keypad with control keys and a local potentiometer.

Moreover, the PowerFlex 4 drives are an economical speed control alternative for a variety of industrial applications including fans, conveyors, machine tools, pumps, and material handling systems. Essentially, PowerFlex 4 drives are designed to meet the demands of global Original Equipment Manufacturers (OEMs) and end-users for simplicity, cost efficiency, and space savings. They are the smallest and most cost-effective members of the compact, Allen-Bradley PowerFlex® inverter drives.

Note: The Catalog drive code for Allen-Bradley PowerFlex 4 series is 22A-xxxxxxxx 

PowerFlex 4 drives are available in power ratings ranging from 0.25 to5.0 Hp (0.2 to 3.7 kW), and the corresponding input voltage classes are as follows: 

• 100V AC to 200V AC: 0.25…1.5Hp (Horsepower) or 0.2 …1.1kW (Kilowatts). Current rating 1.5…6 A(Amperes) 
• 200V AC to 240V AC: 0.25…5 Hp or 0.2…3.7 kW. Current rating 1.4…17.5 A 
• 380V AC to 480V AC: 0.5…5 Hp or 0.4…3.7 kW. Current rating 1.4…8.7 A 

Overview of PowerFlex 4M  

For retrofit applications, the new Allen-Bradley PowerFlex 4M class of Adjustable Frequency Drives (AFDs) from Rockwell Automation, provides users with performance-enhancing and flexible motor control options. PowerFlex 4M AC drives offer powerful Volts-per-Hertz (V/Hz) motor control in a compact, space-saving design.

They are engineered for ease of programming, providing global OEMs and panel builders with cost-effective, variable frequency motor control with feed-through power wiring for quick drive setup. In addition, PowerFlex 4M are easy-to-use AC drives that allow users to increase application flexibility and minimize mechanical machine stress.

Note: The Catalog drive code for Allen-Bradley PowerFlex 4M series is 22F-xxxxxxxx

PowerFlex 4M AC drives are available in power ratings ranging from 0.2 kW to 11 kW, with voltage classes of 120V, 240V and 480V, as outlined below: 

• 100V AC to 200V AC: 0.25…1.5 Hp (Horsepower) or 0.2 …1.1 kW (Kilowatts). Current rating 1.6…6 A (Amperes) 
• 200V to 240V: 0.25…10 Hp or 0.2…7.5 kW. Current rating 1.6…33 A 
• 380V to 480V: 0.5…15 Hp or 0.4…11 kW. Current rating 1.5…24 A 

What Differentiates a PowerFlex 4M From a PowerFlex 4? 

When choosing between either a PowerFlex 4M or PowerFlex 4 AC drive, one needs to take into account the primary differences between the two. This section entails an in-depth comparison of the features and functionalities of PowerFlex 4M and PowerFlex 4. 

A) Motor Control Type

By default, both PowerFlex 4 and PowerFlex 4M drives are programmed for Volts per Hertz (V/Hz) operation mode. With V/Hz motor control mode, a constant ratio is maintained between the supply voltage (V) and frequency (Hz). Thus, varying the frequency of the supply voltage affects both the strength of the motor’s magnetic field and the motor speed. For example, when the supply voltage frequency is reduced for slower motor speeds, the magnetic field increases leading to the generation of excessive heat.

On the other hand, increasing the voltage frequency reduces the strength of the magnetic field, as the speed of the motor increases. In Volts/Hertz mode, a single PowerFlex 4 or PowerFlex 4M drive can be used to control multiple motors.

In addition, both PowerFlex 4M and PowerFlex 4 AC drives also have a drive automatically functionality that provides Slip Compensation and Auto Boost (IR Compensation). This feature provides improved speed regulation even with increasing loading. It also offers high levels of torque and excellent speed regulation across the entire speed range of the PowerFlex drive. PowerFlex 4 drives have four preset speeds, similarly PowerFlex 4M drives also have four preset speeds. The two drive series require a control voltage of 24V Sink/Source, and they both provide open-loop speed regulation only.

B) Power Wiring

PowerFlex 4M drives have feed-through wiring, in which the line voltage is connected to the top of the AC drive while the motor is connected to the bottom of the same drive. Configuring PowerFlex 4M drives using feed-through wiring enables users to easily upgrade from motor-starter control to AC drive control, as the user can readily mimic the original power wiring configuration. Thus, the upgrade can consist of just swapping out the motor starter for the PowerFlex 4M drive and keeping the associated circuit protection and control wiring.

On the contrary, PowerFlex 4 drives have bottom-fed wiring, in which the line voltage and the motor terminate at the bottom of the AC drive.

C) Inputs/Outputs

The I/O configuration for PowerFlex 4M and 4 drives is as outlined in the table below: 

Inputs/Outputs	PowerFlex 4 Drives	PowerFlex 4M Drives
Standard Digital Inputs	5…24V Sink/Source Three(3) Fixed – Start/Stop/Reverse, Two(2) Fully Programmable	5…24V Sink/Source Three(3) Fixed – Start/Stop/Reverse, Two(2) Fully Programmable
Analog Inputs	One (1) Unipolar input, selectable for either voltage input (0…10V), or current input (0…20 mA)	One (1) Unipolar input, selectable for either current input (0-20 mA), or voltage input (0-10V)
Digital Outputs	One(1) Form C Relay Output	One(1) Form C Relay Output
Analog Outputs	NO	NO

Both PowerFlex 4 and PowerFlex 4M drives have a digital input scan time of 2 ms (milliseconds), a 10-Bit analog input resolution, and an analog input scan time of 12 ms (milliseconds). Note, that this input scan time is not throughput time. Also, both analog output resolution and analog output scan time are Not Available with the two PowerFlex drive series.

D) Frame Sizes

Allen-Bradley PowerFlex 4M AC drives are available in three frame sizes: A, B and C. The measurements for the three frames are as follows: 

• PowerFlex 4M A-Frame: 174mm (Height) x 72mm (Width) x 136mm (Depth) 
• PowerFlex 4M B-Frame: 174mm (Height) x 100mm (Width) x 136mm (Depth) 
• PowerFlex 4M C-Frame: 260mm (Height) x 130mm (Width) x 180mm (Depth) 

Conversely, the Allen-Bradley PowerFlex 4 drive series is available in two frame sizes: A and B. The two frames measure the following: 

• PowerFlex 4 A-Frame: 152mm (Height) x 80mm (Width) x 136mm (Depth) 
• PowerFlex 4 B-Frame: 180mm (Height) x 100mm (Width) x 136mm (Depth) 

E) Installation

For ease of installation, the PowerFlex 4M A-and B-Frame drives are designed with simple DIN-rail mounting features that enable virtual snap-in installation. Similarly, PowerFlex 4 Frame A and Frame B drives include DIN rail mounting features, for virtual snap installation.

In addition, Panel mounting is also available with the two drive series, providing additional installation flexibility. The PowerFlex 4 series also includes a Flange mount and Plate mount drives. Compared to conventional screw-in mounting, installing a DIN-rail-compatible PowerFlex 4 or PowerFlex 4M drive is significantly more time-efficient.

F) Enclosure Types

PowerFlex 4 drives are available with various types of enclosures, including: (i) IP20, NEMA/UL Open Type enclosure; (ii) IP30, NEMA/UL Type 1 enclosure (with optional conversion kit); (iii) IP40/54/65, NEMA Type 1/12/4/4X enclosures.

In contrast, PowerFlex 4M drives are available with only one type of enclosure: IP20, UL/NEMA Open Type Enclosure. In addition, all PowerFlex 4 frame sizes include a Heatsink Out the Back. However, PowerFlex 4M drives do not include a Heatsink Out the Back.

G) Zero Stacking

All frame sizes of PowerFlex 4M and PowerFlex 4 drives feature Zero-Stacking, with an allowable maximum ambient temperature of up to 40℃ (104℉). Zero-Stacking allows the saving of valuable panel space because stacking PowerFlex 4 or 4M drives side-by-side eliminates any space between those drives.

H) Operating Temperature Range

The ambient operating temperature range for IP20 rated PowerFlex 4M and PowerFlex 4 is between −10℃ to 50℃, with minimal spacing between the drives. For IP20 Zero Stacking™ PowerFlex 4M and 4 AC drives, the operating ambient temperature should range from −10℃ to 40℃. In addition, any PowerFlex 4M or PowerFlex 4 drive that’s not in use should be stored within an ambient temperature range of −40℃ to 85℃.

I) Communications

PowerFlex 4M and PowerFlex 4 drives are available with One (1) integral RS-485 serial port as a standard feature. This port enables internal RS-485 communications. Modbus RTU is the standard protocol used to implement RS-485 communications in the two drive series. Thus, all PowerFlex 4 and 4M drive ratings are compatible with any device functioning as an RTU Master, and that supports standard 06 and 03 RTU commands. 

Also, PowerFlex 4 and 4M AC drives include a Serial Converter Module (RS-485 to RS-232) with Cat. No. 22-SCM-232. This SCM provides serial connectivity via DF1 protocol to any controller that can initiate DF1 messaging such as RS-232/DF1 to RS-485/DSI communications. Note, the Serial Converter Module can be eliminated whenever the controller being used acts as an RTU Master.  

The module can also be used with PC-based software. A smart Serial Converter (RS-232) that’s self-powered includes the following: 

• One (1) DSI to RS-232 serial converter 
• One (1) 22-RJ45CBL-C20 Cable 
• One (1) 1203-SFC Cable 

With integral RS-485/DSI communications you can use PowerFlex 4 and 4M AC drives in a multi-drop network configuration. 

In addition, you can include optional integral communication cards in your PowerFlex 4 or PowerFlex 4M drive to improve machine performance. These cards can only be used with an external DSI communications kit for 22-X-COMM adapters and a DC-BASE external mounting kit. The optional communication cards that are compatible with PowerFlex 4 and 4M drives include:

• EtherNet/IP™ 
• ControlNet™ 
• DeviceNet™ 
• BACnet® 
• PROFIBUS™ DP 
• LonWorks® 

Moreover, PowerFlex 4 and 4M AC drives can support USB communications with a Universal Serial Bus™ (USB) Converter. This converter provides direct and isolated USB connections for use with PC-based software. Note, the USB converter should include a USB cable (2.0 meters long), a 22-HIM-H10 cable, and a 20-HIM-H10 cable.

J) Drive Setup

For ease of drive setup and information sharing, the integral RS-485 communications provided by PowerFlex 4M and PowerFlex 4 drives enable system engineers to use those drives in a multi-drop network configuration. For added programming and control flexibility, PowerFlex 4 and 4M drives feature an integrated LCD keypad, a UL/NEMA Type 4X remote, and UL/NEMA Type 1 handheld LCD keypad with a CopyCat function. Thus, the two PowerFlex drive series can be programmed and configured via the local integral LCD keypad, or the remote keypad.

Furthermore, users can also program, monitor, and control PowerFlex 4M and PowerFlex 4 drives with PC-based programming tools. Also, the programming of PowerFlex 4 and 4M drives is greatly simplified through the use of the Serial Converter Module, which provides connectivity to controllers with a DF1 port.

K) Standards and Certifications

PowerFlex 4 and 4M AC drives are compliant with various standards, and they include different certifications, namely: 

• UL (Underwriters’ Laboratories) listed 

• RCM (Regulatory Compliance Mark) marked 
• CSA(Canadian Standards Association) compliant 
• CE (Conformité Européene) certified 
• cUL (Canada Underwriters’ Laboratories) listed 
• C-Tick marked 
• RoHS (Restriction of Hazardous Substances) compliant 
• Meets Groups A, B, C, D, and T4A location rating requirements 
• Satisfies IEC 61800-9-2 IE2 energy efficiency requirements. 

L) EMC Filtering

Electromagnetic Compatibility (EMC) filters are used to reduce the transfer of electromagnetic noise between the mains power supply and a PowerFlex drive. This ensures that the electrical or electronic equipment being controlled by the drive is not affected by electromagnetic disturbance.

Integral EMC filtering is available on all PowerFlex 4M drives with 240V single-phase (1ø) and 480V three-phase (3ø) power ratings. These internal EMC filters provide a cost-effective means of satisfying the EN61800-3 standards. External EMC filters are also available for all PowerFlex 4M drive ratings.

On the other hand, internal EMC filters are available on select PowerFlex 4 drives with 230V single-phase (1ø) power rating. This integral EMC filtering acts as a cost-effective way of meeting EN55011, Class A, and B Electromagnetic Compatibility (EMC) requirements. External EMC filters are also available for all PowerFlex 4 drive ratings, and they ensure compliance with Class A and B EMC requirements.

M) Circuit Protection

PowerFlex 4 and PowerFlex 4M drives do not provide protection against the branch-short circuit. Instead, they are installed with either an input circuit breaker or a number of input fuses. The PowerFlex 4M and 4 AC drives are UL tested and approved for use with the following types of input fuses:

• UL – UL Class J, RK1, or T 
• IEC – Type BS88 (British Standard); 600V (550V) or equivalent 

The circuit breakers recommended for use with PowerFlex 4M and PowerFlex 4 drives are Bulletin 140M (Self-Protected combination motor controllers) or UL489 rated circuit breakers. When Bulletin 140M motor protection circuit breakers are selected, the guidelines listed below should be followed so as to meet the NEC standards for branch circuit protection. 

• You can use Bulletin 140M in single and multiple motor control applications. 
• Bulletin 140M can be used upstream from the PowerFlex 4 or 4M drive without the need for input fuses. 

Note: To prevent equipment damage and/or personal injury due to improper circuit breaker or fusing selection, ensure that you check the recommended minimum or maximum current rating values for the line fuses and circuit breakers specified for use with each PowerFlex 4 or 4M drive rating.