A-BPowerFlex 7000 Medium Voltage AC Drive Air-Cooled (’B’ Frame)—ForGe Control

Important User Information

Read this document and the documents listed in the additional resources section about installation, configuration, and 

operation of this equipment before you install, configure, operate, or maintain this product. Users are required to familiarize

themselves with installation and wiring instructions in addition to requirements of all applicable codes, laws, and standards.

Activities including installation, adjustments, putting into service, use, assembly, disassembly, and maintenance are required to 

be carried out by suitably trained personnel in accordance with applicable code of practice.

If this equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be 

impaired.

In no event will Rockwell Automation, Inc. be responsible or liable for indirect or consequential damages resulting from the use 

or application of this equipment.

The examples and diagrams in this manual are included solely for illustrative purposes. Because of the many variables and 

requirements associated with any particular installation, Rockwell Automation, Inc. cannot assume responsibility or liability for 

actual use based on the examples and diagrams.

No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information, circuits, equipment, or software 

described in this manual.

Reproduction of the contents of this manual, in whole or in part, without written permission of Rockwell Automation, Inc., is 

prohibited.

Throughout this manual, when necessary, we use notes to make you aware of safety considerations.

About This Publication This document provides procedural information for managing daily or 

recurring tasks involving the PowerFlex® 7000 medium voltage ‘B’ frame 

drives (heatsink and heatpipe models).

Download Firmware, AOP, 

EDS, and Other Files 

Download firmware, associated files (such as AOP, EDS, and DTM), and access 

product release notes from the Product Compatibility and Download Center at 

rok.auto/pcdc.

Summary of Changes This publication contains the following new or updated information. This list 

includes substantive updates only and is not intended to reflect all changes.

Who Should Use This 

Manual

This manual is intended for use by personnel familiar with medium voltage 

and solid-state variable speed drive equipment. The manual contains material 

that enables regular operation and maintenance of the drive system.

What Is Not in This Manual This manual provides information specific to maintaining the PowerFlex 7000 

‘B’ frame drive. This document does not include topics such as:

• Physically transporting or siting the drive cabinetry

• Installing or commissioning procedures

• Spare parts lists compiled for your order. 

Rockwell Automation provides the site- and installation-specific electrical and 

design information for each drive during the order process cycle. If they are 

not available on site with the drive, contact Rockwell Automation.

If you have multiple drive types or power ranges, ensure you have the correct 

documentation for each specific PowerFlex 7000 product:

• ‘A’ frame for lower-power air-cooled, configurations (up to 

approximately 1250 hp/933 kW)

• ‘B’ frame for higher-power, air-cooled configurations (standard or 

heatpipe models)

• ‘C’ frame for all liquid-cooled configurations

PowerFlex 7000 Drive Overview

The PowerFlex™ 7000 drive is a general-purpose, standalone, medium voltage 

drive that controls speed, torque, direction, starting, and stopping of standard 

asynchronous or synchronous AC motors. This drive works on numerous 

standard and specialty applications such as fans, pumps, compressors, mixers, 

conveyors, kilns, fan-pumps, and test stands in industries such as 

petrochemical, cement, mining and metals, forest products, power generation, 

and water/waste water. 

The PowerFlex 7000 drive meets most common standards from these 

organizations: 

• National Electrical Code (NEC)

• International Electrotechnical Commission (IEC)

• National Electrical Manufacturers Association (NEMA)

• Underwriters Laboratories (UL)

• Canadian Standards Association (CSA). 

The drive is available with the world’s most common supply voltages at 

medium voltage, from 2400…6600V. The design focuses on high reliability, 

ease of use, and lower total cost of ownership.

Topology The PowerFlex 7000 drive uses a pulse width modulated (PWM) – current 

source inverter (CSI) topology. This topology applies to a wide voltage and 

power range. The power semiconductor switches used are easy-to-series for 

any medium voltage level. Semiconductor fuses are not required for the power 

structure due to the current limiting DC link inductor.

With 6500V PIV rated power semiconductor devices, the number of inverter 

components is minimal. For example, only six inverter switching devices are 

required at 2400V, 12 at 3300…4160V, and 18 at 6600V. 

The PowerFlex 7000 drive also provides inherent regenerative braking for 

applications where the load is overhauling the motor, or where high inertia 

loads are quickly slowed down. The drive uses the following:

• Symmetrical gate commutated thyristors (SGCTs) for machine converter 

switches

• SGCTs for active front-end (AFE) rectifier configurations for the line 

converter switches

• Silicon-controlled rectifiers (SCRs) for 18-pulse rectifier configurations

The PowerFlex 7000 drive provides a selectable option for enhanced torque 

control capabilities and increased dynamic control performance. This highperformance torque control (HPTC) feature delivers 100% torque at zero speed 

and provides torque control through zero speed with smooth direction 

transition.

Rectifier Designs Configurations

The PowerFlex 7000 drive offers three rectifier configurations for ‘B’ frame 

drives:

• Direct-to-Drive™ (AFE rectifier with integral line reactor and CMC)

• AFE rectifier with separate isolation transformer

• 18-pulse rectifier with separate isolation transformer

Direct-to-Drive

Direct-to-Drive technology does not require an isolation transformer or 

multiple rectifier bridges as in voltage source inverter (VSI) topologies offered 

by others. The approach is completely different. Instead of multiple 

uncontrolled rectifiers, a single AFE rectifier bridge is supplied. The rectifier 

semiconductors that are used are SGCTs. Unlike the diodes that are used in 

VSI rectifier bridges, SGCTs are turned on and off by a gating signal. A PWM 

gating algorithm controls the firing of the rectifier devices, similar to the 

control philosophy of the inverter. The gating algorithm uses a specific 

42-pulse switching pattern called selective harmonic elimination (SHE) to 

mitigate the 5th, 7th, and 11th harmonic orders

A small integral line reactor and capacitor addresses the high harmonic orders 

(13th and above) and provides virtually sinusoidal input voltage and current 

waveforms back to the distribution system. This configuration delivers 

excellent line-side harmonic and power factor performance to meet IEEE 519-

1992 requirements and other global harmonic standards in virtually all cases. 

This setup also provides a simple, robust power structure that maximizes 

uptime by minimizing the number of discrete components and the number of 

interconnections required.

A CMC mitigates the common mode voltage seen at the motor terminals, so 

standard (non-inverter duty rated) motors and motor cables can be used. This 

technology is ideal for retrofitting existing motor applications

AFE Rectifier with Separate Isolation Transformer

For applications when the line voltage is higher than the motor voltage, a 

transformer is required for voltage matching. In this case, providing an AFE 

rectifier with a separate isolation transformer is ideal (indoor and outdoor 

transformer versions are offered). The isolation transformer replaces the 

requirement for an integral line reactor and replaces the requirement for a 

CMC that is supplied in the Direct-to-Drive rectifier configuration. However, 

the AFE rectifier, its operation, and advantages are the same as the Direct-toDrive configuration.

Figure 3 - 3300/4160 AFE Rectifier with Separate Isolation Transformer

For high power constant torque applications and/or when the line voltage is 

higher than the motor voltage, a transformer is required for voltage matching 

(indoor and outdoor transformer options are available). The 18-pulse rectifier 

uses SCRs instead of the SGCTs used for an AFE rectifier. When used for high 

power constant torque applications, the 18-pulse rectifier has lower losses than 

the AFE rectifier, making 18-pulse ideal for the highest power requirements. 

The 18-pulse isolation transformer provides the required input impedance and 

addresses common mode voltage just like the separate isolation transformer 

used with the AFE rectifier. However, instead of a PWM rectifier switching 

pattern and a single rectifier bridge, the 18-pulse configuration mitigates line 

side harmonics through harmonic current cancellation in the isolation 

transformer phase shifted secondary windings. The inverter is the same 

configuration for all available rectifier options.

Figure 4 - 3300/4160V 18-pulse Rectifier with Separate Isolation Transformer

Cooling Technology These VFDs are supplied with heatsinks for most configurations and heatpipes 

for the highest-power AFE configurations. While both configurations draw 

heat away from the semiconductors, heatpipes are bigger, more efficient, and 

require larger fans and airflow. 

Information and graphics in this manual show both configurations.

Motor Compatibility The PowerFlex 7000 drive achieves near-sinusoidal current and voltage 

waveforms to the motor, resulting in no significant additional heating or 

insulation stress. Temperature rise in the motor connected to the VFD is 

typically 3 °C (5.5 °F) higher compared to across-the-line operation. Voltage 

waveform has dv/dt of less than 50 V/μs. The peak voltage across the motor 

insulation is the rated motor RMS voltage divided by 0.707. 

Reflected wave and dv/dt issues often associated with VSI drives are a nonissue with the drive. Figure 5 shows typical motor waveforms. The drive uses a 

SHE pattern in the inverter to eliminate major order harmonics, plus a small 

output capacitor (integral to the drive) to eliminate harmonics at higher 

speeds.

Standard motors are compatible without de-rating, even on retrofit 

applications. 

Motor cable distance is virtually unlimited. Rockwell Automation has tested 

this technology for controlling motors up to 15 km (9.3 mi) away from the drive.

Figure 5 - Motor Waveforms at Full Load, Full Speed

Power Component Definition and Maintenance

This section provides an overview of the control components and cabling of 

your PowerFlex® 7000 ‘B’ frame drive. This section also details a number of 

regular or recurring maintenance tasks that will keep your drive in peak 

operating condition.

Figure 20 through Figure 26 identify the control components and cabling of 

your drives. Where appropriate, separate diagrams and instructions are 

available for both the heatsink and the heatpipe ‘B’ frame models. 

For information regarding power wiring and cabling connections (as might be 

necessary for routine maintenance), see the PowerFlex 7000 ‘B’ frame 

installation manual, publication 7000-IN007.

Control Power Off Tests Perform the following checks before applying control power to the drive. 

Rockwell Automation recommends that you complete these checks in the 

sequence they are presented here.

Interlocking

When the input contactor option is purchased, a key interlock is provided to 

prevent access to the medium voltage compartments of the drive unless the 

input isolation switch is locked in the open position.

Where the input switching device is provided by others, Rockwell Automation 

will provide a key interlock on the medium voltage compartment of the drive, 

and a matching interlock for installation by others on the upstream device. The 

interlock shall be installed in a manner that ensures the power to the drive is 

off and the drive is electrically isolated whenever the key is freed.

Although key interlocks shipped with all medium voltage equipment are 

aligned in the factory, they often move out of position during shipping or are 

often misaligned when the cabinet is set down on an uneven floor. 

ATTENTION: Servicing energized industrial control equipment can be 

hazardous. Severe injury or death can result from electrical shock, 

burn, or unintended actuation of control equipment. Hazardous 

voltages can exist in the cabinet even with the circuit breaker in the 

off position. We recommend that you disconnect or lock out control 

equipment from power sources, and confirm discharge of stored 

energy in capacitors. If you must work in the vicinity of energized 

equipment, the safety-related work practices of NFPA 70E, Standard 

for Electrical Safety in the Workplace, must be followed