High-Performance Drives Provide, Flexibility in Motor Control

The Rockwell Automation PowerFlex 753 and 755 drives help companies maximize their automation investment.

As a developing region, Asia Pacific has weathered the global recession, and industries in the region are maintaining steady growth.

As such, many of the world’s top drive manufacturers, including Rockwell Automation®, have been increasing their investments in the region. In particular, China is viewed as offering strong opportunities for drives, fueled by growth in industries such as consumer goods, tobacco, construction and machine building.

According to Sam Zhang, standard drive product manager for Rockwell Automation, Greater China, the company has set a goal to become a leader in China’s low-voltage drive market by 2013. The recent introduction of the Allen-Bradley® PowerFlex® 750 Series AC Drives is helping to achieve that objective.

Drives on a Mission
The PowerFlex 750 Series offers users a range of control, communications, safety and supporting hardware options. The PowerFlex 753 provides general purpose control for applications ranging up to 350hp and 250kW while the PowerFlex 755 offers performance ranging up to 700hp and 450kW.

Zhang explains that it integrates many more new concepts in functionality, size and protection level than its predecessors. For example, drive control modes include adjustable voltage, speed, torque and position in one product to support multiple application types. Selectable, high-performance motor control algorithms with Force Technology include fl ux vector, permanent magnet motor, sensorless, and V/Hz to support induction and permanent magnet motors.

The PowerFlex 750 Series supports various network protocols to ease integration into users’ architectures. For instance, it features standard embedded Ethernet communication, enabling users to confi gure, control and collect drive data over EtherNet/IP™ networks. Other network protocols include ControlNet™, DeviceNet™, Profi bus DP, Modbus/TCP and CANopen, among others.

“A DeviceLogix™ control function,” explains Zhang, “controls outputs and manages status information locally within the drive, allowing users to operate the drive independently or complementary to supervisory control.” DeviceLogix also has a builtin capability to forecast diagnostics and follow up with information related to the life cycle of the drive and its motor, which help to prevent unplanned downtime.

Its security solutions – up to Ple/SIL 3, Cat 3 and Cat 4 – help protect the safety of the equipment and personnel. Safety options such as Safe Torque-Off and Safe Speed Monitor provide a choice for safety levels, depending on the application.

Safe Torque-Off, for example, is targeted for safety-related applications requiring removal of rotational power to the motor without removing power from the drive. It offers the benefi t of quick start-up after a demand on the safety system and helps reduce wear from repetitive start-up.

Safe Speed Monitor is used in applications that can benefi t from access to a safety zone where there is limited motion. Users can safely monitor and control the speed of their applications, allowing operators to perform process or maintenance work without stopping the machine.

The PowerFlex 750 Series features fl exibility in its hardware design. The slot-based architecture allows the drives to be built to suit application requirements, and it reduces unnecessary add-ons. Terminal blocks can be pulled apart for easy wiring. In addition, High Horse Power drives in the series are designed with a roll-in, roll-out inverter and converter for improved serviceability.

Rockwell Automation plans to further develop this series. R&D projects on a four-quadrant drive as well as new methods of increasing the power and effi ciency of the existing products are under way.

Rockwell Automation is not just a supplier of drives but also carries a range of automation products such as programmable automation controllers. “The company provides high performance and high-quality products and complete system solutions that help customers achieve sustainable, improved production, safety and enhanced competitiveness”, Zang concludes.

Staying Warm in Winter
One company that relies on the capabilities of the PowerFlex 755 drives is the Daqing Longtang Heat Supply Co., Ltd. (Longtang) in northeastern China, where the average temperatures reach -18.5°C during the coldest months – with lowest temperatures dipping to -39.2°C. The company was initially established to cover heat demands while another project to construct a power plant was under way. Later, Longtang became responsible for the peak heat source project.

Early in 2010, the company spent US$39 million to construct a 2x58MW boiler room equipped with circulating fluidised beds covering a total area of about 10 hectares and a construction area of 70,000sq. meters. Longtang Deputy General Manager Mr. Zhou explains that it is imperative for the automation products to operate in a safe, stable and reliable manner. If heat is cut off due to product quality problems, people will suffer.

For heat-supply projects in Shuangyashan, Jixi and other places, Longtang has been using automation products from Rockwell Automation. Based on the performance of the controllers and drives in use at these sites, Longtang selected Rockwell Automation products, including the PowerFlex 755 drives (700HP), for the Daqing project.

Longtang uses central heating, where water is the heat medium and flows through a thermal network to provide heating to towns, regions or individual users. The heating system that Rockwell Automation and Longtang built together uses 33 PowerFlex 755 drives.

They are employed in the grate boiler in the combustion system, coal-feeding machine, blower, fan, circulating pumps and water supply pump. The heating system also includes Allen-Bradley PLCs that automate operations.

Rockwell Automation Marketing Manager for Power Control Mr. Wang points out that system implementation and commission went smoothly on this project, and he attributes it to the drives’ design. “Rockwell Automation,” he says, “has adopted a user-friendly design of drawers in the PowerFlex 755, with each functional unit located in an individual drawer that is easily pulled in and out. This helps users to perform wire adjustments easily.”

He adds that in addition to the modular design, the drives feature a large power section and a control board with multiple power units. Also, key information is displayed on an LCD screen. If there is any failure, the drive will suggest what the failure might be and how to solve it. What’s more, thanks to powerful networking capabilities, the entire heating system can be connected to the Rockwell Automation automated monitoring system via the Internet. If a warning or failure occurs, information can be sent to the cell phone of a supervisor.

Mr. Zhou of Longtang adds that Rockwell Automation provides excellent post-sales service as well as customised training and maintenance programs. If staff encounter any problem during applications, Rockwell Automation can be reached by cell phone at any time. If the problem cannot be solved over the phone, Rockwell Automation will send its service engineers to the site to provide training, troubleshooting or emergency repairs.

Based on satisfied customers such as Longtang, Rockwell Automation is well on its way to achieving the goal of being the third largest supplier of low-voltage drives by 2013. In the 2010 fiscal year, the company achieved more than 30 percent increase in annual growth in China. With a new fiscal year, the company is on track to provide customers with cost-effective solutions and to help them improve their productivity and maximize their investment.

발문
“Based on satisfied customers such as Longtang, Rockwell Automation is well on its way to achieving the goal of being the third largest supplier of low-voltage drives by 2013.”
– Rockwell Automation

아이씨엔 매거진 2012년 06월호