Online Update for October 13, 2006



October 13, 2006


Sponsored by
Rockwell Automation

Among the benefits of multi-drive systems is their ability to optimize energy use through the precise control of motors, a function that becomes increasingly important as energy supplies become more strained. According to ABB, Automation Products, Low Voltage Drives, a multi-drive is built from industrial drive modules connected to a common dc bus bar, a construction that results in such benefits as savings in cabling, reduced line currents, and simpler braking arrangements.

How Extreme are these Machines? Decide for yourself. Cast your vote! Click here. Sponsored by Control Engineering, Design News, and Rockwell Automation.

Multi-drive systems explained

Integrators, OEMs, panel builders, and end users who are interested in optimizing energy use through the precise control of motors need to consider multi-drive systems. Since drives are available in multiple- and single-drive configurations, it is useful to define the difference and highlight the benefits that the next generation of multi-drives can provide.

A multi-drive is built from industrial drive modules connected to a common dc bus bar. Key units of ABB's ACS800 multi-drive system, supply and inverter sides, are shown.

Adjustable speed drives can be used in any application where mechanical equipment is powered by motors. The drives provide extremely precise electrical motor control so motor speeds can be ramped up and down, and maintained, at required speeds. Doing so uses only the energy required, rather than using an excess of energy while a motor runs at constant (fixed) speed.

Since motors consume a majority of all energy produced, the control of motors, based on load demands, increases in importance as energy supplies become ever more strained. In addition, end users of motors can realize 25% to 70% energy savings by using motor controllers.

Single drives are highly flexible ac drives that can be customized to meet the needs of a single-motor application. These units convert ac power to dc, and then invert the dc back to an ac output to a motor. These drives cover a full range of powers and voltages, can include built-in options as standard equipment, and can be installed for most applications right out of the box.

A single rectifier

A multi-drive, on the other hand, is built from industrial drive modules that are connected to a common dc bus bar. The common bus bar is used to supply the drive modules with dc power, and each module then inverts the dc to ac and powers an individual motor. The dc power is derived from a single supply unit (rectifier) that is built into the front end of the same multi-drive configuration.

This construction simplifies the total installation and results in many benefits: savings in cabling; reduced line currents and simpler braking arrangements; energy distribution over the common dc bus bar, which can be used for motor-to-motor braking without the need for a braking chopper or a regenerative supply unit; reduced component counts; increased reliability; and space savings. There is also no need for a separate motor control center (MCC).

In general terms, multi-drives can be used whenever several drives and motors form part of a single or integrated mechanical process. The common supply of the multi-drive enables the implementation of overall safety and control functions, and permits the close coordination of individual drive motors, such as in a paper machine.

Multi-drives also can be used where the shafts of the individual drive motors are not tightly coupled; for example, in processes where each drive module can be programmed with a speed profile so that the overall use of energy is minimized.

Source: ABB, Automation Products, Low Voltage Drives, supplies a variety of energy-efficient electric drives, motors, and engineered drive products, including the new ACS800 multi-drive system. For more, visit .


No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Controller programming; Safety networks; Enclosure design; Power quality; Safety integrity levels; Increasing process efficiency
Additive manufacturing benefits; HMI and sensor tips; System integrator advice; Innovations from the industry
Robotic safety, collaboration, standards; DCS migration tips; IT/OT convergence; 2017 Control Engineering Salary and Career Survey
Featured articles highlight technologies that enable the Industrial Internet of Things, IIoT-related products and strategies to get data more easily to the user.
This article collection contains several articles on how automation and controls are helping human-machine interface (HMI) hardware and software advance.
This digital report will explore several aspects of how IIoT will transform manufacturing in the coming years.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Infrastructure for natural gas expansion; Artificial lift methods; Disruptive technology and fugitive gas emissions
Mobility as the means to offshore innovation; Preventing another Deepwater Horizon; ROVs as subsea robots; SCADA and the radio spectrum
Future of oil and gas projects; Reservoir models; The importance of SCADA to oil and gas
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
Fire & Life Safety Engineer; Technip USA Inc.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me