NMW 2004: Motion and motor control highlights

While results and merits of last month’s National Manufacturing Week (NMW) of shows in Chicago are still being assessed, technology innovation was plainly evident in the areas of motors, drives, and motion control. Read more about highlights from these companies:

Enfield Technologies servo-pneumatic motion control ;

MDM motor management software ;

Bosch Rexroth Cartesian linear motion system ;

B&R Industrial Automation real-time Ethernet communication ; and

ThinGap Motor Technologies high-torque brushlesss servo motor .

Servo-pneumatic control system

Enfield’s advanced servo-pneumatic control system integrates a directional valve (one of 3 sizes) and a

Accurate, reliable servo-pneumatic motion control is alive and well at Enfield Technologies LLC . The company introduced its LS high-speed, advanced servo-pneumatic system for controlling position, velocity, and force (as well as pressure and flow)—in either open- or closed-loop applications. An LS System consists of a dedicated device controller and a closed-center directional valve (a 3-position, 5- port unit).

The device controller works with 4-20 mA, 0-10 V dc orwith flow capacities up to 46 SCFM and 2.5 ms valve response time—from closed-center position to fully open, in either direction. Each valve uses a directly coupled linear force (voice-coil) motor and has lapped-spool/sleeve construction for fast, smooth, stiction-free operation, explains R.Edwin Howe, president of Enfield. “This patented design provides infinitely variable and truly linear proportionality with almost zero hysteresis,” he says.

The valves can control pneumatic actuators up to 5-in. (125-mm) bore. Vincent P. McCarroll, chief engineer at Enfield, told Control Engineering that in the force-control mode, LS System has capacity to move loads up to about 1,000 lb. LS System is rated for use with clean, dry, non-lubricated air (or inert gases) from 28 in. Hg vacuum up to 150 psi (10 bar) supply.

‘1-2-3 approach’ to motor management

A “status tag” printed by the software identifies and conveys the best repair/replace options for each motor.

Motor Decisions Matter (MDM)—a national awareness campaign to promote effective motor management—introduced a software tool to help demonstrate how industrial and commercial facility managers can proactively manage their motor inventories and, at the same time, reduce motor downtime and energy usage. Objective of the evaluation tool is to quickly and simply demonstrate the financial impact of motor-related decisions such as repair, replacement, or upgrading of efficiency.

In step 1 of the “1-2-3 Approach to Motor Management Approach,” users input basic information into a spreadsheet (typically, selected motor nameplate data, hours of operation, and facility electric rates), from which the tool calculates annual motor operating costs and life-cycle financial data for making future decisions. “Users can make an informed decision on whether to repair or replace a motor before it fails , and plan accordingly,” says The Consortium for Energy Efficiency (CEE), which coordinates the MDM campaign. MDM members include motor manufacturers, electric utilities, government agencies, and trade associations.

Step 2 of the Approach applies the spreadsheet-generated results to analyze energy usage and potential savings with motors at a customer’s site. In Step 3, a proactive repair/replace decision is made based on results generated. A summary report and “status tags” are then printed for each motor (see graphic). It’s recommended that users work with a local motor representative or participating MDM sponsor to implement the software tool and develop a motor management plan specific to their needs.

“The 1-2-3 Approach is as a good starting point for small to medium-sized companies that might not have the resources to develop a motor management plan,” says the CEE. “[It also] can be used to make a persuasive business case to senior-level management.”

Cartesian linear motion system

Cartesian Motion System is available preconfigured with Cartesian robots for 1 to 3 axes.

Bosch Rexroth showcased its new Cartesian Motion System (CMS) targeted at applications with up to three motion axes. Available fully assembled or as a ready-to-assemble kit, CMS’s primary specifications include payloads up to 25 kg (55 lb), speeds up to 1 m/s (3.28 ft/s), and accelerations up to 15 m/sging time for OEMs and end-users. “CMS is simple enough to configure by customers online,” says Kevin Gingerich, marketing services manager, Linear Motion and Assembly Technologies. CMS also incorporates SERCOS, DeviceNet, and Profbus networking. Depending on the specific configuration, Cartesian Motion System offers strokes ranging up to 1.0 x 0.7 x 0.8 m for its X-, Y-, and Z-axis motion, respectively.

Ethernet Powerlink updated B&R Industrial Automation Corp . promoted its Ethernet Powerlink as a decentralized real-time communication system for high-performance automation and motion control. Ethernet Powerlink is a development of parent company, Bernecker & Rainer Industrie Elektronik GmbH of Austria. B&R’s innovation reportedly makes Ethernet deterministic for real-time industrial applications.

B&R gets around Ethernet’s limitation for guaranteed data transmission by superimposing a “time slicing” method over the carrier sense multiple access/collision detection (CSMA/CD) mechanism of Ethernet. It cuts the transmission interval into numerous slots, making a time slot available for each device linked to a network segment. “Each network node has its dedicated time window to send data,” according to B&R. This ensures that no collisions take place on the network.

“Cycle times down to 200 microseconds and jitter below 1 microsecond can be obtained,” says Markus Sandhoefner, industry segment manager for B&R Industrial Automation in the U.S. A further benefit mentioned by Sandhoefner is Powerlink’s hardware, which is based on the standard Ethernet chipset. “We wanted a commercial solution using readily available off-the-shelf products,” he adds.

Growing applications of the system range from injection molding to packaging machines. Originated in 2001, Ethernet Powerlink claims approximately 12,000 nodes installed worldwide. The open vendor and end-user association Ethernet Powerlink Standardization Group (EPSG) manages the technology.

High-power density bldc servo motor

ThinGap’s TG2300 Series bldc servo motors are thermally rated for operation at up to 100 °C.

Innovative electromotive coil design from ThinGap Motor Technologies has been applied to NEMA 23 size brushless dc (bldc) servo motors. This patented design uses multiple precision-machined copper sheets to replace conventional motors’ magnet wire and iron core. It “eliminates magnetic saturation, eddy currents, and hysteresis associated with conventional iron-core designs, improving controllability and power density,” according to the company.

ThinGap’s ultra-low-resistance coil technology minimizes I2R losses, which also contributes to high efficiency of the motor. The stator coil’s accurate wall dimension allows for a narrow air gap between the rotor and stator assemblies, enabling higher magnetic flux density for improved magnetic circuit function. This helps increase shaft power.

New TG2300 Series NEMA 23 frame bldc servo motors put this technology to work, delivering peak torque of 574 oz-in. with peak current of 70 A, for quick acceleration and deceleration of heavy loads at up to 7,200 rpm. Continuous power density is 7.5 W/oz. High peak torque can eliminate the need for gearbox reduction, in many applications, says ThinGap. “This reduces backlash, heat buildup, noise, space requirements, and cost.” Intended applications are in factory automation where precise motion control is important.

Input voltage up to 48 V dc provides further cost savings to OEMs, since servo performance is obtained at below CE- and UL-regulated safety voltage levels. Click here to download a .pdf data sheet .

Frank J. Bartos, executive editor, fbartos@reedbusiness.com

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