No matter how thoroughly an automobile is tested, there are noise and vibration problems that must be eliminated from the final design. All Big Three automakers use a scanning laser vibrometer (SLV) from Polytec PI Inc. in Auburn, Mass., to analyze the vibrations of auto parts and components.

The SLV analyzes an object to determine the sources of vibration. An SLV scan of a running engine or other structure gathers multifrequency phase and amplitude values at every point, measuring the change in the frequency of light reflected by the vibrating surface, which is directly proportional to the vibration. This technique can be used on any surface as long as it has at least a degree of opacity.

Unlike traditional vibration measurements made by a network of accelerometers attached to the mass to be tested, the SLV system requires nothing to be directly connected to the object. In addition, the network of the older method could change the mass of the test object, affect the result, and take up to several hours to install. The SLV system, however, usually provides results within a few minutes. Once its onboard electronics and software perform the necessary analysis, the operator is presented with a three-dimensional contour map that shows the vibrations for a selected frequency.

A video camera built into the unit allows the operator to superimpose a black-and-white image of the object onto the contour map. The SLV also allows velocity data to be downloaded to commercial noise-analysis software packages.

Once engineers understand the vibration, they can take the appropriate steps to fix it, such as by attaching a damping material or a stiffener. Other users of the SLV include the aerospace, appliance, and disk-drive industries.

Neural Application engineers designed the IAF controllers to be installed parallel to existing furnace control systems. The controllers typically consist of three Pentium computer processing units: the neural regulator, the supervisory system, and the file server, which facilitates communications between the first two systems. Sometimes a fourth computer is added to the IAF controller as a modem server to aid in remote communication.

The performance of this electric arc furnace was optimized by installing an intelligent-arc-furnace controller so that it will consume less electricity and fewer graphite electrodes

The supervisory system sends the set-point commands to the neural regulator, which combines those points with existing furnace conditions, such as hot points and cooling panel temperatures, to optimize the set points. The optimized points are then transmitted to electrical positioners that move and charge the electrodes in the furnace.

Companies reducing their furnaces'electrical consumption and electrode use include Bayou Steel Corp. in La Place, La.; Hokkai Steel in Sapporo, Japan; and Tianjin Pipe in Tianjin, China. Last December, an IAF was installed at the 40-ton electric arc furnace operated by Buckeye Steel Castings in Columbus, Ohio. Since then, the company has reported a 30-percent reduction in electrode use and a 6-percent drop in electric power consumption. "That puts the payback on the purchase at something around eight months," said Dennis Bockus, an electrical engineer at the Buckeye plant.

Bockus cited the additional benefit of the furnace's transformer running considerably cooler due to the newfound capability of running a longer arc.

The system helps coordinate the daily loading of millions of bushels of grain onto ships and barges for shipment worldwide. It controls the booms and spouts that carry grain from the company's 4.5 million-bushel storage facility into the holds of the huge ships that line the docks of the Mississippi River. The 24-hour operation can load a 2 million-bushel-capacity ship in about a day.

Before using radio control, workers operating the loading functions had to maneuver a heavy cable and pendant control box that weighed 25 pounds. Besides being cumbersome, the pendant was difficult to position for optimum visibility. Cable was constantly down because of damage from dockside vehicles or rips when the cable was secured to a ship that broke loose from its mooring. In addition to endangering the operator, the entire junction box would sometimes get pulled out of the boom tower.

The toggle transmitter used at the facility weighs 21/2 pounds. Operators can now position themselves at any point to see the placement of the loading spouts. The functions controlled from the transmitter include the run/stop function, the in/out motion of the boom carrying the loading spouts, the left or right and up/down position of the boom, the raising or lowering of the spout, and the 360-degree rotation of a spoon deflector at the base of the spout. Seven control systems are used, all of which can be operated at the same time without interfering with each other.

The DVR is housed in a 48- by 8.5-foot trailer for portability, eliminating the need for special permitting, or in two modules measuring 40 by 10 feet and 17 by 10 feet, mounted on a concrete pad in a permanent installation. In either case, the basic DVR consists of a customized injection transformer, power electronics (inverters) programmed with a proprietary Westinghouse software to address the application, dc capacitors for energy storage, and a solid-state bypass switch.

Westinghouse software enables the dynamic voltage restorer to inject electricity rapidly into a power line during a disturbance, preventing costly downtime for industrial processing

The first commercial installation of a DVR was made last August at the Orian Rugs plant in Anderson, S.C. The DVR proved itself at the 60-hertz, 12-kilovolt plant during a sharp voltage sag in October by preventing the 2-hour downtime normally needed for equipment cleanup and restart, according to Rick Gilbert, yarn- production and technical manager at Orian.

The DVR injection transformer was given a universal design to suit the device to a range of applications, according to Michele Peel, a spokeswoman for Westinghouse in Orlando, Fla. This flexibility is demonstrated by two DVR installations commissioned last December. One was made in Australia at Bonlac Foods Ltd.'s Stanhope dairy. This DVR will protect the flame-control valves used for powdered-milk production, a 50-hertz, 22-kilovolt application.

Florida Power Corp. also installed a DVR unit at its Econ substation in Orlando. This demonstration project supplies a 7-kilovolt feeder for commercial and residential customers, and is being used for study by the Westinghouse team.

The development of the device was co-sponsored by the Electric Power Research Institute in Palo Alto, Calif., and Duke Power in Raleigh, N.C.

According to a recent Institute of Electrical and Electronics Engineers study, more then 70 percent of widespread power-system disturbances are initiated by malfunctioning transmission-line relays. The resulting false line trips are a key factor in the outages that cascade into major blackouts, like those that have plagued Western states over the last three years. General Electric Power Systems Energy Consulting in Schenectady, N.Y., has developed a trip security system (TSS) to enhance the security of critical power lines by significantly reducing false trips.

The TSS is installed in a substation relay room, and is contained in a 24- by 32- by 90-inch steel-alloy cabinet. Its identical primary and secondary relay systems are electrically isolated from one another. Each system is built of heavy-duty solid-state relays and station-hardened digital controllers.

The trip contacts from three transmission lines are connected to the TSS, rather than the commonly used arrangement of trip contacts from two primary and backup relays connected in parallel. When a relay malfunctions, the TSS will block the false trip signal, inhibit the relay, and identify the troubled relay by activating an alarm light and informing the power system's supervisory-control and data-acquisition system.

The TSS will ignore further trip commands from that relay and allow any normal, in-service relays to trip without intervention. The transmission line will stay in service while relay technicians fix the problem, said David Bruns, an electrical engineer and senior engineer at GE Power Systems.

Bruns said that his company has delivered units to the Public Service Company of New Mexico and El Paso Electric Co.; the two utilities began installing them in April. GE has also built a 250-volt TSS to serve utilities using that voltage, most of which are in the Southwest.

To meet General Microwave's tight deadline and budgetary constraints, Compression engineers simplified production of the meter's overall seven-piece design by creating a family mold for five of the smaller parts and two individual molds for the two larger components. Designers at Compression's Indianapolis branch used Pro/ENGINEER from Parametric Technologies Corp. to generate three-dimensional solid models of the molds. IGES translated these files into Cimatron 90, the software that Compression used to generate electrode and computer numerically controlled tool paths.

Programming machine tool paths directly from the design database accelerated the fabrication of these radiation-meter parts from weeks to days

Compression engineers used these data to directly program the tool paths of the high-speed machining centers, electrical discharge machining centers, and conventional tooling equipment that machined the QC7 aluminum cores and cavities of the radiation meter in seven days. The completed tools were shipped to Shelton from Compression's Indianapolis Product Development Center, where the ejector pins and water lines were added. One hundred sets were molded in plastic within three days and shipped to the customer.

According to Russell Gulotta, senior vice president of manufacturing at General Microwave, the best turnaround time he received from 25 other mold shops was 12 weeks.

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© 1997 by The American Society of Mechanical Engineers