The 2000 series SoDARs measure vertical and horizontal wind speed, and wind direction with 10-m resolution up to 700m.

The 2000 series SoDARs are intended as high-altitude sensors. These use three parabolic dishes in three separate enclosures. The 2000 series can operate in lower power consumption mode, pulsing each antenna at different time intervals. Or, they can be configured to sample all three beams simultaneously, increasing the number of complete samples during the averaging intervals. This unit captures data in real-time. The 2000 products measure vertical and horizontal wind speed, and wind direction with 10-m resolution up to 700m. The digital facsimile offers a look at the atmospheric structure exposing inversions and other critical information. The equipment can work remotely or in a network.

Atmospheric Systems Corp.
www.minisodar.com

Windpower Engineering & Development

The DT Series Large Aperture Current Transducers combines a hall effect sensor and signal conditioner into a single package for use in dc-current applications up to 1,200 amps.

The DT Series Large Aperture Current Transducers combines a hall effect sensor and signal conditioner into a single package for use in dc-current applications up to 1,200 amps. Factory calibrated ranges simplify operation and eliminate zero and span pots. Industry standard 4 to 20 mA, 0 to 5 Vdc or 0 to 10 Vdc outputs are magnetically isolated from the input to provide maximum safety, and eliminate insertion losses. Internal power regulation delivers reliable operation and helps keep installation costs low, even in applications with unregulated power. A DIN-rail mount enclosure makes installation easy.

“DT series current transducers provide design and process engineers with a rich source of equipment information,” says Philip Gregory, President, NK Technologies. “The devices are said to be economical and reliable tools for monitoring equipment status, detecting process variations and allow taking corrective action before a failure occurs, and ensuring personnel safety.”

The ability to monitor circuit up to 1,200A makes the large aperture current transducers well suited for applications that include:

• Monitoring load and charging currents, and verifying operation, of battery banks
• Measuring traction power or auxiliary loads in transportation applications
• Monitoring dc powered motors in cranes, saws, sorters, and positioning equipment
• Measuring produced or consumed current, and detecting mechanical problems before a failure, in wind and solar applications.

Test and evaluation units are available to OEMs at no cost. The Engineering Resources section of NK Technologies website provides numerous application notes, and technology white paper on current sensing technology.

NK TECHNOLOGIES
http://www.nktechnologies.com

Windpower Engineering & Development

SKF wind turbine sensor.

Expect to find sensors in more places in part because they are getting cheaper and MEMS manufacturing techniques are making them smaller. In addition, more powerful, less expensive sensors will allow their use in more places than previously possible. Smart sensors will allow making controlbased decisions at nodes, such as turning on devices, flipping circuit breakers, or sending trend data.

Sensors come in all sizes. A laser-based wind sensor, for instance, sits in a pod and mounts to the top of a nacelle to detect wind directions 200 to 300 m ahead of the turbine.

Such sensors can signal adjustments to yaw misalignment. When a turbine runs below rated power, a 10° yaw misalignment reduces power output by about 5%. Sensors (strain gages and controls) that provide data on mass and aerodynamic imbalances allow early action to maximize power generation and avoid damage. Sensors can also tell of damage affecting the structural or aerodynamic performance of a blade, allowing early remedial action.

By identifying small degradations in performance, sensors and software in recent controls can schedule preventive maintenance and even component replacement during scheduled downtime.

Particle sensors look for debris in oil to control contamination. Most use lasers to shine a beam into an oil path to analyze the reflected light by particles. Some have algorithms that discount bubbles in the oil. A few features on one particle sensor includes monitoring contamination trends, and early warning LEDs or digital-display indicators that tell of low, medium, or high contamination levels.

Leak detectors on seals are a recent development. Onboard electronics provide some analysis and can send results to a computer or telephone. This allows remotely monitoring a seal and scheduling an exchange when necessary in a normal maintenance interval. DIN 3760 standards describe function and lifespan for such seals. The sensor-seal combination is available in many different dimensions.

Windpower Engineering & Development

The ZephIR 300 provides remote resource measurements of wind speed and direction from 10 to 200m above ground.

ZephIR 300 wind lidar, remote sensing for U.S. wind energy market, will be available in the U.S. through Campbell Scientific. The wind sensor is said to provide accurate wind data across all stages of a wind farm project. Manufactured by Zephir Ltd. of the UK, a subsidiary of renewable energy group Natural Power, the ZephIR 300 provides remote resource measurements of wind speed and direction from 10 to 200m above ground. The lidar unit can measure 50 data points every second across a full 360-degree scan providing a high sample rate advantageous in complex and fast changing air flows. Equipment of this sort can replace met towers and with several advantages. The company says lidar has demonstrated high-quality measurements across many hundreds of installations in a range of scenarios and environments. Campbell Scientific will partner with Zephir Ltd. to act as an authorized distributor for the ZephIR 300 in North America.

Ian Locker, a manager of the ZephIR business in Natural Power welcomed the announcement: “Campbell Scientific is one of the most recognized brands in the U.S. for quality data-measurement instruments and is a natural fit for ZephIR 300. Together we will meet the clear customer requirements for a high-quality lidar in the U.S. with extensive field engineering support to exceed service expectations”.

Campbell Scientific has designed and manufactured sensors, measurement and control instrumentation, and related communications peripherals for over 35 years, specializing in versatile, programmable, stand-alone systems.

Campbell Scientific Inc.
www.campbellsci.com/zephir-lidar

Windpower Engineering & Development

This nearly 1,200-page resource details the company’s family of capacitive, inductive, weld immune, special application, NAMUR, ultrasonic, and photoelectric sensors.

Pepperl+Fuchs has introduced edition 1.0 of the company’s North American Sensor Catalog and Selection Guide. This nearly 1,200-page resource details the company’s family of capacitive, inductive, weld immune, special application, NAMUR, ultrasonic, and photoelectric sensors. It also details the company’s rotary encoders, cordsets, special function devices, and accessories. Complete product specifications, benefits, and ordering information are included. More than 60 pages of the guide are dedicated to educational resource material.

Pepperl+Fuchs
http://www.pepperl-fuchs.us/usa/en/17733.htm

Windpower Engineering & Development

A hollow-shaft version of the MCD encoder makes it easy to mount these devices on shafts up to 20-mm dia.

The Magnetocode (MCD) absolute rotary encoders feature reliability, accuracy, and adaptability. Now, a new hollow-shaft version of the MCD encoder makes it easy to mount these devices on shafts up to 20-mm dia. The recent devices are available with analog (voltage/current) or digital electrical interfaces. Analog versions are a substitute for traditional potentiometers, offering superior reliability, longevity, and accuracy than units they replace. The measurement technology is based on a rotating magnet and Hall-effect sensors. Unlike traditional potentiometers, there is no contact between these components and no loss of accuracy due to wear or surface contamination. Another advantage is a flexible range-setting feature. With this, the installer can ‘teach’ the device the limits of mechanical motion that will be experienced during operations. Once these limits have been defined – which can involve multiple rotations – the device will self-calibrate so the full range of the electrical output (e.g. 0-5 volts) exactly matches the full range of mechanical movement. This improves the overall accuracy of the control system. Buttons and LEDs on the casing of the analog-output models simplify set-up. MCD encoders are well suited for applications requiring extended multi-turn capabilities (up to 8,192 revolutions). A self-powered rotation-counter (based on Wiegand wire technology) records the number of rotations – even if these occur when there is no power supplied to the sensor.

Digital outputs for MCD encoders include serial (SSI), CANopen and DeviceNet.

MCD encoders are tough. Heavy-duty enclosures protect the measurement components from mechanical loads, shock, and vibration, dust and moisture (up to IP 69K ratings). Hollow-shaft versions have a permanently lubricated steel and brass gear-set for a long, trouble-free service life.

FRABA Inc.
www.fraba.com

Windpower Engineering & Development

Premo Group
www.grupopremo.com

WPE

Windpower Engineering & Development

The magnetic-tape encoder can be installed and removed repeatedly without affecting performance, and offers wear-free speed and position feedback with a nearly unlimited service life.

Using a patent-pending HDMag MSGP sensor, the series consists of a magnetic encoder that attaches using flexible magnetic tape. The customized tape easily buckles onto the drive or generator shaft, just like a belt. With the help of a welded fastener, the tape is tightened on the shaft and can be quickly exchanged when required. A narrow read-head uses an integrated dual-sensor head mounted to a frame over the flexible tape. This takes up minimal space on the shaft and operates without interruption over the fastening gap in the tape ends, and has no effect on the encoder output signal.

To ensure uninterrupted sensing across the fastening gap, the flexible magnetic tape encoder features an integrated dual sensor head and a signal processing unit. Large permissible tolerances on axial displacement (±5 mm) and an air gap up to 3 mm ease alignment of the sensor head, and ensures reliable detection unaffected by mechanical backlash and vibrations. The encapsulated electronics built in the sensor head are protected against soiling, shocks, and vibrations. The built in FPGA-based signal processing allows for high angular resolutions, better than 0.003° respectively more than 100,000 ppr, and remains unaffected by thermal shaft expansion.

The Baumer Group
 www.baumer.com.

Windpower Engineering & Development

Each rotor blade resonates in accordance with a specific frequency curve – the blade’s fingerprint.

Hoarfrost, ice, and storms are frequent winter events in the Sternwald Forest at a thousand meters above mean sea level and on the border between Austria and the Czech Republic. Despite this, seven wind turbines faithfully work there without unnecessary downtime. Credit for this success goes to a BLADEcontrol system, built by the IGUS ITS company, Dresden. (The firm was purchased by Bosch Rexroth AG in 2009). This monitoring system detects damage and ice. Sensors, installed inside the rotor blades measure the blades’ natural resonances. “To know whether or not ice has formed on the blades, measurements must be made at the turbine,” says Dr. John Reimers, responsible for marketing and sales.
The natural resonances of the rotor blades are well suited for analysis because e blade resonates along a characteristic frequency curve. These resonances are used to create something like fingerprints during normal operations and in various malfunction modes. “Structural damage always shows itself in the lower frequency range while minor damage is seen only at the high end,” Reimers explains. Ice formation causes certain frequency peaks to shift. The rotor blade becomes heavier and thus resonates more slowly. “The system actually provides protection against false alarms.”

The ice-recognition system has to react rapidly and precisely so the turbine can be shut down quickly. “If you don’t shut down the turbine, the rotor blade can throw ice all over the place.” The system previously used in the turbines sometimes shut down too late. Conversely, rotors were often stopped at low temperatures, even though blades were ice-free. And once the turbine had stopped, a technician had to check things out before it could be restarted.
That is no longer necessary. The wind turbine can restart itself– without being inspected beforehand. This prevents unnecessary downtimes and the revenue losses they involve.
In this pilot project the wind farm also made a contribution to the great quality of the measurements made by the system. Sternwind GmbH is owned in large part by the residents of nearby communities that had decided to use power from renewable sources.

Bosch Rexroth
www.Igus-its.de

Windpower Engineering & Development

In addition to being rugged, AST pressure sensors operate over wide ranges of temperature and environments, from deserts to coastal plains.

Because of the remote location of many wind turbines, sensors serve as critical components in their operation, maintenance, and safety. Pressure sensors monitor yaw brake, lubrication oil, cooling circuit pressure, and level in gear boxes. Differential-pressure sensors monitor filter conditions. As a hydraulic filter clogs, its output signal increases, notifying the controller to replace the filter.

Wind turbines are located in deserts, coastal areas, and mountain tops, so operating temperatures can range from -50 to 60°C. In addition, wind turbines are subject to salt, mist, and fog. All can produce corrosion. Instrumentation that monitors the operating conditions for the wind turbine must survive severe conditions while providing reliability and trouble-free service.

In addition to being rugged, AST pressure sensors operate over wide ranges of temperature and environments, from deserts to coastal plains. Several sensors are said to be well suited to wind turbine applications. For example:

• AST 4000 pressure sensors offers high proof and burst ratings with excellent EMC protection
• AST5400 pressure sensors offer filter condition monitoring with linear and accurate readings.
• AST20HA pressure sensors offer pressure and temperature readings from one device, reducing process penetrations in the hydraulic system.
• AST4510 pressure sensors measure the level of oil in a reservoir while offering temperature output as an option. Maintaining and monitoring the level of oil is critical to maintain smooth supply of power from the wind turbine. For more information on the application of wind energy pressure sensors, link to: http://www.astsensors.com/application/pressure/wind-energy-pressure-sensors.php

American Sensor Technologies Inc
www.astsensors.com

Windpower Engineering & Development