Users of Thomson's Motionengineering software to size a linear slide would see something like this.

The latest version of a company’s web-based linear motion-system sizing and selection software, Linear Motioneering 2.0, lets OEM and factory automation users optimize machine design and operation by walking them through an intuitive process that delivers the data necessary to make a logical system selection in minutes. The software includes Thomson products along with enhanced graphics and a streamlined user-interface. Also new to V2.0 is a sort-and-filter feature that lets users quickly and easily organize and compare all the products that fit the specific application requirements.

“With Linear Motioneering 2.0, users simply enter information on system orientation, positioning requirements, environmental conditions, load and force, and move profile requirements. The program then provides a list of recommended and linear system equipment by technology type to satisfy specific application needs,” says Jim Marek, Business Unit Manager, Thomson Systems. Outputs include 2D and 3D CAD models in multiple formats, pricing, delivery times and ordering information with a single part number.

The developer says the software is the most comprehensive system sizing and selection tool available, and offers several benefits that help users select the ideal product for their application. For instance, a motor-interface selector lets users enter motor dimensions, or major manufacturer’s motor model number, and the system configures the mating flange and coupling. The software also provides safety factors for critical system components letting users make a decision based on price and the safety margin of the selection. Users can change the move profile and calculate resulting loads and safety factors on the fly, and an environmental screen guides users to the base system selection and displays appropriate options such as material and coatings that are suitable for that environment.

The product recommended by the software, including accessories and motor mounts, is assigned a “Smart Part Number” machine builders can use to order the linear motion system with all accessories pre-mounted and ready to build into the machine. The software provides a detailed specification of the system and a summary of the loading and motion profiles, as well as an instant download of a complete 2D and 3D CAD model provided in all of the most common CAD formats. This lets the user select and specify the best linear-motion system, and then load it into his machine design in a matter of minutes. Users can also view list prices and lead-time information, and even request a quote online.

Linear Motioneering lets users configure a system based on system type or from an existing part number, thus providing three different function modes. The Sizing and Selection mode accepts information and delivers a product along with commercial and technical information. The Configure-Your-Solution mode provides the same deliverables as the Sizing and Selection mode, but is intended for those who are familiar with Thomson products and want to quickly configure a part number. The Lookup by Part Number module is a way for repeat customers to confirm current pricing and part number configuration.

 Thomson Industries
www.thomsonlinear.com

Windpower Engineering & Development

Wind turbine motor -Bonfiglioli

Hydraulic pitch controls would use servovalves along with microprocessor-based electronics and one of several network connections, such as CANopen, Profibus, or Ethernet fieldbus interfaces. These allow digital communication for improved performance, enhanced remote diagnostics, and greater process control.

A hydraulic pitch control could also include software, actuators, and pumps along with hoses, reservoirs, and brakes for precise control of each blade’s position. Actuators with digital servovalves allow changing pitch angles with a resolution of less than 1° at a response time of less than 100 ms. A fail-safe system moves the blades to a safety position in case of a fault. Temperatures in the hub where a lot of pitch equipment is mounted ranges from -30 to 70°C.

Recent CANbus compatible valve controllers operating under the CANopen protocol have the bandwidth to accommodate almost any practical load of control signals plus inputs from sensors that monitor valve and actuator performance. By identifying small degradations in performance, sensors and software in modern systems can schedule preventive maintenance and even component replacement during scheduled downtime. Electric pitch actuators often consist of a gearbox and either an ac or dc motor. Backup systems often give designers the choice of lead acid, or lithium ion batteries, or capacitors.

Pitch controls provide other possibilities with inputs from load sensors molded into the blades. For instance, load sensing would allow adjusting the pitch of each blade as needed for best rotor loading and to avoid overloads.

Yaw drives are generally electric motors mounted on a gear-reduction set and equipped with an electric release, spring-activated brake. One 2.3- MW turbine uses about eight motors to control yaw.

Windpower Engineering & Development

Motors and drives 

Inverters The output from a generator has three electrical characteristics: voltage, current, and frequency. Because wind speed varies, a wind-driven generator would produce these at variable rates as well. Hence, the inverter’s job is to steady two of the characteristics, and let only one of them vary. These electrical devices turn the variable current or voltage coming out of a generator into steady voltage and frequency that can charge a battery or contribute to power to a grid. Transformers These allow raising or lowering voltage in ac transmission lines.

Transformers for wind turbine generators are switched with solid-state controls to limit inrush current. While potentially aiding initial energization, these electronic controls also contribute damaging harmonic voltages which can lead to overheating.

Standard voltage alternates at 60 Hz. When the transformer frequency differs by even 0.2 Hz, voltage peaks from different sources do not line up and do not produce the required amplification that would come from in-synch frequencies. The transformer tries to pass this frequency through the circuit, thereby causing extra loading.

To handle potentially hazardous heat, one transformer manufacturer winds coils on a cruciformmitered core. Its circular windings evenly spread radial and axial forces over their circumference and coolantflow ducts eliminate hot spots that lead to premature breakdown and ultimately failure. Transformers for wind turbines are usually designed so their voltage exactly matches the wind turbine’s output voltage. Generator output current is monitored at millisecond intervals. Operational limits allow up to 5% over-current for 10s before controls take a generator off the system. Because transformers used with wind turbine generators are intended to match generator output without overload sizing, the generator must function without extra capacity.

Circuit breaker These devices allow working on high-voltage equipment by electrically isolating it when necessary. Recent compact circuit breakers let panel builders place voltage transformers in the top compartment of the switchgear, which reduces the switchgear footprint from that needed by older equipment. In one version,Ppole units are encapsulated to protect high-voltage components from the environment, and motorized levering allows remotely racking (installing or removing) the breaker for enhanced safety. Recent designs also eliminate SF6, a potentially hazardous gas used as an insulator instead of air inside some switchgear.

Remote racking allows insert and remove breakers while standing outside the arc-flash boundary (high voltage can jump an air gap and produce a fatal shock) and increase the distance between the operator and the front of the switchgear lineup during racking operations.

What’s more, breakers engineered for wind applications can be customized. Such accessories facilitate and simplify integrating the breaker into switchgear. A few custom features includeSself-aligning and coupling primary and secondary disconnecting devices, and rrip-free interlocks prevent moving a closed breaker into and out of the connect position. Also Coding pins ensure that only breakers of the correct rating can be inserted into the enclosure andDdistinct latch positions tell the technician whether the breaker is disconnected, in test, or working.

Windpower Engineering & Development

Guodian United Power Technology Co. Ltd. has successfully completed the grid connection for its first 3-MW wind turbine, which uses Moog’s AC servo motion-controlled pitch system.

This is the first time Moog has supplied its AC servo motion-control pitch to a Chinese wind turbine manufacturer for a project in China. The new anti-corrosion and moisture-proof design protects its components against harsh weather. GUP’s 3 MW turbine system also incorporates Moog’s latest pitch motor. This synchronous servo unit provides motion-control redundancy during an emergency and is highly reliable and precise. Moog’s pitch motor, when paired with its pitch servo drive for wind turbines, meets stringent technical specifications for all types of wind energy applications. And the adoption of ultra capacitors in place of widely-used lead-acid batteries as backup power offers enhanced system reliability and reduced maintenance costs.

“Harsh operating environments have raised the requirements demanded of pitch motors for wind turbines. Consequently, AC servo motor technology is the choice for future developments. Additionally, users will save on operation and maintenance costs,” added Rasmussen. The pitch control system is a motion controller that ensures effective use of wind energy and protection for large mainstream wind turbines. Company drives operate under extreme temperature conditions within the switch cabinets of wind turbine rotor hubs. This system withstands high mechanical loads, while improving the operating efficiency of wind turbines.

Improving grid connection capability is one of the technical challenges Chinese wind turbine OEMs must address while Low Voltage Ride Through capability is critical for minimizing turbine downtime during unstable grid power conditions. In June 2010, Moog and GUP completed China’s first LVRT wind turbine test. Moog’s new pitch system tailored for GUP’s first 3MW wind turbine also has this feature and maximizes safety performance.

Guodian United Power Technology Co., Ltd.
http://www.gdupc.com.cn/

Windpower Engineering & Development

Hydraulic pitch controls would use servovalves along with microprocessor-based electronics and one of several network connections, such as CANopen, Profibus, or Ethernet fieldbus interfaces. These allow digital communication for improved performance, enhanced remote diagnostics, and greater process control.

A hydraulic pitch control could also include software, actuators, and pumps along with hoses, reservoirs, and brakes for precise control of each blade’s position. Actuators with digital servovalves allow changing pitch angles with a resolution of less than 1° at a response time of less than 100 ms. A fail-safe system moves the blades to a safety position in case of a fault. Temperatures in the hub where a lot of pitch equipment is mounted ranges from -30 to 70°C.

The latest generation of CANbus compatible valve controllers operating under the CANopen protocol have the bandwidth to accommodate almost any practical load of control signals plus inputs from sensors that monitor valve and actuator performance. By identifying small degradations in performance, sensors and software in today’s systems can schedule preventive maintenance and even component replacement during scheduled downtime.

Electric pitch actuators often consist of a gearbox and either an ac or dc motor. Backup systems often give designers the choice of lead acid, or lithium ion batteries, or capacitors.

Pitch controls provide other possibilities with inputs from load sensors molded into the blades. For instance, load sensing would allow adjusting the pitch of each blade as needed for best rotor loading and to avoid overloads.

Yaw drives are generally electric motors mounted on a gear-reduction set and equipped with an electric release, spring-activated brake. One 2.3-MW turbine uses about eight motors to control yaw.

Windpower Engineering & Development

One trend in wind motors and drives is an increasing demand to refine overall turbine design for lower cost and higher availability. Also, instead of buying the gearbox and motor separately from different manufacturers, some companies offer them packaged together. Lastly, requirements for pitch control are increasing in larger, more powerful turbines.

Pitch control is a key safety system in turbines. Ray Opie, senior project engineer at Moog, says their customers are looking to refine over all turbine design for optimized cost and availability. “They want to increase the hours of the day the turbine runs, thereby producing more power and achieving better cost-effectiveness,” he says. “Also, lower costs are making things thinner and more slender, which means the pitch system is more dynamic.”

This leads to another trend concerning increased requirements for pitch-system performance. “This seems to be across the board,” Opie says. “Blade sensing systems at the root of each blade help increase pitch control and allow using motors and drives to turn the blades, improving reliability and safety.” These load sensors molded into the blades allow adjusting pitch as needed for best rotor loading and to avoid overloads.

Opie says the industry is also starting to look at the methodology used elsewhere with reliability assistance. Reliability is especially important in wind turbines. “As with aircrafts, things can’t go wrong,” he says. “They must always do what they need to do. There are many tools from other industries to determine reliability in wind.” Electric pitch actuators often consist of a gearbox and either an ac or dc motor. To further optimize reliability, Moog offers the gearbox and motor as a package, instead of having to purchase them separately from different manufacturers.

Also, as in most industries, the motors and drives industry is looking for ways to reduce maintenance and replacements. Network connections in hydraulic pitch controls have the bandwidth to accommodate almost any practical level of control signals, plus inputs from sensors that monitor valve and actuator performance. By identifying small degradations in performance, sensors and software in today’s systems can schedule preventive maintenance and even component replacement during scheduled downtime.

Furthermore, Greg Schulte, president of Bonfiglioli USA, says industry attention is on nacelle weight reduction, reduced maintenance, and faster installation. “This has inspired our company to design a compact line of multistage, planetary gear motors for yaw control that comprise all these features,” he says. The motors are more compact, 8% lighter, and have 11% fewer parts, which simplifies maintenance with longer service periods. Opie says Moog is also focusing on component enhancements to offer the simplest, most reliable product.

WPE

Windpower Engineering & Development

A case study shows how condition-monitoring data and engineering analysis can identify the root cause of trouble in wind-turbine drivetrains, and then give design teams information to solve the problems.

Maintaining profitability is one of the biggest challenges facing offshore wind-farm operators and owners. Innovative technology and logistics mean reliability issues and traditional reactive-maintenance practises lessen viability of equipment mounted offshore.

To meet these challenges, wind-farm owners and operators are turning to “asset management” companies along with operations-and-maintenance (O&M) suppliers to reduce the cost of running the turbine fleet. As with any fledgling industry, offshore wind is bound to suffer from teething problems. Drivetrain failures are responsible for a significant amount of turbine downtime, particularly in the gearbox and main bearings.

Why repairs fail

There are many reasons these major components suffer. Most of their performance shortcomings stem from extreme weather conditions, manufacturing errors, and sometimes fundamental design flaws. Surface fixes, such as bearing or gearbox replacements, often prove to be short-term fixes and fail to find a root cause. Superficial repairs lead to repeat failures and additional cost.

The tech records a few maintenance figures in a nacelle. The size of the gearbox shows that almost any repair to it will require heavy-duty labor.

Mitigating such risk requires an in-depth understanding of the complex drivetrain system and environmental interactions, something which only experienced wind-energy providers and technical experts can provide. Drivetrain assessments, component-life predictions, and end-of-warranty inspections form part of an O&M program that can reduce cost and increase reliability.

A good example of how these services can improve turbine reliability and safeguard future wind farm profitability is a recent project conducted by colleagues at an offshore wind farm. The project set out to identify the cause of an unusual number of identical failures in the turbine fleet. The operator also wanted to understand the nature of the vibration characteristics uncovered by their condition-monitoring data, and whether those signatures were indicative of a wider reliability issue.

A failure distribution analysis found that 80% of the particular failures were due to bearings, and nearly 10% due to gears. The bearing-failure ratio was much higher than other farms in the fleet, especially for the high-speed shaft bearing which was a problem for the turbines in that series. The engineering analysis team had to establish the root cause of the high-speed shaft bearing failure.

An assessment of vibration data showed that the high-speed gear mesh’s 3rd harmonic and oil pump’s 6th harmonic had high amplitudes near the machine’s rated speed and power.

When the machine speed decreased, these vibration amplitudes reduced markedly, but the high-speed gear mesh 4th harmonic grew in magnitude. Field data showed that at rated speed and power the two vibration sources (high-speed gear mesh and oil pump) where contributing 40% of the RMS vibration level of the gearbox. Assessing data from other turbines in the fleet showed the vibration issue in all gearboxes of the same make and pointed to a serial design problem.

To carry the investigation further, the team built a simulation model of the gearbox in RomaxWIND software to predict the structural vibration response from the gear transmission error and its multiple harmonics. The software is a simulation tool with capability to model an entire gearbox (gears, carriers, bearings, lubricant, and housing) and predict dynamic behaviour under particular operating conditions –certain torques and speeds. It is applied to wind farm, drivetrain-issues in combination with practical engineering design and field work.

LEFT: A gearbox simulation showed several modes that will be excited near 1,600 rpm. The image shows one example, a bending mode of the high-speed shaft. The model can be used for gear-tooth microgeometry optimization, one way to reduce the vibration level. CENTER: Data for the charts came from a different wind farm than the one in the case history. The top pie charts shows turbines there have trouble about 59% of the time because of gearbox failure, and those most often because of bearings, and that most bearing failures occur on the high-speed shaft. RIGHT: A wind turbine gear box has been modeled in Romax Wind, modeling and simulation software for wind turbine drive trains and pitch and yaw systems. A transparent housing shows two planetary stages and their arrangements.The high-speed output shaft appears to the lower left with the output torque designated as a red ring.

The vibration spectra plots vibration amplitude versus frequency for two shaft speeds. At 1,698 rpm on the output shaft, the oil pump’s 6th harmonic and the high-speed shaft’s 3rd harmonic dominate. Dropping the shaft speed to 1,296 rpm also drops amplitudes of the two components while the 4th harmonic on the high speed shaft dominates. This indicates something amiss with the high-speed shaft.

The software’s dynamic analysis demonstrated that subsystem resonance at rated condition was the likely cause. The Waterfall graph shows a predicted housing response for the first three harmonics of the high-speed gear mesh. The resonant behavior of the system with the 3rd harmonic from 1,600 to 2,000 rpm is also evident. Correlating to the vibration characteristics from field data helps then to use the model to understand the source. In this case, many local structural modes are excited by the HS gear and oil pump higher harmonics. The illustration Bending Mode shows an example bending mode that will respond to the excitation.

The analysis uncovered several issues contributing to the poor bearing reliability, one of which is a serial issue of resonance of gear excitation frequencies with the structure. By simulation and field work, the analysis team demonstrated that the gearbox had not been designed for good vibration characteristics at operating torque and speeds. In addition, the technical team was able to explain how design improvements could overcome these issues.

For a gearbox retrofit, it is not practical to change the structure and shift the resonances. Hence, practical engineering solutions include investigating the surface waviness of the oil-pump gear from manufacturing processes to ensure it is not related to the 6th harmonic, changing the number of gear teeth on the pump, or improving the microgeometry design.

For the high-speed gear, a good avenue for improvement would be microgeometry optimization to reduce source excitation; the third harmonic of the gear transmission error. Microgeometry optimization could include parameters such as tip relief, root relief, and involute crowning and would need to be engineered so modifications do not reduce gear durability.

By redesigning the component, the turbines would be able to run more effectively. Of course, gearbox rebuilds must be kept within design and cost constraints and they certainly should not go back to the field with the same problems.

Understanding flaws

The analysis team showed that by understanding faults and the ability to predict the lifespan of components through simulation, wind-farm operators can greatly improve their knowledge and ability to schedule maintenance for their fleet of wind turbines. Much of Romax’s field engineering focuses on this issue because a reasonable bottom line for the fleet depends on improving reliability and controlling costs.

A proactive approach to turbine fleet management can have a significant impact on the running costs and fleet uptime. The ability to feedback potential design issues through the manufacturing cycle also significantly aids in the design of new machines and helps ensure the next generation of turbines is installed without the problems of the past.

Housing response to high speed gear vibration: High-speed shaft speeds plot on the X axis (rated speed is approximately 1,600 rpm for this shaft). Vibration amplitude plots on the Z axis, from the gearbox housing near the high-speed shaft. And response frequency plots on the Y axis. It’s the frequency of the actual vibration of each harmonic at a certain shaft speed (X axis speed). As the gearbox speeds up, vibration at the 3rd harmonic grows to a resonance near 1,600 rpm and then falls away again as the machine runs faster. The high-speed gear is the largest contributor to vibration.

WPE

Windpower Engineering & Development

Recent variable frequency pump and fan drives from ABB save energy, compared to other flow-control methods such as throttling. Additional efficiencies come from monitoring, analyzing, and optimizing system operation

The ACS310 is intended to install and get up and running fast, particularly when it is to drive pumps and fans. The addition to ABB’s ac drive family ranges from 200 to 480 Vac, 0.5 to 30 hp (0.37 kW to 22 kW). The drive has features for pumps and fans– complemented with advanced, energy efficiency.
“This compact, easy-to-use drive offers the most advanced pump-and-fan features and pump-protection functions,” says Greg Semrow, ABB LV Drives product manager.
The ACS310 comes standard with two independent, built-in PID controllers for regulating pressure, flow, or other quantities. The PID control is widely used in automation and process industries. Applications include motor-speed control in various conveyors, pressure and temperature controls in ventilation systems, flow control in pumping systems, and different kinds of level-control applications. The second PID controller can eliminate need for an external PID controller, help improve process quality, and save energy and up-front costs.
Pump and fan control (PFC) switches auxiliary pumps on-and-off as required as capacity changes. An Auto-change function (when enabled and with the appropriate switchgear) alternates a pair of pumps on the same line to equalize their duty times. With the PFC feature, one drive controls several pumps or fans in parallel. Auto-change periodically increments the position of each motor in the rotation – that is, a speed-regulated motor becomes the last auxiliary motor, and the first auxiliary motor becomes the speed-regulated motor. An interlock function lets the drive detect when any of the pumps are unavailable, switched off for maintenance, for example. In which case, it starts the next available pump.
Soft pump and fan control (SPFC) is used for pump and fan alternations in which lower pressure peaks are required when a new auxiliary motor is connected online. SPFC is an easy way to implement soft starts for direct on line (auxiliary) motors. The difference between traditional PFC and SPFC is the way SPFC connects auxiliary motors online – with a flying start, while the motor is still coasting. Thus, in some cases, SPFC makes it possible to soften the start-up current while bringing auxiliary motors online. SPFC control requires the Auto-change function and appropriate switchgear.
The ACS310 comes standard with advanced pump protection functions such as Pipe Fill, a pre-programmed control method to start a pump system and fill pipelines. Pipes fill smoothly with fluid before activating closed-loop control. Pump Cleaning executes pre-programmed cleaning sequence for pumps at drive start or when required with some other source, such as digital inputs or current/torque limits. A Pump Cavitation function allows monitoring pump inlet and outlet pressures through external sensors. And a Pump Protection function can generate an alarm, provide protection during the event, or trip the drive on a fault.
The drives also have built-in energy efficiency counters that calculate the energy savings of the application in kWh and MWh — the cost of the energy saved in a local currency. The ACS310 includes other efficiency features, such as a built-in statistical tool, Load Analyzer, which saves process data, (current and torque values for instance) that can be used to analyze the pump’s energy efficiency. An energy optimizer optimizes flux so that the total energy consumption and motor-noise level are reduced when the drive operates below the nominal load. The total efficiency of the drive system can be improved up to 10%, depending on load torque and speed.

ABB

www.abb.com

Windpower Engineering & Development

The design features several advantages, such as a capability to withstand high mechanical loads in the rotating hub. An external connection is facilitated by means of an integrated diode for EPU and dc link circuit decoupling. No need for shielded cables for the EPU because its connection is included in the EMC concept. Accurate EPU voltage measurements reduce the number of additional components in the switchgear cabinet, thus reducing installation time and increasing reliability. An integrated acceleration sensor supplies information on rotor speed, rotor position, and vibrations. This data can be used for condition monitoring equipment. An inherently earth-fault proof brake driver allows regulating holding brakes to EPU voltage level, thus reducing the number of relevant switching devices in the switchgear cabinet. The motor software also supports control of synchronous, asynchronous, or dc motors.

Lastly, the PITCHmaster II was optimized to increase its reliable operation in harsh environments. This reduces the number of maintenance intervals which leads to higher wind turbine availability.

Windpower Engineering & Development

Windpower Engineering & Development