Articles About gearbox efficiency
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Thrust cone bearings are an elegant option to handle the axial forces generated by the torque transmission in helical-toothed gear stages. They have proven as an efficient and reliable bearing concept for integrally geared compressors but are nearly unknown in other fields of gearbox engineering. The presented investigations consider three aspects which appear relevant to extend the field of possible applications for thrust cones towards gearboxes constructed with roller bearings.
In the general context of the reduction of energy consumption and polluting emissions, gearbox efficiency has become a major issue.
Can direct drive technology improve your bottom line? Manufacturers relying upon drive systems in their production process have long sought ways to improve gearbox efficiency. While a gearbox-driven system has been the mainstay for manufacturers, it has also been, among other things, the source of frequent breakdowns, expensive line stoppages and increasingly costly maintenance.
In recent years the estimation of gearbox power loss is attracting more interest â” especially in the wind turbine and automotive gearbox industry â” but also in industrial gearboxes where heat dissipation is a consideration as well. As new transmissions concepts are being researched to meet both ecological and commercial demands, a quick and reliable estimation of overall efficiency becomes inevitable in designing the optimal gearbox.
The improvement of the energy efficiency of industrial gear motors and gearboxes is a common problem for many gear unit manufacturers and end-users. As is typical of other mechanical components, the radial lip seals used in such units generate friction and heat, thus contributing to energy losses of mechanical systems. There exist today simulation tools that are already helping improve the efficiency of mechanical systems â” but accurate models for seal frictional losses need to be developed. In this paper SKF presents an engineering model for radial lip seal friction based on a physical approach.
As gear efficiency is improved in small steps, it is important to be able to distinguish actual improvements from scatter that can occur while testing. An FZG back-to-back gear test rig was used to investigate how the assembly and re-assembly of the same test setup affects the measurements. A spread in torque loss between one assembly and another of the same test setup were observed. Rig conditions also affected the spread in input torque. With knowledge of how the spread in torque loss varies due to assembly, test results could be distinguished between changes due to assembly and actual differences between tests.
The mechanical components of your drive system play a major role in overall system efficiency. Don't cut corners.
Gearing is an essential component in conveyors. The material handling industry appears divided between those who favor high-end three-stage helical bevel gearboxes and those who rely on less expensive worm gearing. But thereâ™s an often over-looked alternative, the two-stage helical bevel gearbox.
In keeping with a national push to bring greater energy efficiency to wastewater treatment plants, a Pennsylvania facility used data loggers to analyze motor utilization, a first step toward cutting energy costs and meeting environmental rules.
motors with premium efficiency counterparts presents businesses with a significant opportunity to reduce operating costs. A comparison between premium and standard efficiency motors from 0.25 to 10 horsepower is conducted; comparisons of full-load efficiencies are shown, and estimated payback periods are calculated. Methods for calculating the yearly kilowatt-hour consumption and yearly cost savings of premium efficiency motors for this horsepower range are also given. The cost advantages of premium efficiency motors are summarized, and relevant examples of real world cost savings are shown.
Our politicians in Washington continue dithering over the Obama administration energy bill aimed at developing alternative, green sources of energy production. As a result, when this country will have a viable energy program in place is anyoneâ™s guess, given the usual D.C. gridlock. And yet, Americans can take more than cold comfort in the fact that at least some government agenciesâ”U.S. Department of Energy (DOE)â”and the private sectorâ”some major manufacturersâ”are doing more than their share of work in trying to harness our existing, fossil-based energy sources in such a way that they are used to their best efficiencies.
Much of the industrial energy being consumed by systems is wasted through inefficiency. For this article, a system will be defined as the following components working together: electrical input power, variable frequency drives, induction motors, gearboxes and transmission elements (chains, belts, etc.).
Options abound for increased efficiency in lubrication.
Motion systems bring award-winning and energy-optimizing âœSmart Houseâ to life.
Next time you are strolling across a manufacturing plant, check out the hardware on the ground. Shop floors are nothing but cables plugged into machines, cables plugged into computers, cables plugged into other cables...
Managing Editor Randy Stott takes a look at what is really stopping us from pursuing energy efficiency in engineering.
It is a simple fact: better lubrication can lead to dramatic energy savings and an improved bottom line. This ought to interest any plant manager who is looking for ways to reduce operating costs, and it is especially significant at a time when stricter government regulations are in direct contradiction to reducing costs. Lubrication reliability is the solution; this article will describe how manufacturing plants can use âœlubrication reliability best-practicesâ to reduce their energy consumption, emissions and operating costs—all at the same time.
Synchronous motors controlled by variable speed drives are bringing higher efficiencies to industrial applications.
The Bearing Specialists Association explains the role of bearings in ensuring the efficient operation of machinery.
Perhaps you donâ™t need convincing that sustainability is the wave of the future. But where to start? Resources of all typesâ”from websites to trade shows to white papersâ”are waiting to help green your operation. Most areas are home to regional business alliances devoted to helping local manufacturing outlets contribute in an environmentally sound manner. Here are a few go-to resources for going green.
If torque conversion with high gear ratio, compact installation space and 90-degree axis-crossing angle is needed, often worm gears are used. Due to their high power density and sliding speeds within the tooth contact, frictional heat and thermal stresses are higher compared to helical, bevel and hypoid gears, and thus the thermal load capacity of worm gears is lower.
Research has shown that the phasing of the planets in an epicyclic system can have a significant impact on the dynamic characteristics of the gearbox.
Bearing subsystem life and reliability explained.
The presented method offers a possibility or the quantitative evaluation of the operational behavior of integrated transmission systems.
Gearbox Modifications Protect 1.2 Million Acres of Arkansas Farmland
Cutting-Edge gearbox design software.
CEE/NEMA repair-or-replace campaign saves energy, dollars and downtime.
Calendar of early 2022 events
As concerns surrounding the environmental impact of fossil fuels continue to grow, so does the need to produce vehicles with higher overall efficiency. The importance of enhanced vehicles has spurred drivetrain component manufacturers to study every aspect of efficiency loss in their products. The gearbox is a key contributor to the overall drivetrain efficiency.
In looking for potential opportunities to reduce energy consumption via the drive system, a number of areas should be considered.
The use of motor structures which can concentrate magnetic flux allows ferrite PM motors to achieve performance and power densities that approach those of PM motors using rare earth magnets, but without the cost penalties and supply source concerns of rare earth magnets.
This three-part series on motor management best practices focuses on the importance of instituting a motor management plan as a necessity in effectively administering the electric motors in a facility. The goal of a motor management plan is to take advantage of opportunities for energy savings and increased productivity using energy efficient, reliable motors such as NEMA Premium efficiency motors, herein referred to as âœpremium efficiencyâ motors.
U.S. manufacturers, such as food processors, face an unprecedented competitive environment and must look for ways to be profitable without negatively affecting the quality of finished products.
Energy costs and downtime can be greatly reduced by instituting a motor management plan. Part II of this three-part series specifically addresses the establishment of a motor failure policy and the development of purchasing specifications. Part I addressed the general aspects of a motor management plan, including the first steps of creating a motor inventory and guidelines for motor repair and replacement. Part III will examine motor repair specifications as well as preventive and predictive maintenance.
Reducing losses and increasing profits by instituting a motor management plan is what this series of articles is all about. Here in Part I, we discuss how to create a motor inventory and establish repair-or-replace motor guidelines. Subsequent topics in this three-part series will address (Part II) motor failure policies and purchasing specifications, and (Part III) repair specifications and preventive and predictive maintenance, respectively.
Energyâ™s endless energy efficiency game of whack-a-mole, motors have historically always been one of the go-to moles. Theyâ™ve been in the spotlight since 1992. Over the past few decades, repeated efficiency laws have seen motor efficiency get whacked into tighter and tighter shape.
Increasing pressure on many fronts is compelling mine operators to thoroughly examine every phase of their operations. Fluctuating demand that whipsaws mineral prices, government-imposed environmental regulations and rising operating costs related to maintenance downtime all pose serious challenges for the mining sector. Add pressure from customers and stakeholders for more sustainable operations as well as union demands for higher wages, and you have a scenario that requires mine operators to exercise every possible option to achieve more efficient operations.
The Role of Coupling Technology in Current Developments in Industry
How to Ensure Reliable Performance, Increased Efficiency and Lowest Total Cost of Ownership.
Conservation through lighting alterations using different bulbs, ballasts and light sources is well understood and easy to achieve. The use of improved efficiency three phase induction motors has not been as accepted. There are a number of reasons why conservation efforts with motors have not been as popular.
The secondhand on the Doomsday dial ominously spins around the face, slowly but ever so surely inching the motor industry towards its inevitable terminus:
Over the past few decades, energy efficiency in motors has become an ever-increasing concern for OEMs and manufacturers alike. With multiple energy bills mandating higher efficiency across ever-broader spectrums of motors, including the most recent Small Motor Rule by the Department of Energy, efficiency has become an essential consideration when choosing a new motor.
Why gearboxes rate as one of the highest-type maintenance components.
Electric motor-driven systems are the single largest enduser of electricity, accounting for over 40% of global consumption according to the International Energy Agency.
Varying installation requirements for worm gears, as, for example, when used in modular gear systems, can necessitate grease lubrication - especially when adequate sealing for oil lubrication would be too complex. Such worm gears are being increasingly used in outside applications such as solar power plants and slew drives. While knowledge about the operating conditions is often appropriate, the basic understanding for load capacity and efficiency under grease lubrication is quite poor. Investigations done at FZG and sponsored by FVA/AiF are shown here to give an impression of the basic factors of load capacity and efficiency. The results of the investigation indicate a satisfying quality of calculations on heat, load capacity and efficiency based on characteristic parameters of the base oil with only slight modifications to the methodology known from DIN 3996 or ISO TR 14521.
This product focus highlights the latest technology in electric motors.
A Practical Comparison of Planetary and Orbitless Gear-Heads.
According to the Department of Energy (DOE), more than half of all electrical energy consumed in the U.S. is used by electric motors. To address this, several years ago, the DOE conducted a technical study as to what could be done to raise the efficiency levels of âœsmallâ motors. After years of study and litigation, the Small Motor Rule (SMR) was passed that covers two-digit NEMA frame single- and three-phase ¼ through 3 horsepower motors in open enclosures.
This paper presents a physically grounded calculation method to determine the efficiency of worm gear drives. This computation is based on the Institute of Machine Elements, Gears, and Transmissions (MEGT) tribological simulation, which can determine the local tooth friction coefficients (Ref. 1). With this knowledge other power losses such as the bearings, oil churnings and seals power losses can also be calculated.
Copper's continuing role in energy-efficient motor development.
In this work a physically based method for the tribological investigation of worm gears is presented.
A good deal of confusion exists regarding the factors that determine an industrial electric bill. The following information is presented to help sort out the various items on which billing is based, and to offer suggestions on measures to help control and reduce electric utility bills.
PTE Examines Gearmotor and Gear Drive Technology
The growth of worldwide energy consumption and emerging industrial markets demands an increase of renewable energy shares. The price pressure coming from coal, oil, nuclear and natural gas energy - combined with enormous worldwide production capacities for components of wind turbines - make wind energy a highly competitive market. The testing and validation of gearboxes within the test rig and the turbine environment attract a strong focus to the needs of the industry. The following contribution sums up the typical process requirements and provides examples for successful system and component verifications based on field measurements.
The chemical and physical properties of gear oils may change, depending - more or less - upon their formulation and the environmental conditions under which they are used. This is why - after three years of use in a wind turbine - a gear oil was examined to determine if indeed changes were evident and if the protection of the gears and rolling bearings still met the same requirements as would be expected of fresh oil. Our findings revealed that the existing gear oil - as well as its ability to protect the gears and rolling bearings - had degraded very little compared to fresh oil.
A critical problem for wind turbine gearboxes is failure of rolling element bearings where axial cracks form on the inner rings. This article presents field experience from operating wind turbines that compares the performance of through-hardened and carburized materials. It reveals that through-hardened bearings develop WEA/WECs and fail with axial cracks, whereas carburized bearings do not. The field experience further shows that a carburized bearing with a core having low carbon content, high nickel content, greater compressive residual stresses, and a higher amount of retained austenite provides higher fracture resistance and makes carburized bearings more durable than through-hardened bearings in the wind turbine environment.
In most applications, gearbox reliability is critical to the productivity of the overall plant operation. So it follows that when industry is looking at the best ways to increase efficiency, reduce downtime, and increase profitability, gearbox performance and reliability are key factors. Designing for repair, and writing effective repair procedures, can speed the service time, and provide a quality refurbishment. The best practices listed in this article are proven, effective methods used to install and remove bearings, seals, gears, couplings and shafts within a gearbox.
Wind turbine gearboxes are subjected to a wide variety of operating conditions, some of which may push the bearings beyond their limits. Damage may be done to the bearings, resulting in a specific premature failure mode known as white etching cracks (WEC), sometimes called brittle, short-life, early, abnormal or white structured flaking (WSF). Measures to make the bearings more robust in these operating conditions are discussed in this article.
This paper presents an evaluation of measurements being taken on a 750 kW wind turbine gearbox being tested by the National Renewable Energy Laboratory (NREL). High-speed stage gears and bearings have been identified as critical components of the gearbox; during gearbox testing, these components were instrumented and tests were developed to evaluate loads on high-speed tapered roller bearings (TRBs). In this paper an advanced finite element-based contact modeling procedure has been applied to model the high-speed stage with the bearings fully modeled in order to evaluate strain levels. A major conclusion is that the strains of the slotted grooves are at such a level that they have acceptable signal-to-noise levels. This was verified by the results of the initial experiments presented here.
The performance of high-speed helical geartrains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction/torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High-Speed Helical Geartrain Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double-helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160â“250° F) and lubricating jet pressure (60â“80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling-off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears.
The U.S. Space Shuttle fleet was originally intended to have a life of 100 flights for each vehicle, lasting over a 10-year period, with minimal scheduled maintenance or inspection. The first space shuttle flight was that of the Space Shuttle Columbia (OV-102), launched April 12, 1981. The disaster that destroyed Columbia occurred on its 28th flight, February 1, 2003, nearly 22 years after its first launch.
Engineers typically learn that the bearing L10 life can be estimated using the so called âœC/P methodâ â” or the âœbasic rating lifeâ of the bearing, a method rooted in the 1940s. Major developments have since led to the âœmodified rating life,â released in ISO 281:2007, which includes the aiso life modification factor. In this paper a succession of equations used for bearing life ratings are reviewed, and current bearing life rating practices are discussed in detail. It is shown that â” despite the introduction more than 30 years ago of the adjustment factor of the basic rating life, and the standardization in 2007 of the aiso modification factor â” use of these improved calculation methods are not practiced by all engineers. Indeed â” many continue referring to the old model as a way of seeking compliance with existing, established practices.
The use of motor current signature analysis (MCSA) for motor fault detection â” such as a broken rotor bar â” is now well established. However, detection of mechanical faults related to the driven system remains a more challenging task. Recently there has been a growing interest for detection of gear faults by MCSA. Advantages and drawbacks of these MCSA-type techniques are presented and discussed on a few industrial cases.
Dave Soma, the mechanical supervisor at Leland Olds Station, a coal-fired power plant near Stanton, North Dakota, says he and his maintenance team care deeply about keeping the plant running and providing people electricity, especially in the dead of winter.
Our product focus includes the latest technology in gears and gear drives from the leading manufacturers.
Th e signing of a contract for more than 5,000 sets of SKFâ™s latest high-capacity cylindrical roller bearings (HCCRB) for wind turbines will impart added load-carrying capacity, more reliability and longer life to the Nanjing Gear Companyâ™s (NGC) line of gearboxes for wind generation applications.
Mean Time Between Failures is a very frequent and broadly used reliability measure of components, systems and devices used mainly in conjunction with electrical and electronic equipment.
With today's smaller, hotter - and overloaded - machinery, specifying the correct lubricant is vital.
This article describes how more sophisticated modeling techniques allow the latest software to identify design issues with bearings, shafts, gears and complicated multi-body systems.
Rising energy costs and concerns about global warming are at the forefront of todayâ™s news. Turn to local or national TV programming, browse the internet or read the paper and one can find numerous stories about the seemingly irreversible energy costs and the subsequent impact that these costs have on simply doing business. As a result, we as individuals are becoming increasingly aware of the cost of energy and we are being introduced to a variety of methods and/or products that will minimize the impact of these costs.
A recent trend has been a movement to more user-friendly products in the mechanical power transmission industry. A good example of such a product is a high-horsepower, right angle, shaft-mounted drive designed to minimize installation efforts. Commonly referred to as an alignment-free type, it allows the drive package mounting to be quicker, more cost effective and require less expertise during installation. This facilitates the use of the drive in applications such as underground mining, where there is little room to maneuver parts. The most common application for the alignment-free style drive is for powering bulk material handling belt conveyors.
The availability of high-strength shaft materials, in combination with bearings with high carrying capacity, allows use of slimmer shafts. However, the modulus of elasticity remains the same, so seat design for bearings and gears must be given close attention.
Volatile aerospace market keeps gear manufacturers guessing.
This article is designed to help describe the selection process of a reducer to be used in the parcel handling industry. It will go over the different applications for which gearboxes are used throughout parcel handling facilities such as UPS, FedEx and DHL.
In order to analyze the different gear oils suitable for the lubrication of wind turbine gearboxes, five fully formulated ISO VG 320 gear oils were selected. In between the selected gear oils, four PAO base oils can be found: PAOR, PAOM, PAOC and PAOX. A mineral-based oil (MINR) was also included as reference.
For the lubrication of open gear drives used in different industrial applications such as cement and coal mills, rotary furnaces, or where the sealing conditions are difficult, semi-fluid greases are often used in preference to fluid oils. For girth gear applications the greases are used with a splash or spray lubrication system. The selection of such greases influences pitting lifetime and the load-carrying capacity of the gears, as well as wear behavior
Worm, bevel, and parallel shaft gear units were installed at two breweries to provide the necessary process control.
In this study, a finite volume CFD simulation model of a single-stage injection-lubricated test gearbox was applied to investigate its oil flow and no-load power loss. The results provide physically plausible information on the oil supply and its distribution.
The proof of the reliability of a gear drive is now an additional requirement. In Europe, the acceptance authorities for wind turbines are requesting a system reliability proof from gearbox manufacturers. The AGMA committee reviewing the AGMA 6006 standard for wind turbines is considering adding a chapter about design for reliability. However, reliability considerations are not new; NASA, for example, was in the 1980s using reliability concepts for gear drives.
With the increasing mechanical power capacity of gearboxes, the thermal power limit tends to become the limiting factor. To achieve a balanced system, the gear unit needs extra cooling. Using a fan that is mounted to a fast rotating shaft is a common solution. For this solution an optimal design is investigated.
How one gearbox manufacturer took an existing design and transformed it to meet the needs of this demanding environment.
In this paper, the models for different power loss sources in transmissions from literature are applied and compared, which form the two methods - ISO 14179-2 and the joint model to estimate the power losses in a transmission. A 2-speed transmission in an electric vehicle is used as a case study to compare the two methods and validate them with experimental data.
Rolls-Royce is pioneering the UltraFan engine family architecture containing a planetary gearbox in a power range of 15 to 80 megawatts. To increase the efficiency of the UltraFan, a planetary gearbox is introduced between fan and intermediate pressure compressor. This enables running the turbine to rotate faster and allows a reduced fan speed.
Condition Monitoring Technology Evolves for Gear Drives, Gearmotors and Gearboxes. Here's a look at what some leading manufacturers are offering.
Prototype and Process Development Ensuring Stable Quality at the Highest Level
Schaeffler Touts System Solutions and Electrification Advancements at Detroit Symposium
A Look at Gear & Gear Drive Lubrication Performance Improvements
The complete Product News section from the March 2018 issue of Power Transmission Engineering.
A look at recent installations, plus interviews with some wind industry insiders.
Standardized calculation methods such as ISO 6336 and DIN 3990 already exist to determine the load distributions on gears inside a planetary gearbox, but by their very universal nature, these methods offer varying results depending on the gearbox design. Double helical gears, in particular, can benefit from more specific, complex algorithms to reach a maximum level of efficiency. Double helical gears interact with the rest of the gearbox differently than helical or spur gears, and thus benefit from different analytical models outside the standardized methods. The present research project describes the algorithm to determine the load distribution of planetary gearboxes with double helical gears.
The complete technical calendar from the February 2017 issue of Power Transmission Engineering.
Modern drivetrains with voltage-source inverters not only offer advantages like, for example, variable speed operation, increased efficiency and higher dynamics, but also an increase in failures caused by induced parasitic currents.
Gearboxes are important assemblies within mechatronic systems. During the design phase of such systems it is essential to know the gearbox behavior under consideration of dynamic interactions with its environment. Holistic system simulation helps the engineer to understand this and to improve, adjust, or optimize gearboxes and their application.
In the design of an automatic transmission gearbox, the variation of one parameter can result in different system performances due to the strong interdependencies among all components. For given transmission ratios, component lifetimes and safeties, or space restrictions, improvements in efficiency, noise, and weight can be achieved.
Approximately one quarter of all servo motors around the world require some type of gear reduction in their applications. From large satellite dishes to precision medical devices, gearboxes boost torque and reduce speed for servos in order for them to be sized more efficiently. While gearbox fundamentals haven't changed much over the past 20 years, their effectiveness has improved significantly, driven mostly by the need to accommodate advancements in servo technology.
Gear drives focus on longevity, quality and customization.
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