-Parker Hannifin

Recent ideas to reduce maintenance costs and simplify lubrication routines in the nacelle include switching to one lubricant for all bearings. Another is an adhesive grease for open gears. The grease is said to provide good adhesion and protection against high loads and corrosion. It is well suited to lubricating gears in pitch and yaw drives, while reducing the risk of migration inside the nacelle and onto the tower.

Another recent lubricant for wind turbine gearboxes provides a high viscosity to address cold weather effects, without need for additional viscosity-index improvers. It has a higher heat capacity than hydrocarbon oils, which lets it transfer more heat, forestalling a shutdown when turbine output is at its maximum. The lubricant has better lubricity at ambient conditions, and so has potential to shift a turbine’s power-versus-wind-speed curve to the left, leading to greater power output when it is less than maximum. Lubricants of this sort are also said to address the issue of micropitting, which can lead to wearing and changes in gear teeth shape, reducing gear accuracy, and increasing vibrations and noise. High-viscosity lubricants provide a relatively thick lubricant film that can help reduce debris and worn particles that often accompany less well-lubricated gears.

The demand for larger MW-class turbines, and the goal of further improvements in reliability and protection under extreme conditions are driving development of a new generations of high-performance industrial lubricants and greases. For example, one lube formulator recently announced the introduction of a portfolio of lubricants and greases for the wind sector specifically for main gearbox, yaw and pitch drives, bearings, hydrostatic, and hydraulic systems. The portfolio is based around three tiers: mainline, premium and advanced, with advanced often using the latest synthetic-lubricant technology.

Operating turbines in remote areas with extreme climatic conditions adds to the lubrication challenge. Whether it’s to extend maintenance intervals and increase reliability with purpose-designed, low-temperature hydraulic oils, or to protect blade bearings from fretting corrosion and false brinelling there is a wide range of lubricants from which to choose.

A few specialized lubricants with characteristics intended for particular tasks include low-temperature fluidity and long oil life. Such a lubricant provides benefits for difficult to maintain wind turbine gearboxes. The lubrication know-how is such that synthetic gear oils can offer protection from common failure modes, including micropitting and bearing wear. Another formulation of synthetic gear oil is intended for yaw and pitch drives. And greases are formulated to protect bearings against fretting corrosion, moisture contamination, and false brinelling at Parker Hannifin temperatures as low as -55ºF

Windpower Engineering & Development

Castrol has begun production of Optigear Synthetic X320 at its manufacturing plant in Warminster, Penn., to help it better serve Siemens operations in the U.S.

Turbine OEM Siemens Wind Power has signed a purchase agreement with lubricant manufacturer  Castrol Industrial  for its gear oil, Castrol Optigear Synthetic X 320. Castrol Industrial says it will be the exclusive supplier of gearbox lubricants for the OEM. The lubricant company says it also supplies complementary products to the OEM, such as hydraulic fluids and greases.

Because of the agreement, Castrol has begun production of the gear oil at its manufacturing plant in Warminster, Pennsylvania, to help the company better serve Siemens operations in Hutchinson, Kansas, and supply locally-produced lubricants to other customers in the U.S. and surrounding markets.

Sven Thiesen, Key Account Manager Wind Energy, Castrol Industrial, says: “The deal is the latest in a long-standing working relationship with Siemens, which recognizes the importance of working with partners to ensure consistency and quality in all markets.”

The company says its Optigear Synthetic X 320 can offer a significantly greater resistance to micropitting, providing gearbox protection under high loads, and preserving turbine components longer. It also creates a 5 to 10% thicker oil film to improve gearbox protection and cut wear, while smoothing surfaces resulting in minimal wear or damage.

While Castrol Industrial ships its oil from Europe to serve the Chinese market, the company says it continues evaluating the option of manufacturing at its Taichang plant in China to meet the growing demand in the region, which represents significant future potential.

Castrol Industrial
www.castrolindustrial.com/WindEnergy

Windpower Engineering & Development

Klüber’s NH1 94-6000 is said to reduce gear wear and extend maintenance intervals due to its load-carrying capacity and corrosion protection.

A recently developed synthetic fluid gear grease is said to be ideal for manufacturers in industries that use centralized lubrication including wind, power transmission, and food. The synthetic fluid gear grease, NH1 94-6000, is based on highly refined synthetic hydrocarbon and a special calcium complex soap thickener. It is NSF H1 registered and therefore safe for incidental, technically unavoidable food contact.

The grease provides excellent wear protection even at a soft consistency of NLGI 000. At the same time, Klüberfood NH1 94-6000 is said to offer excellent corrosion protection along with good water resistance. This combination of special synthetic base materials also enables optimum lubricant supply in cold or refrigerated environments. Applied through the central lubrication systems, the lubricant can be used as gear grease for the immersion lubrication of toothed and worm gears or chains, as well as other friction points such as bearings and linear guides.
Klüber Lubrication
www.kluber.com

Windpower Engineering & Development

Klübersynth RA 44-702 has good resistance to abrasion and has been tested on more than 100 standard and customized rigs to surpass the stringent requirements of the automotive industry.

A manufacturer of lubricants has developed a fully synthetic, high-viscosity grease for the lubrication of plastic parts inside cars. Klüber Lubrication says its Klübersynth RA 44-702 does not contain any silicone and mechanically dampens and reduces noise of slowly moving parts. The grease, which has no odor, can be used for both plastic/plastic and plastic/metal material pairings.

Oils or bonded coatings are applied to hundreds of points in every car, including brakes, steering assembly, engine components, gear shift, clutch and gears, or in seemingly minor components like door modules. Its manufacturer says Klübersynth RA 44-702 helps reduce oscillation, noise, and vibration and provides a pleasant high-quality feel when handling the car components, even at low temperatures. For example, the grease can greatly improve the feel of operating switches or adjusting armrests and seat rails. Other applications include mechanical switches and rotary controls, ventilation flaps, sun visors, ashtrays, cup holders, storage boxes and sunroofs.

 Klüber Lubrication www.klubersolutions.com

Windpower Engineering & Development

“Choosing the right lubricants for your wind turbines can help to make a real difference to the efficiency of your operation,” said Felix Guerzoni, product application specialist with Shell Lubricants.

Keeping wind turbines working efficiently and reducing operating costs is critical for a profitable business. Choosing the right lubricants and services can help to make a real difference to a power generation operation. Technology-leading wind turbine lubricants that are developed, researched and supported by wind professionals can help to reduce operating and equipment-ownership costs by providing:

• • Enhanced protection of critical components to reduce replacement costs and extend turbine life
• • Reduced lubricant consumption and maintenance through extended-life products
• • Improved operational efficiency through synthetic oil technology

Operating turbines in remote areas with extreme climatic conditions adds to the lubrication challenge. Whether it’s to extend maintenance intervals and increase reliability with purpose-designed, low-temperature hydraulic oils, or to protect blade bearings from fretting corrosion and false brinelling there is a wide range of lubricants from which to choose. Some of the leading products Shell Lubricants offers to meet these demands are:

• 

  Omala S4 GX - Offering excellent low-temperature fluidity and long oil life, this lubricant provides benefits for difficult to maintain wind turbine gearboxes.

  Shell Omala S4 GX 320 (previously Shell Omala HD 320) synthetic gear oil offers protection from common failure modes, including micropitting and bearing wear

• Shell Omala S4 WE 150 & 320 (previously Shell Tivela S 150 & 320) synthetic gear oil for yaw and pitch drives, which is widely used as factory fill by yaw and pitch drive manufacturers
• Shell Malleus GL & OGH open gear grease
• Gadus S5 T100 electric motor bearing synthetic grease and Shell Gadus S5 T460 main bearing grease

• Shell Rhodina BBZ grease protects bearings against fretting corrosion, moisture contamination and false brinelling at temperatures as low as -55ºF
• Shell Tellus S4 VX 32 (previously Shell Tellus Arctic 32) is used as hydraulic fluid for extreme-climate wind turbines

Windpower Engineering & Development

Another lubricator, a 24-Vdc electric-powered device, greases heavy-duty equipment without tapping into hydraulic or pneumatic lines. It is said to set up easily and fit directly onto a 5-gallon grease pail. It works with a hose reel and hand grease gun, and can be used stand-alone or with a centralized lubrication system. It weighs about 24 lbs. A metal follower plate has a wiping seal on its circumference. The follower plate works in straight or tapered pails, and ensures the complete removal of grease from a container. The pump can refill automated lubrication systems inside wind turbines or act as the driving pump behind the system. Its maximum discharge pressure of more than 4,000 psi is one of the industry’s highest. Discharge volume is 80 to 120 grams/min in continuous operation and 70 to 80 grams/min in 30-min periods. Operating temperatures range from 14 to 104°F.

Trends: Hydraulic-component companies are designing more complete lubrication-oil systems for wind-turbine gearboxes. These systems would come with filters, pumps, valves, coolers, and heaters as well as manifolds and piping to connect components. The advantage here is that the assemblies are probably more thoroughly tested and proven and carry the assurance of reliability from a qualified supplier.

Tools: The equipment used to maintain the machinery in a nacelle are much like those used by other technicians except they are fitted with tethers to prevent them from falling many feet to the ground. See the safety and bolting sections for additional discussions.

Cold weather filters: A recent element intended for wind turbines is said to ensure sufficient and effective filtration levels and prevent the filter from going into bypass mode, an event common to cold starts. Also, offline filters can remove water from oil. Existing systems on turbines can be upgraded with these capabilities.

Windpower Engineering & Development

Recent ideas to reduce maintenance costs and simplify lubrication routines in the nacelle include switching to one lubricant for all bearings. Another is an adhesive grease for open gears. The grease is said to provide good adhesion and protection against high loads and corrosion. It is well suited to lubricating gears in pitch and yaw drives, while reducing the risk of migration inside the nacelle and onto the tower.

Another recent lubricant for wind turbine gearboxes provides a high viscosity to address cold weather effects, without need for additional VI improvers. It has a higher heat capacity than hydrocarbon oils, which lets it transfer more heat, forestalling a shutdown when turbine output is at its maximum. The lubricant has better lubricity at ambient conditions, and so has potential to shift a turbine’s power-versus-wind-speed curve to the left, leading to greater power output when it is less than the maximum design output. Lubricants of this sort are also said to address the issue of micropitting, which can lead to wearing and changes in gear teeth shape, reducing gear accuracy, and increasing vibrations and noise. High-viscosity lubricants provide a relatively thick lubricant film that can help reduce debris and worn particles that often accompany less well-lubricated gears.

Particle detectors: These sensors look for debris in oil. Small ones can occupy less than 150 in.3 yet provide contamination control. A few features of such devices include monitoring system contamination trends, and early warning Leds or digital-display indicators that tell of low, medium, and high contamination levels. One unit boasts of needing only 3 sec to take a sample, and works at flow rates of 40 to 140 ml/min. Working pressure can be up to 6,000 psi.

Windpower Engineering & Development

Global lubricant demand is forecast to reach 40.5 million metric tons in 2012. According to a recent study, the market is estimated at $48.8 billion. Companies in this booming market are expanding their lubricant lines to include those for more industries such as wind. Wind equipment requires specialized lubricants. For instance, they may require certain blends of base oil and additives to cover different lubrication requirements of individual bearings in wind-power stations. One trend has been toward reducing maintenance costs and simplifying lubrication routines in the nacelle. Also, as wind turbines are built higher and in more extreme conditions, the trends is toward using low-viscosity lubricants to address cold weather effects, produce more power, and decrease micropitting. Also, engineers are using specialty synthetics instead of mineral oils, along with particle counters to control contamination.

To reduce maintenance costs and simplify lubrication in the nacelle, operators are using one lubricant for all bearings. “Repairs on wind turbines can be costly, difficult, and dangerous,” says Jesse Dilk, wind industry manager at Klüber. “Therefore, it is vital to use high-quality components at every opportunity. Bearings, seals, and lubricants are essential design elements when analyzing mechanical systems. Optimizing these elements leads to a more efficient, reliable machine design.” For example, Klüber’s high-performance grease has a blend of base oil and additives to cover different lubrication requirements of individual bearings. Another adhesive grease lubricates gears in pitch and yaw drives, while reducing the risk of migration inside the nacelle and onto the tower.

Also, the industry has moved toward using synthetics instead of mineral oils to minimize maintenance. “The lubricants tend to be well balanced, and have been widely tested in laboratory rigs and in the field,” Dilk says. “The preference for synthetics include high wear protection, higher efficiency from lower friction, and a wide operating temperature range. Specialty synthetic lubricants typically outperform mineral-based versions under the same conditions. Synthetics are further driven by a requirement for extended lubrication intervals.” Exxon Mobil Corp. engineers also say synthetic gear oil protects against micropitting, scuffing wear, and corrosion. Synthetic oils function over a wide temperature range and resist deposit formation. Furthermore, many new lubricants and greases extend oil change intervals from a matter of months to years, which significantly reduces time and cost of maintenance.

Shell Lubricants also says it recognizes the significance of reduced reliability and demands of operating wind farms in remote locations (on and offshore) and in harsh climates. Their engineers have developed a variety of lubricants to withstand extremely low temperatures and protect against micropitting and bearing wear. Another trend is to monitor the oil conditions, especially in gearboxes. Shell, for example, offers an oil-analysis program that can help operators monitor the condition of their lubricant along with equipment that helps avoid unscheduled downtime.

Finally, particle counters, such as those from Parker Hannifin Corp., provide contamination control for lubricants. Such units independently monitor system contamination trends, and give early warnings. LEDs or digital displays indicate low, medium, and high contamination levels. Such advancements, keep oil clean and increase its lifespan.

WPE

Windpower Engineering & Development

The company has developed lubricants that exceed OEM standards to protect and maximize the performance of next generation of wind-turbine gearboxes.

Some features include:

• Higher resistance to micropitting. Synthetic X 320 offers greater gearbox protection under high loads, preserving turbine components longer.
• Greater Protection against component damage. X 320 has demonstrated, says the company, less component weight loss to protect the gearbox from fatigue and wear. Independent testing measuring component weight loss demonstrated that X 320 offers significantly more protection against potentially damaging micropitting than the global market leader’s product.
• Smooth surfaces.  Synthetic X 320 can smooth surfaces resulting in minimal wear or damage. After 9 hours of testing, X 320’s friction modifiers helped smooth surface damage, halting the effects of micropitting leading to gearbox damage or failure.
  

  While competing products exhibited further wear, Castrol Optigear Synthetic X 320 showed significantly lower wear and stabilized the system after 5 h, after which little or no wear occurred in the 9 h micropitting test.

Low fluid friction in the load zone of gears and rolling-contact bearings is key to top performance and life expectancy of a turbine. Low fluid friction also lowers operating temperatures and improves gear efficiency, reducing power consumption and extending part life by reducing the extent of damage caused by micropitting.

Repeated independent micropitting test results show that Synthetic X 320 exhibits lower average friction coefficient compared with competing products that protect a gearbox from micropitting, and captures more energy from less wind.

The company says it has performed extensive testing against OEM and turbine manufacturers’ specifications so it can provide lubricants for all applications in wind turbines.

Castrol
Castrol.com

Windpower Engineering & Development

The pump unit for the Timken’s Wind Energy Lubrication System holds about eight liters of grease.

Due to long, continuous operations, wind turbine main-shaft bearings need consistent, reliable lubrication. Timken’s Wind Energy Lubrication System addresses such needs with a single pump, in two models capable of working with either series-progressive or injector-based lubricant delivery methods. Timken says the HP pump model provides continuous lubrication with a conventional method of pressure purging old grease. An LP version uses an active-purge system that removes old grease without internal bearing-cavity pressure.

Timken says a rugged and versatile pump is at the heart of both units. They feature powerful pump performance for consistent delivery of grease up to NLGI No. 2 and excellent “cold climate” pumping properties. An offset piston element reduces side loading, while increasing pump life from a standard 24 Vdc power connection (115/230 Vac is optional). CPC and DIN style power-connection are options. An 8-liter standard grease reservoir allows once-yearly turbine maintenance with stirring paddle and wiper to minimize air pockets and grease separation.

Three fill ports simplify lubricant refilling when mounted in tight areas. Advanced flow elements reduce stagnant grease flow to the pump inlet. In a conventional method of grease movement, fresh grease is pushed into the cavity. It finds a path of least resistance around accumulations of old grease. This allows inadequate replenishment of grease in one of the bearing rows.

An active purge system removes old grease mechanically and by suction at the exit side of each bearing row for freer grease movement. Minimal amounts of fresh grease are directed to each row, providing positive replenishment and assuring that neither row is starved for lubrication.

The lubrication units also sport a clever and patented charger, which mechanically charges old grease into an orifice where it can be removed by suction. The ability to remove grease without cavity pressure improves seal function because it provides optimum lubrication.

Knowing how much and how often lubricant can be introduced to critical bearing contact areas is a primary challenge to obtaining proper lubrication of any bearing. Common practice in a two-row bearing is to provide a single grease-injection inlet between the two bearing rows. Over time, this can cause uneven lubrication in each row due to aged grease accumulating near the inlet. Accumulation then forces fresh grease to a path of least resistance, potentially starving grease to one of the bearing rows. The LP lubricator addresses the issue with a low-pressure centralized-lubrication system that directs grease to inlets and uses an active purging method to reliably lubricate bearings. The system’s central pump delivers lubricant through a supply line to multiple banks of injectors. When used with tapered roller bearings, each injector bank operates independently to lubricate each bearing row at the small end of the roller. Lubricant naturally pumps to the large-roller end where the grease is then “charged” into outlet ports and suction elements powered by the grease pump, which pull old grease to a waste container.

Timken Co.

www.timken.com

Windpower Engineering & Development