It is important to understand the factors that affect the operation of your generator set so you can be confident you have the right equipment for your application. Get what you need with these steps.
PROJECT PARAMETERS The ďŹrst step is to establish project parameters.
⢠Minimum generator-set load/capacity: Running a generator set under light load can lead to engine damage, reducing reliability. Load banks should supplement the regular loads when loading falls below the recommended value.
⢠Maximum allowable step voltage dip: As you reduce the maximum allowable step voltage dip during initial startup, when loads cycle under automatic controls or when high peak loads operate, you need to increase the size of the generator set speciďŹed. Choosing lower allowable voltage dip requires a larger generator set.
⢠Maximum allowable step frequency dip: As you reduce the maximum allowable frequency dip, you increase the size of the generator set needed.
⢠Altitude and temperature: Based on the site location, the size of the generator set must increase for a given level of performance as altitude and ambient temperature rise.
⢠Duty cycle: Generator-set size is also inďŹuenced by whether the application is for standby power, prime power or utility paralleling. Standby power systems generally have no overload capability. Prime power systems generally have a minimum of 10 percent overload capacity. Generator sets that are intended to operate extended hours at steady constant load should not be operated in excess of the continuous rating.
⢠Fuel: The preference for gas, diesel or LP will affect generator-set choices. Often, generator sets running on gas or LP must be oversized due to derating. Emergency systems typically must be supplied by fuel stored locally.
⢠Phase: Select either single or three-phase. The three-phase selection permits single-phase loads but the assumption is that the single-phase loads will be balanced across the three phases.
⢠Frequency: Either 50 Hz or 60 Hz.
⢠Voltage: Voltage choices are usually a function of selected frequency.
LOADS The next step in sizing a generator set is to identify every type and size of load the generator set will power. In general, when non-linear loads are present, it may be necessary to oversize the alternator. Following is a general discussion of how various loads and electrical factors affect the sizing of generator sets.
⢠Power factor (PF): This is the ratio of kW to kVA and is expressed as a decimal ďŹgure (0.8) or as a percentage. Three-phase generator sets are rated for 0.8 PF loads and single-phase generator sets for 1.0 PF loads. Lower PFs require larger alternators or generator sets to properly serve the load. Caution should be used whenever applying generator sets to leading power factor loads. Only slightly leading power factor can cause generator sets to lose voltage control.
⢠Single-phase loads and load imbalance: Single-phase loads should be distributed as evenly as possible between the three phases of a three-phase generator set in order to fully utilize generator set capacity and limit voltage imbalance.
⢠Peak loads: Peak loads are caused by loads that cycle on and off, such as welding equipment or motors. Taking cyclic loads into account can significantly increase the size of the recommended generator set despite painstaking efforts to place loads in a step starting sequence.
⢠Motor loads: Calculating speciďŹc motor loads is best handled by sizing software which will convert types of motors into load starting and running requirements. For this discussion, however, it is sufficient to broadly characterize loads as high-inertia or as low-inertia loads for the purpose of determining engine power needed to start and accelerate motor loads.
⢠Low-inertia loads include fans and centrifugal blowers, rotary compressors, rotary and centrifugal pumps.
⢠High-inertia loads include elevators, single and multi-cylinder pumps, single and multi-cylinder compressors, rock crushers and conveyors.
⢠Motors over 50 HP: A large motor started across the line with a generator set represents a low-impedance load while at locked rotor or initial stalled condition. The result is a high inrush current, typically six times the motor rated (running) current. The high inrush current causes generator voltage dip, which can affect other systems. The manner in which generator voltage recovers from this dip is a function of the relative sizes of the generator, the motor, engine power and generator excitation forcing capability. Depending on the severity of the load, the generator should be sized to recover to the rated voltage within a few seconds, if not cycles. Various types of reduced-voltage motor starters are available to reduce the starting kVA of a motor in applications where reduced motor torque is acceptable.
⢠Variable frequency drive (VFD) motors: VFDs are non-linear loads used to control the speed of induction motors, induce distortion in generator output voltage. Larger alternators are required to prevent overheating due to the harmonic currents induced by the VFD and to lower system voltage distortion by lowering alternator reactance.
There are also other types of loads to consider, including uninterruptible power supplies, battery chargers and regenerative loads (for applications such as elevators, cranes and hoists where the power source is often relied upon for absorbing power during braking).
LOAD STEP SEQUENCING In many applications, the generator set is sized to pick up all loads in one step. In some applications it is advantageous to start up the loads that cause the largest starting surge ďŹrst and then the rest in multiple steps â the largest-motor-ďŹrst rule. Codes may require sequenced load starting to start emergency and life safety loads within as little as ten seconds, while allowing other loads longer periods of time. In general, sequenced startup allows the smallest generator set in relation to the steady state load. When cycling motor loads exist, it will still be necessary to size the generator set to start the largest cycling motor last, with all other loads connected.
FUTURE NEEDS Power use is not ďŹxed and tends to grow over time. Therefore, any generator-set sizing exercise needs to take system expansion into consideration. Even with sophisticated software solutions, the ďŹnal decision on generator-set size needs to be tempered with judgment. And, the more you know about the parameters that affect sizing, the better that judgment will be.
Jim Iverson is a senior applications engineer for Cummins Power Generation. For more information, visit www.cumminspower.com.
Too Big to Fail: Predictive maintenance protects heavy-duty mobile assets
Ultrasound as a predictive maintenance (PdM) tool is used in many applications in industries of all kinds as an inspection tool for detecting positive and negative pressure leaks, such as those found in compressed air systems or vacuum pumps. Some industrial processes use ultrasound to identify failed steam traps, and all facilities derive safety benefits from its ability to find electrical faults. Most recently, PdM professionals have opened their eyes to the benefits it offers as a predictive technology, giving early alert that an impending problem is developing in a bearing or helping to optimize the lubrication of rotating equipment.
All of these valuable applications contribute to billions of dollars saved in downtime, energy efficiency and improved product quality. Perhaps most interesting of all is that most of these inspections are carried out on fixed assets.
However, in many companies, such as mines and quarries, the production cycle depends on heavy vehicles, loaders and off-road vehicles. These have a range of applications, such as moving goods from land points to sea ports and beyond, excavate earth and move thousands of tons of raw materials in quarries and open-pit mines.
Although their size can vary between 30 to more than 350 metric tons, they all have in common an internal combustion engine to provide the power to move the vehicle. Most have a cabin to keep the operator safe, dry, warm or cool while others have storage volumes, which must be weather tight and hermetically tight in the case of chilled-container transports. And in many cases, compressed-air systems are used for breaking and suspension systems.
To protect the investment in these mobile assets, preventative and predictive maintenance is performed on a regular basis. Most fleet managers rely on oil analysis for PdM â while other PdM technologies, such as ultrasound, vibration and infrared, are seldom considered. Additional investments in these technologies is not a priority; however, there are several important applications that can be served with ultrasound technology that are not currently understood.
How does it work? Many people in maintenance departments of factories responsible for fixed assets know that the principle source of ultrasonic waves is turbulent flow, friction and discharge related to electrical problems. They also know ultrasound waves are sound waves vibrating over 20,000 Hz, which is impossible for humans to hear without the help of special instrumentation, such as an SDT170 ultrasonic measurement instrument.
Early stage problems produce ultrasonic signals that are transmitted from the source as ultrasound pressure waves. The instrument detects these waves and translates them into an audible signal that can be heard by the inspector, all the while measuring the ultrasound signal so it can be compared and trended to determine gradual deterioration.
A growing demographic of qualified and skilled ultrasound inspectors is poorly represented in the mobile maintenance shop where the technology is virtually unknown, and sadly, many cost-saving applications have not been revealed. If you are working in the maintenance department responsible for mobile asset maintenance, look for applications in diesel engines, hydraulic cylinders, air-braking systems, air suspension and cabin tightness.
Diesel Engines Internal combustion engines burn fuel, and regardless of size, they require air. The air we breathe is the same air engines breath. No matter where we are on the planet, air contains particles in suspension. Some of these particles are harmless, but others represent a serious danger. Silica ranks as one of the hardest elements on earth â and also the most abundant.
All diesel engines have primary and secondary filters fitted between the air intake vents and the turbocharger. When the engine is operational, a negative pressure is created in the air intake system, and any leaky orifice (loose clamps, cracked hoses, pin holes) downstream of the filters means the engine is breathing without filtration. This means air full of silica can reach the pistons, rings, sleeves and other engine components, causing damage and premature failure.
Oil analysis is used as a predictive tool, comparing the metal content and silica in parts per million (PPM) found in the oil sample against limit values set according to the engine manufacturer. When a sample shows values over the limit, the contamination source needs to be found quickly and the mobile asset must be removed from service to avoid further damage. As a companion to visual inspection, ultrasound testing to find the leak will net quick results.
⢠Inspection with the engine running: Start the engine and leave it to idle. With noise attenuating headphones, adjust the sensitivity of the SDT170 according to the ultrasound sources near the engine. Using the flexible sensor for safety (if you have one), inspect the entire intake system starting from the air breather and ending at the turbocharger. Any air ingress will produce an ultrasonic signal that sounds like the hissing, swooshing sound you know from a compressed air leak.
A well-trained ear will pick up this sound quickly despite competing noises. Additional training teaches ultrasound inspectors how to deal with parasite noise and harsh environments and is highly recommended for mobile mechanics that are adopting ultrasound testing.
⢠Inspection with the engine turned off: The air intake system can also be inspected for leaks when the engine is not running. In fact, this may be more desirable if the parasite noise from the engine is too much. In lieu of turbulent flow, we can generate artificial ultrasound signals in the air breather system. This is done by means of an SDT 200mW Bi-Sonic Transmitter, a small accessory that generates a 40-kHz signal powerful enough to fill small volumes. The signal can be heard and measured directly through the various membranes that make up the air breather system.
A large mining company in northern Canada recently shared their experience inspecting the air intake on a LeTourneau production loader. In response to very high levels of silica and iron from oil samples, an attempt was made to determine if there were any leaks in the breather system. A visual inspection failed to produce any definitive results. A second check of the breather system was conducted using airborne ultrasound. Finding the leaks was easy, the mining company reported, and the mechanics reported that the fix was relatively simple once the leaks were discovered. The production loaderâs oil was re-sampled after about 48 hours operating in the field, and all indications of dusting had disappeared. Ultrasound inspection of air intake systems is now standard practice at this site.
n Hydraulic Cylinders: Hydraulic cylinders are widely used in fixed and mobile hydraulic systems. Seals are one of the most important components: they create a barrier between the high-pressure and low-pressure chamber. When the integrity of seals is compromised, the cylinder no longer transmits its full force potential. A sure symptom that the cylinder has problems is a loss of power and/or slow operation. In severe cases, the cylinder can stall even under light loads. An increase in pump noise and temperature is also a sign of leaking cylinders. A leading cause for failures is contaminated fluid.
A conventional method to check for leaks requires an operator to run the piston to one end of its stroke and leave it stalled in this position under pressure. Then they crack the fitting at the same end of the cylinder and check for fluid leaks. This is time consuming and requires the asset to be out of service for a longer time than necessary.
Ultrasound can speed this up, and in many instances, the inspection is performed in the field, avoiding the cost and delay to float the equipment back to the repair bay. The inspector places the contact sensor or magnetic sensor over the barrel near the piston. The system is put under pressure and the sensor scans around the barrel 360 degrees while listening for the characteristic sound produced for a leak when the fluid pass from the high to low-pressure chamber. This sound could be that made by small bubbles of oil bursting on the non-pressure side of the wiper. In the case of larger leaks, the sound is more like a squishing sound as oil is forced across a small orifice in the seal. The point where the signal is most intense indicates the integrity breach of the seal.
Air-Operated Brake Systems Air-break systems are used in all type of trucks, buses and rail cars. For an efficient operation, the system must be absolutely tight. Brake-systems manufacturers establish pressure guidelines for all circumstances, and this working pressure must be maintained. These systems have several parts, including the compressor, an air dryer, valves, air reservoir tank, pipes, fittings and the system itself â all susceptible to leaks.
Finding the leak is easy and fast. In fact, many manufacturers â including Volvo Trucks and Mack Trucks â already use SDT170 detectors on the assembly line to ensure leak-free brake systems. Start the engine and let the compressor run until the required pressure is reached in the system. Turn off the engine and, using the detector with the flexible sensor, scan from the compressor side to the brakes in the wheels.
The hissing sound of any leak will be easily heard, and because itâs ultrasonic, itâs directional and easy to localize.
Air-Suspension Systems Air-suspension systems provide a much smoother ride, which can add protection to cargo that is sensitive to transportation shocks. The air spring is basically a bellow filled with compressed air and run off the same compressor that the braking system uses. Leaks in the air suspension system affect the smooth ride, but also can draw on the brake system making it unreliable, and therefore unsafe.
There is, of course, the added risk for a vehicle transporting several tons of cargo; when the air spring loses its pressure, there is the chance of balance loss and tipping. Troubleshooting air suspension systems is essentially the same procedure as that used for braking systems.
Cabin Tightness A final but important application where ultrasound inspection is usefully employed ensures the tightness of cabins and cockpits. In smaller vehicles, tightness is important to prevent noisy interiors from wind noise and water leaks. On larger mobile assets like loaders and tractors, keeping micron sized dust particles out of the cabin is a comfort and health issue for the operators.
The inspection is simple: place a 200-mW tone generator inside the cabin and close all windows, doors and vents. Using the SDT170 and flexible sensor, scan the outside seals on all windows and doors. The artificial ultrasound source is powerful enough to fill the entire cabin and transmit directly through glass and steel. Follow this procedure to understand the difference between a leak and non-leak.
While great progress has been made applying ultrasound to inspections on fixed assets, there are equal wins to be gained from applications on mobile assets.
As ultrasound technology proliferates around the globe, one canât help but wonder what other simple applications exist that will help a company save the next million dollars.
Allan Rienstra is the CEO of SDT North America in Cobourg, Ont. Gus Velasquez is an account manager for the Latin-American region with SDT. For more information, visit www.sdtnorthamerica.com.
Regardless of specific industry, the resource sector is highly dependent upon mechanical equipment to power its operational processes. With up to 70 percent of mechanical failure directly/indirectly attributed to ineffective lubrication practices, resource-type reliability is intrinsically linked to good lubrication practices (GLP).
And there's no end of candidates ready to benefit from GLP. For example, they can include: gear-driven pumps, fans, conveyors, gas/air compressors, generators, cranes, scoop trams, haul trucks, hydraulic systems and couplingsâvirtually anything on the move!
Harsh conditions associated with the resource sector manifest themselves in different ways. Oil and gas plants are often found in remote locations, requiring the correct choice of lubricant, which is capable of working in both hot and cold extremes. Mining operations can also place temperature demands on equipment, often accompanied by dirt and water that require a suitable lubricant, excellent filtration and consistency of lubricant application.
Poor accessibility to lubrication points is often experienced in elevated transfer equipment, such as cranes and conveyors. This requires an engineered approach to provide consistent lubrication similar to that of an automated single-point lubricator. Resource sector material handling apparatus and vehicles are designed to take a great deal of abuse, and as a result, are often neglected.
What you need is a diligent approach to lubrication (i.e. an automated lubrication delivery system and wear particle analysis that's used to determine oil change time based on the oil's condition). The harsh, remote environments found in the resource sector accelerate the need for an engineered lubrication management program. Currently, there's no better place to commence your "reliability" initiative than by implementing, or updating your current approach to lubrication.
Equipment-related wear is caused by frictionâchoosing the wrong lubricant, applying the lubricant incorrectly, at the wrong time, or allowing the lubricant to become contaminated. This results in raising the level of friction that retards bodies in motion. More energy is then required to overcome the effects of friction.
For little or no capital outlay, adopting a seven-step engineered approach toward your lubrication efforts will result in the following: significant energy cost reduction; reduced lubricant inventories, consumption and spills; cleaner equipment; reclamation and reuse of existing lubricants; responsible disposal of old lubricants; and a significant increase in equipment reliability, availability and throughput.
Step One: Consolidate your lubricants
Many companies will carry an inventory of 20 or more lubricants throughout their facilities, often stored in half-open containers, exposed to atmospheric contamination and in danger of being spilled. Today's lubricants are capable of out- performing many of the lubricants you have continued to use and purchased over the past decades. Consolidation programs can easily reduce lubricant inventories by up to 75 percent and higher depending on the industry. This leads to lower purchase and carrying costs and a simplification of the lubricant application program. Investigate the use of synthetic lubricants in situations with extreme temperatures.
Consolidation forces you to inventory all of your lubricants in the facility and list every storage location. Engage with your lubricant suppliers and have them bid on performing a lubricant consolidation exercise. This program is usually offered at little or no cost, in exchange for blanket orders that can also work in your favour by fixing lubricant costs for a set period.
Step Two: Contamination control
Contamination is an enemy of both wear surfaces and lubricants. Fortunately, it can be controlled with a little effort and awareness. Contamination issues are largely caused by poor storage, handling and application practices. Fine tolerance bearing surfaces and radial lip seals don't take kindly to lubricants carrying abrasive bodies to the wear surface.
Nonetheless, we continually grease nipples without first cleaning the grease gun and the nipple, leave off reservoir lids and breather caps on hydraulic systems, ignore lubricant container lids and store barrels of lubricants in the outside extremes of weather to rust and collect water. We also use non-dedicated and dirty lubricant transfer devices. Review how you keep contaminants from ingressing your lubrication systems and develop improved housekeeping practices. Also invest in one of the many new-dedicated lubricant transfer systems offered by your local industrial supplier.
Step Three: Filtration
Poor machine filter management can manifest as reduced lubricant flow and cause the bypass of deadly wear contaminants to your bearing surfaces. Ensure filter replacement is made a high priority as part of your preventive maintenance program. In an effort to conserve and reuse lubricants, an external pump/filtration cart can be used to clean your large reservoir lubricants and ready them for reuse. This saves lubricant, change out and disposal costs. Contact your local lubrication hardware or filter supplier for details on this easy-to-use system.
Step Four: Spill containment
Oil spills are never easy to deal with; prevention can result in a lot less effort should a spill occur. When storing lubricants, ensure all full or partially full containers are kept in an area protected by an impermeable berm used to contain the spill in a localized area. The containment system can be a steel box tray, a concrete berm system, or one of the many plastic containment systems sold by your local industrial supplier. Just in case, don't forget to have on hand a spill management kit.
Step Five: Engineered lubricant delivery
Both under and over lubrication will cause a significant spike in energy requirements (one to overcome the metal-to-metal collision and the other to overcome fluid friction). Tuning your lubricant delivery can result in energy savings as high as 20 percent. Invest in a lubrication operation effectiveness review (LOER). This will enable you to improve your current approach to delivering the right lubricant, in the right amount, in the right place, at the right timeâwhether it be from a grease gun, or fully automated lubrication system.
Step Six: Disposal program
Local legislation is increasingly forcing companies to own their waste and put in place a disposal plan or program. Many organizations operating under a consolidated program have also been able to set up a recycling initiative. Old reservoir lubricants are taken back, cleaned, reconstituted with additives and resold to the originating company as recycled oil at savings of up to 25 percent of virgin oil.
This not only saves the environment, but also reduces the purchase cost of new oil for maintenance departments. Collecting oil by type makes it easier for the disposal company to reduce disposal costs charged to you. Check with your disposal company to see what programs are available, which you can take advantage of immediately.
Step Seven: Lubrication training
A little basic lubrication training can significantly boost understanding and enhance your program. Surprisingly, lubrication on the surface appears very intuitive in nature. At the same time, however, it's perhaps the least understood area of maintenance. Investing in a basic course that's focused on lubrication training will facilitate your program immensely.
Ken Bannister is the author of the best selling book, Lubrication for Industry, and the new lubrication section of the 28th edition of Machinery's Handbook, published by Industrial Press. He performs lubrication effectiveness reviews and lubrication training programs for all industries. You can reach him by email at
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. This article was previously published in REM magazine.
Improving productivity and reducing costs at Vale Incoâs Voisey Bay operation
ABB has won a renewal from Vale Inco Newfoundland & Labrador for all maintenance-related activities covering plant production equipment at its Voiseyâs Bay facility in Canada. The aim is to improve productivity and reduce costs. Since the agreement commenced, it has helped Vale Inco achieve the fastest ramp-up of all the companyâs greenfield sites in 2005; attain all-time production levels in 2006; achieve 1,000 days with no lost time due to injury in 2007; and reach the highest tonnes-per-day production in 2008.
ABB will continue its partnership with Iskueteu, an aboriginal company providing operations support, to fulfil the agreement. âABB Full Service agreements help turn maintenance departments into profit centres,â said Magnus Pousette, head of ABB Reliability Services North America. âBy bringing proven best reliability practices to our customers, we add new value to their bottom line while they focus on their core business.â
Vale Inco, a wholly-owned subsidiary of Vale of Brazil, is a leading producer of nickel, copper, cobalt and precious metals, based in Toronto, Canada. With over 100,000 employees worldwide, Vale is the second largest mining company in the world, with a market capitalisation of more than $125 billion.
KSB Pumps Inc. has announced the appointment of Reza Janirani as its
new Project Specialist for Western Canada. Janirani has over ten years
experience in the sales and application of pumps and related equipment.
He has also received extensive training at KSB Pumpsâ head office.
âIâm
very pleased to welcome Reza to our team,â says Michael Blundell,
President of KSB Pumps Inc. âWe have had considerable success in
Western Canada, supplying pumps for industrial and municipal
applications as well as the oil sands industry. Iâm confident that Reza
can help us continue to grow in this exciting and dynamic region.â
Janirani will support KSBâs operations from the global pump makerâs
Western Canadian office, located in the southern Calgaryâs Midpark
Court business centre, close to major engineering and consulting
companies. In addition to his sales and business development duties, he
will be responsible for maintaining the high level of support or KSBâs
distribution partners and customers. www.ksb.ca
MainTrain St. John's kicks off with predictive maintenance seminars
The first day of MainTrain
St. John's (Apirl 7 and 8) kicked off as a resounding success, filling
the conference hall at the local Delta St. Johnâs Hotel and Conference
Centre April 7 and bringing to the Martimes the first event of its kind.
As Canada's largest physical asset and maintenance management industry
association, the Plant Engineering and Maintenance Association of
Canada's (PEMAC)
Newfoundland chapter had an active hand in selecting and shaping the
content for this year's event to ensure it met the needs of local
industry.
Following opening remarks by PEMAC president Brian Malloch and
moderator John Lambert, from Benchmark Maintenance Services Inc.,
conference attendees were treated to a full day of technical training
seminars, which focused primarily on predictive maintenance tools like
thermography, oil analysis programs, ultrasound and laser alignment
systems. The theme of achieving a return on investment (ROI) was
prevalent throughout.
First up, Fluke Electronics Canada
industrial product manager Colin Plastow delivered a session on
thermography. For a complete rundown on the information covered in his
talk, check out our coverage and video of his talk last week in Toronto.
Plastow delved into the theory of infrared light and, most importantly,
material âemissivityâ â the relative ability of its surface to emit
infrared radiation. Different materials emit different levels of
infrared waves even if they are the same temperature, an important
distinction for a beginner, so they reviewed ways to work with those
limitations.
Darren German, Bosch Rexroth Canada hydraulics
business unit service manager, brought to everyone's attention the
important of a well-run oil analysis program â which is more than
filling a sample bottle with oil and sending it to a laboratory.
Considering the cost versus benefit, he says, oil analysis is one of
the best return on investment PdM practices available when executed in
a accurate, timely and consistent manner.
After lunch, the energetic Sean Miller, a certified Level I ultrasound inspector with UE Systems Inc.,
taught the audience about the latest in ultrasonic testing and tools.
To help highlight the technology's benefits, he presented "good" and
"bad" sounds measured from bearings, steam traps, pumps and other
common plant resources. Through various case studies, he presented ways
it can help save energy and, possibly more importantly, costs.
To cap off the full day of talks, Lambert discussed the importance of
proper up-front machinery installation, which is critical for all
maintenance departments. Unfortunately, he says, it isn't always done,
and the result is that machinery tends to fail prematurely. He reviewed
the ways to avoid incorrect alignment and the importance of employees
to be provided the correct tools and training to do their jobs right.
When
it comes to mounted bearing installation and maintenance, there are
many industry myths and misconceptions that may affect plant uptime and
overall performance. Maintenance managers need to be aware of these
elements, so that they can maximize performance and keep the plant
running.
Bearings can fail for many reasons and studies have helped to
understand the reasons for these failures. As shown in the pie chart
(click it to expand it), a large majority of bearing failures are
related to lubrication problems and contamination. The following myths
and misconceptions address some of these issues, and provide insight
into how they can be resolved and avoided.
Installation Myth #1:
Using a hammer is okay to position a bearing right?
FALSE: Never deliver a direct blow to a bearing. The rolling elements
and raceway are hardened, but they can still be damaged. Impact from
the hammer can transfer to the raceway leaving permanent indentations,
and running the bearing with these indentations can cause noise and
dramatically reduce bearing life. You should check the shaft diameter,
look for burrs, dirt or corrosion on the shaft and if needed use a
press to slide the bearing on. If a press is used, pressure should be
placed equally on the face of the inner ring to help avoid damage to
the raceways and rolling elements.
Installation Myth #2:
Off-the-shelf TGP shafting is always the best option.
FALSE: TGP is turned, ground and polished. It's a manufacturing method,
not a tolerance range or a guarantee that the shaft meets the bearing
manufacturer's specified range for diameter and roundness. It's
recommended to measure and specify the proper shaft diameter and review
the bearing manufacture recommendations.
Installation Myth #3:
It's okay to hand-tighten setscrews, one at a time.
FALSE: Setscrews are an integral part of the locking system between a
shaft and bearing, and should be tightened to the manufacturer's
recommend torque. Under tightening may result in loss of lock and
slipping of the bearing on the shaft, and over tightening may result in
raceway distortion or inner ring cracking. The recommended approach is
a half-full/full method. Half-full/full refers to tightening the first
setscrew to half the recommended torque, the second setscrew to the
full torque then back to the first setscrew for the full torque.
Lubrication Myth #1:
Re-lubrication once a year is sufficient.
FALSE: Re-lubrication is necessary to replenish grease in the bearing
when the current grease breaks down or deteriorates. Re-lubrication is
a necessity because the base oil breaks down as a result of
temperature. The lubrication film between the bearing rolling element
and the raceway can diminish or is eliminated, resulting in
metal-to-metal contact. Re-lubricating the bearing replenishes the oil,
helping maintain the proper lubrication film.
Pumping new grease into the bearing also helps flush away
contamination. Many mounted bearings are designed to allow the grease
to enter the bearing cavity as close to the rolling elements as
possible. As more and more grease is added to the bearing, the old
grease is pushed out of the seals (if the seals are purgeable). The
action of purging grease pushes and helps keeps dirt away from the
seals.
Bearing manufacturers offer general re-lubrication recommendations,
including amounts and intervals, as suggested starting points. The
amount of grease used at re-lubrication can vary with bearing size and
type. Re-lubrication intervals can vary based on load, speed
temperature, or environmental conditions. For example, a mounted ball
bearing in lightly loaded, low-speed, clean environments may only need
re-lubrication every 12 to 24 months.
However, each application is different and applications with higher
speeds, temperatures, or heavy contamination would require more
frequent bearing re-lubrication, possibly daily to once a week. Review
of the bearing manufacturer's recommendations is encouraged. Specific
applications should be monitored regularly and lubrication intervals
and amounts adjusted accordingly.
Lubrication Myth #2:
Always add grease until grease purges from the seal.
FALSE: If you pump grease into the bearing until it purges out the
seal, you likely have completely filled the bearing cavity. If you
completely fill the bearing with grease, the excess grease can increase
bearing operating temperature and potentially create enough pressure to
blow the seal out. However, in a dirty and/or low-speed application
where contamination may easily enter the seals, filling a bearing full
of grease may help improve bearing performance. Application experience
will dictate when the entire bearing cavity should be filled with
grease.
Lubrication Myth #3:
If there is noise, it must be the bearing and grease should be added.
FALSE: If the bearing is making noise, internal damage has likely
occurred. If the bearing continues to run without being replaced, more
internal damage may occur to the bearing, with the potential for
catastrophic failure. Adding grease may provide temporary relief, but a
noisy bearing should be closely monitored and replaced as quickly as
possible. The root of the failure should also be investigated either
with independent or manufacturer failure analysis (manufacturer
analysis requires removal of the bearing as soon as possible to aid in
a more accurate diagnosis of the problem).
Lubrication Myth #4:
Any grease will do.
FALSE: Not all types of grease are the same. Some grease can be
incompatible because of the different thickeners (soaps) used. When two
incompatible greases are mixed, they may thicken and harden or become
thin and leak out of the bearing. For example, many electric motors use
a polyurea thickener and some mounted ball bearings use lithium-complex
thickeners. This grease is borderline compatible, and depending upon
the final make up, may or may not work together. Grease types can also
be incompatible based on the viscosity or type of the oil in the
grease, so consulting with a lubrication supplier is always recommended.
Lubrication Myth #5:
Simply shoot grease through the grease fitting.
FALSE: Before putting grease into a system, it's recommended to fully
wipe the grease fitting and ensure that the grease gun is clean. One
good practice is to put the grease gun tip in an oil bath or wrap it
with a plastic cover to protect it.
Misapplication Myth #1:
Bearings will not be hot to the touch.
FALSE: Normal bearing operating temperatures can range from 80 degrees
to 150 degrees Fahrenheit, but certain applications may run higher or
lower than others. Most bearings are rated for -20 degrees to 220
degrees Fahrenheit, but can be supplied with special grease, seals or
heat stabilizing processes that allow them to operate at higher
temperatures.
Bearings typically run hotter at start up or right after re-lubrication
because excess grease increases drag and friction in the bearing. The
bearing will typically reach steady state operating conditions, as
excess grease is pushed out by the rolling elements and purged from the
seals. Spikes of up to 50 degrees Fahrenheit at start up and a spike of
30 degrees Fahrenheit can occur after re-lubrication.
Misapplication Myth #2:
Bigger bearings are always better.
FALSE: Bigger bearings have a higher load capacity, which may show a
higher bearing fatigue life. If the load isn't high enough to achieve
the minimum load requirement, however, the rolling elements can skid
along the raceway instead of roll. Skidding along the raceway may
result in high operating temperatures, excessive wear, lubrication
breakdown and subsequent bearing failures.
Misapplication Myth #3:
Sealed/lubed-for-life bearings will last forever.
FALSE: The bearing life will depend on the grease life, which is
affected by operating conditions (speed and load) and environment
(temperature and contamination). Various things can be done to improve
grease life, such as enhanced seals, proper installation practices and
proper grease selection. Ultimately, the best bearing is the properly
lubricated bearing.
If you have a bearing that doesn't achieve the desired bearing
operational life, consult a bearing manufacture that can assist in
properly selecting the bearing for the application.
This feature was previously published in REM
magazine. Ian A. Rubin is marketing manager, mounted bearings for
Sealmaster and Browning-branded products at Emerson Power Transmission
Solutions. For information, visit www.emerson-ept.com.
Matrikon selected to deliver real-time visualization intelligent oil field solution to Statoil
Edmonton, AB â Matrikon Inc., a leading provider of solutions for industrial intelligence, announced that it has been selected to build an intelligent oil field solution for Statoil's Norwegian well and production facilities including 35 off-shore assets in the North Sea with the possibility of international expansion following successful implementation in Norway. Statoil is one of the largest energy companies in the world.
Effective January 4, 2010, SpĂŠcialitĂŠ Hydraulique CĂ´te Nord, Inc. (SHCN) located in Sept-Iles, Quebec, was acquired by Wainbee Limited, a national leader in the distribution of fluid power and automation components and systems. As a result of this acquisition, Wainbee now has 13 locations coast-to-coast servicing customers from Vancouver to Halifax.
HOUSTON, TX â The Artificial Lift Company Ltd. (ALC), a leading artificial lift service company, announced on January 5th that its Rigless ESP solution developed in cooperation with ConocoPhillips has been approved by the operator for commercialization.
ALC has been working closely with ConocoPhillips for more than five years to develop its groundbreaking artificial lift solution for the oil and gas industry. The ALC RIGLESS ESP technology met the commercial terms of the contract with ConocoPhillips and passed the final acceptance test in September 2009.
The fully commercialized Rigless ESP system will undergo additional testing with ConocoPhillips in Q1 2010 in West Texas, and the first commercial installation for ConocoPhillips is scheduled for Q2/Q3 2010 in Alaska.
âArtificial Lift Company has been flexible and responsive to our specific needs, and provided us complete access in the technical development process,â said John Patterson, ConocoPhillips Production Engineering advisor. âWe believe ALCâs Rigless ESP technology is a cost-effective solution for companies facing challenging ESP applications with high intervention costs and in areas where securing a rig can require a long downtime. Our main driver for Alaska was to have a RIGLESS ESP system to allow replacement of sanded pumps and to clean out sand bridges in the casing below the ESP without using a rig.â
ALCâs Rigless ESP system significantly extends the life of a well and reduces maintenance costs.
âConocoPhillips has been great to work with in helping Artificial Lift to develop and commercialize the Rigless ESP artificial lift technology,â said ALC President Geoff Kimber-Smith. âThe commercialization of this technology will allow us to introduce the product to markets where there is real demand for alternative ESP solutions, especially in areas where work-over costs consume a large part of the budget. We believe that there will be many worldwide opportunities in key global regions as this system will radically change the costs incurred in deploying ESPs.â
Artificial Lift Company is a leading artificial lift service company based in the United Kingdom. To learn more, visit www.alcesp.com.
KSB Pumps Inc. has announced the appointment of Reza Janirani as its
new Project Specialist for Western Canada. Janirani has over ten years
experience in the sales and application of pumps and related equipment.
He has also received extensive training at KSB Pumpsâ head office.
The first day of 
When
it comes to mounted bearing installation and maintenance, there are
many industry myths and misconceptions that may affect plant uptime and
overall performance. Maintenance managers need to be aware of these
elements, so that they can maximize performance and keep the plant
running.
