Category: Uncategorized (Demo)

Main Advantages About Ceramic Bearings
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As important machinery parts, ceramic bearings have unmatched superior performances. Over the past decades, they have been increasingly widely used in many different industries such as aerospace, marine, nuclear industry, petroleum, chemical industry, textile industry, metallurgy, electric power, food, motorcycles, subway, and high-speed machine tools and so on. Their particular function is gradually recognized by people.

With the progress of the processing technology, costs of ceramic bearings have been declined. As in the past, they can only be used in some high-precision and advanced range of application areas. But now, they are gradually extended to various industries. Market prices of products are also gradually close to the practical situations. They are more acceptable to the users.

In recent years, research and development on ceramic bearings has yielded fruitful results and achieved substantive progress. They have been applied in machine tools, chemical industries, aerospace and many other fields. Obviously, they play a rather important part in the industries.

When compared to the steel bearings, these bearings have many specific advantages. Firstly, they have higher rotating speed and acceleration capacity. They can be operated under the conditions whose DN are more than 3 million. Meanwhile, they can reduce the possibility of slipping, wear and heating. Secondly, they have long service life and resistance to wear.

The fatigue life of full ceramic bearings is expected 10-50 times longer than steel bearings. Even the hybrid ceramic bearings have life span which is 3-5 times longer than the steel bearings. Thirdly, they require less lubrication. Because the coefficient of friction of ceramic materials is low, even the lubricant oil becomes thin; its lubricating ability is still as good as traditional lubricants on steel bearings. Fourthly, they are more corrosion-resistant.

Ceramic materials are inert materials and it is more resistant to corrosion and abrasion. Fifthly, they have high rigidity. Due to the high elastic modulus of the ceramic materials, the rigidity of bearings is 15-20% than the ordinary steel bearings. Sixthly, they can work under high temperature. Seventhly, their torque is low. According to the structure of ceramic bearings, their torque decreases by about 1 / 3. Eighthly, they are not magnetic and not conductive. They can avoid the damage of the magnetism and the electricity.

According to the above, we can safely draw the conclusion that ceramic bearings are increasingly important in our industries. With the development of the research and a large number of manufacturing technology breakthroughs, the application of ceramic bearings under the condition of high speed, high temperature will have very good prospects.

African Engineers: Green Cutlasses
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In an age in which Greens preach more loudly than Christians it is fitting that popular Biblical quotations find new green expressions. In Ghana, grassroots engineers have reinterpreted Isaiah’s vision of turning swords into ploughshares by turning worn out band-saw blades into farming cutlasses. Band-saws are used in Ghana’s numerous sawmills to turn its mighty forest trees into wooden planks, but making cutlasses from the old blades is helping small farmers to feed themselves and their village communities. Although this activity does nothing directly to preserve the forests it does recycle precious imported material and preserve it for use in a greener setting.

Band-saw blades are made of specially formulated carbon steel that combines the properties of hardness with flexibility and shock resistance. The metal can provide a sharp and durable cutting edge with the capability to run bent around steel rollers in a continuous loop. According to veterans of the sawmilling industry, all that these blades cannot survive is meeting a large rock that has been carried up by the tree as it grew and become embedded deep within its enormous trunk. Needless to say, steel of this quality is ideal for farmers’ cutlasses used for weed control and clearing scrub.

In informal industrial areas, or kokompes, like Suame Magazine in Kumasi, a cutlass maker’s workshop is identified by a pile of old band-saw blades lying nearby. The conversion process is really hard work. The material is so hard that it can be cut only by a hammer and chisel. The sharp cutting edge of the chisel can survive only a few blows before it needs re-sharpening and this is effected with the aid of an electric grinding machine, usually mounted on an old wooden bench. By this arduous process the outline of the cutlass blade emerges from the flat steel sheet of the old band-saw blade.

The shape of the cutlass blade includes the outline of the handle. Two holes are punched to allow a wooden handle to be held in place by rivets. The two wooden parts of the handle are usually made by a carpenter and supplied ready shaped to be fixed by the cutlass maker. With a wooden half-handle placed on each side of the steel blade, holes are drilled through the wood and the three-part sandwich is held firmly together by two steel rivets. The cutlass is finished by sharpening the cutting edge on the same grinding machine used for re-sharpening the chisel. When well crafted, as many of them are, the locally made cutlasses are of comparable appearance and effectiveness as imported models.

The high priests of the green movement would like to see the complete preservation of the tropical forests. This would entail the cessation of logging, the closure of sawmills and the eventual demise of the local grassroots cutlass industry. Ghana’s farmers would become dependent on imports, or local production based on imported material, for all of their cutlasses. No doubt, set against the larger green aspiration, this sacrifice would be easily made.

Carp Fishing Tackle Review: The Daiwa Windcast S-5000 Reel
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When you’re fishing for carp, you need your gear to be tough and reliable. For me, though, there’s a third criterion: price. There has to be a positive relationship between the cost of a reel and the way it performs. To be honest, I do enjoy stalking bargains almost as much as stalking the noble carp. Although I usually don’t opt for the lowest price, I shop carefully for carp fishing tackle that offers mid-priced bargains. Once reel I’ve recently discovered fits the bill quite nicely: the Daiwa Windcast S-5000.

Carp Fishing Tackle: Key Features of the Daiwa Windcast S-5000 Reel

Priced at about £99.99 on special offer, the Daiwa Windcast S-5000 reel is a great piece of carp fishing tackle. The reel has been redesigned, and has a higher level of performance, along with a new shape and updated look. If you’re looking for a reel that offers an ideal combination of speed and distance in casting, the S-5000 merits a serious look. Adaptable to many different fishing styles, this reel will quickly become a major ally in your hunt for the elusive carp. One feature I quickly noticed is that the spool is precisely tapered to release and deliver line at top speed.

Carp Fishing Tackle: More About the Daiwa Windcast S-5000 Reel

Still on the topic of line, I wanted to mention that the S-5000 has a HIP high impact line clip. There’s also a built-in cushion on the pin that gives the angler plenty of pinpoint casting accuracy. Anglers familiar with Daiwa reels will be glad to know that they’ve included all features we’ve come to expect from quality Daiwa reels, including AirBail, Twist Buster, DIGIGEAR, and Castlock. I particularly appreciate the AirBail feature, because it has a hollow tubular stainless steel bail that’s incredibly resistance to deformation. Digigear is Daiwa’s proprietary design process that ensures the perfect combination of the drive gear with the pinion gear. The drive gear is made from a surface treated, super-tough alloy, and the pinion gear is made from marine bronze. This gearing system makes the S-5000 an incredibly durable and powerful reel with plenty of speed. As fishing tackle goes, this is one reel I reach for often.

Carp Fishing Tackle: Final Thoughts on the Windcast S-5000

The S-5000 is a consistent best seller in Daiwa’s product range, and in fact broke sales records when it was launched. Daiwa’s marketing manager puts it thus: “The Windcast reel range has very quickly become our fastest selling big pit series ever. We had a brilliant reaction at trade shows from both dealers and press who have really taken to the range, so much so that we have had to increase our assembly of them.” This is one of my favourite pieces of carp fishing gear because it performs consistently. No surprises from this solidly built reel!

When shopping for top-quality carp fishing tackle, do be sure to consider the feature-packed Daiwa Windcast S-5000 reel.

Top 10 Gas Scooters
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Many manufacturers of gas scooters have come and gone in the past 10 years. It has become a very competitive industry; especially since the influx of cheaper Chinese brand clones entering the U.S. market. That being said, the quality gap between USA made and Chinese made scooters still heavily tilts in favor of the USA branded scooters. It is no surprise that 10 out of the 10 top gas scooters are all USA made scooters.

1. EVO 2X Powerboard

The Evo 2X is a third generation gas scooter from Puzey Design. The Evo brand powerboards are the highest quality products on the market and the fastest scooters ever built. The 2-speed gearbox is a patented, unique drive system that is the heart of the Evo 2X. It is the first two speed scooter in the world.

The range of applications of powerboards and scooters have thus far been limited by low revving, low horsepower engines. Now with the 2-speed gearbox, you can have the power when pulling off, or going uphill, in first gear and have the top speed with 2nd gear. Steep hill climbs for riders over 250lbs are no problem for the Evo 2X.

Another technological advancement found in the Evo 2X is the patented Cam-Link suspension. It is a true suspension system that offers a smooth ride, while offering excellent resistance when landing after jumps. Once you try it you will simply see there is nothing like it. This suspension is the strongest, most robust front suspension in the industry today.

The Evo 2X is one of the most reliable scooters ever produced. The steel and T6 aluminum frame are nearly indestructible. There have been reports of Evo scooters going 1300 miles without even replacing a belt.

Things you’ll never have to replace include:

The Frame and Suspension – Even though this scooter is largely designed with light weight aluminum, it is reinforced with steel where necessary. This makes the frame and structure of the scooter nearly indestructible.

The Engine – The Active 50 is not only an impressive power plant, it is also one of the most reliable engines available. A properly maintained engine which is run on 91+ octane fuel with a proper mix (1:40 – 1:50) will last the life of the scooter.

The Deck – The Evo 2X comes with one of the sturdiest decks available for a scooter. Although it is aluminum, it is unbelievably resilient to scratching and will never bend or crack.

2. Go-Ped GTR46i – Trail Ripper Interceptor

The Goped GTR Interceptor is an on-road, street racing version of the Goped GTR46 Trail Ripper. This high-performance Go-Ped now comes with the following modifications:

• New quieter exhaust system
• Smooth ride AT Primo Duro Trap aggressive treaded street tires
• Higher speed, better fuel economy
• Quieter GSR46R 6-76 sprocket drive ratio

These modifications make the Go-Ped GTR46i perfect for those that want to experience the fully suspended plush ride on paved and unpaved surfaces that comes only from the race proven and patented CIDLI suspension system. Dubbed C.I.D.L.I. for Cantilevered Independent Dynamic Linkless Indispension, this unique front and rear swing arm system is indispensable to this practical and fun light weight off-road machine.

3. Go-Ped Riot

The Go-Ped Riot was introduced along side the Go-Ped GTR46 as a pitbike like “scooter”. Like the GTR46, the Go-Ped Riot features front and rear CIDLI suspension.

Using the patented Trail Ripper adjustable suspension system in the front and rear, it offers riders great off-roading capabilities with 6″ of travel on each end. Powered by the powerful Go-Ped GP460RS engine geared at 6:98, the rugged and highly reliable Go-Ped Riot gives excellent bottom end and a stock top speed of 30mph. The centrifugal clutch provides for a very user friendly yet thrill-packed ride.

4. Martin Monster Beast

The Martin Monster Beast is the most powerful MMI production scooter available. It comes stock with a 52cc Mitsubishi engine which has almost twice the torque as the RC230 powered scooters. Each Beast is hand built by a single technician.

The frame uses the same dual suspension system Martin Monsters has become famous for. The frame is show chromed and hand polished. The drive chain is a robust 35 pitch heavy duty chain with a centrifugal clutch for easy stop-and-go use. The Beast is very powerful but also very quiet with tremendous reserves of power and torque. The Martin Monster Beast comes with an anti-vibration system for a very smooth vibration free ride. Many aftermarket performance parts are available to further customize your Beast.

5. Go-Ped GTR Roadster

The Goped GTR Roadster is an economy version of the Goped GTR46i. With the exception of the smaller Chung Yang GPL290 engine and welded T-bar handlebars, the GTR Roadster is the exact same scooter.

This cool scooter features the race proven, patented, adjustable and bullet proof GTR full 6″ CIDLI suspension frame. To that we’ve installed the incredibly light, yet powerful and quieter GPL290 engine with TT tires and sprocket drive ratios of the GSR Cruiser.

6. Martin Monster Super Shocker

The Martin Monster Super Shocker is a dual purpose machine equally at home, off road, or on. It comes with 10″ pneumatic knobby tires, to handle any terrain. The Super Shocker comes with a heavy duty automatic clutch which allows hands free stop-and-go operation.

This is the first and the best production scooter to use full suspension. The front suspension is telescoping motorcycle style and the rear is mono shock absorbing with up to 4″ of travel. A drilled front disk brake gives sure fast stopping. Power from the Martin Monster Super Shocker is by the Komatsu Zenoah RC230 engine with 2.5HP.

7. EVO 2 Powerboard

The Evo 2 is a third generation gas scooter from Puzey Design. The Evo brand powerboards are the highest quality products on the market and the fastest scooters ever built. The 2-speed gearbox is a patented, unique drive system that is the heart of the Evo 2X. It is the first two speed scooter in the world.

The Evo 2 is a high-performance, two speed scooter released as a more economical version of the Evo 2X. Unlike its big-brother, the Evo 2 does not have front suspension or a scrub board to protect the under-deck area. Rather than the impressive Active 50, the Evo 2 sports the milder Active 40 engine.

Since the Evo 2 does have the two speed transmission of the Evo 2X, it still does perform impressively despite the lack of performance in the Active 40 engine. If the Evo 2 is being used purely for transportation, the Active 40 will provide enough power along with the two speed transmission, but if any real speed is desired, an engine upgrade should be the first step.

That being said, the Evo 2 is one of the most reliable scooters ever produced

8. Go-Ped Super GSR46R

The Go-Ped GSR46R is one of the most powerful street scooters released by Go-Ped. It is intended to be a street-only scooter since it lacks any form of frame-based suspension. When it was released, the GSR46R, Go-Ped marketed it as the fastest production scooter in the world. Although the claim is debatable, it could very well have been true due to the high speeds attainable with the large R460 engine.

Developed on the legendary GSR40Tsi – Interceptor Go-Ped – the Super GSR46R is powered by the same motor as on the fearless Trail Ripper GTR46. Equipped with a patent pending centrifugal clutch chain drive mechanism geared at 6/76, the GP460RS engine delivers 4.2HP and 2.31 ft-lbs torque with a 17,500 redline, providing for excellent performance at low and high speeds. Tunable, it can even reach 5.5+ HP and 2.6+ ft-lbs of torque with the addition of an aftermarket expansion chamber.

The front and rear Mad Dog disc brakes provide excellent braking performance perfectly matched for the power output of the Go-Ped Super GSR46R.

All of Patmont Motor Werks finest racing components come standard: Heavy duty 4130 chromoly steel frame and double sided fork, pneumatic TT tires mounted with magnesium rims and 20″ Motorcycle style “Tim Patmont bend” racing handlebars fitted with a slide tube clamp, billet stem pro clamp, Go-Ped race pad and Pro control levers.

9. Martin Monster Moto

The Martin Monster Moto is a full suspension, chain driven scooter which inherited much of its design from its older brother, the Martin Monster Beast. The Moto’s advanced design features include such technical innovations as an anti-vibration system, which provides for a smooth vibration free ride. Other features include dual disk brakes, heavy duty chain drive, automatic clutch and front & rear suspension.

10. Go-Ped GSR Cruiser

The GSR Cruiser is the perfect machine for the customer wanting a quiet, reliable and economical motorized scooter with good performance, but also for beginners wanting an affordable, safe and easy to learn first scooter. PMW believes it is the perfect machine for a very large segment of motorized scooter enthusiasts.

The Go-Ped GSR Cruiser is also the perfect machine for motor heads and the after market community, as chassis upgrades and screaming engine mods are widely available. The GSR Cruiser’s power plant, the new GPL290, is based on the high performance GP290RS engine, designed to be a very reliable, quiet and economical cruiser. Top speeds for the GSR Cruiser are in the mid 20mph range, and its horse power is similar to the earlier GSR40.

Stopping power comes from the front Mad Dog brake caliper and double ground and hardened stainless steel Wave disc rotor. The rear brake mount is ready for the rear brake upgrade should the customer so choose to modify for more speed which needs more stopping power.

Welding Goggles Lens Materials
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Welding safety goggles are worn to protect the welder from shrapnel, ultraviolet, infrared light and bright light that can cause temporal or permanent blindness. The lens used in these safety goggles have to be hard coated and anti scratch. Anti-fog goggles would also be useful so that the wearer can have a clear view of the welding operation.

Many wonder how safety goggles differ from regular eye wear. The difference is that safety goggles have to conform to a standard, this standard is tabulated in the OSHA (occupational safety and health administration) 29CFR1910.133 (a)(5) eye and face protection. Also listed is the appropriate lens to go with specific welding operations.

The modern material of choice in protective lens manufacture is the polycarbonate lens. These lenses are tougher, thinner and lighter than regular plastic lenses. It is important that welding goggles be comfortable for the wearer and not too heavy so that the wearer is not blinded by excess sweat. The lightness and thinness of polycarbonate lenses provide this convenience without compromising on protection. They offer one hundred times more protection from the suns UV rays and are ten times more impact resistant than ordinary glasses.

Polycarbonate lenses were developed in the 1970’s for use in space related programs like visors on space suites and shuttle wind shields. In the early 80’s goggle lenses made of polycarbonate got introduced due to a demand for tougher and lighter lenses.

The primary properties of polycarbonate lenses are high impact resistance; a refractive index of 1.586 astm d 542; a haze of 1.0 astm d 1003; a light transmission 88% astm d 1003; and the ability to filter 99.9% of harmful radiation.

For the polycarbonate lenses to be used efficiently in welding goggles, they have to be hard coated to increase its impact resistance and treated to the appropriate shade to cope with the bright lights that emanates from and electric arc weld.

Glass protective lenses where the first to be used before the advent of the polycarbonate lens. The first glass lens goggles where those employed in a blast furnace, while this goggles provided protection from shrapnel is failed to give adequate protection from harmful radiation produce during welding. After a series of modification lenses were developed specifically for welding and these offered the desired protection needed.

Glass lenses have their limitations; some of the limitations are listed below.

• They are heavy and thick
• They are expensive in comparison to the polycarbonate lenses
• Scratch proofing the lenses are expensive
• Have lower impact strength than polycarbonate lenses.

Nylon is a tough material used in lens manufacture. It is characterised by its ability to absorb moisture which gives it a very high impact resistance. Nylon lenses also have a high thermal resistance and are scratch resistant.

All materials used in protective welding goggle lenses must be subject to rigorous tests. The OSHA (occupational safety and health administration) and the ANSI (American national standards institute) offer a standard for testing and grading of the lenses.

YLC-6M Radar Technical System
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The Reflector antennas of YLC-6M radar “2D radar” can achieve the best electric performances ever, such as low side lobe “maximum side lobe level less than or equal -30dB, An average side lobe level less than or equal -40dB”, higher gain, lighter weight, and suitable environment adaptability “without Dew effects like planar array Radome”. Moreover, it can provide a high full cycle efficiency/cost ratio.

In YLC-6M radar, it’s assembled together with three blocks. At the transportation state, the middle block lies back onto the roof of the transmitter cabin, when the two edge blocks are disassembled with one on each side of the transmitter cabin. Notwithstanding, it’s assured that the radar system can’t go beyond the limit of the transportation height when it’s transported. The use of Quincunx Hollow reflector antenna not only can meet the requirements for Hyperboloid accuracy; nevertheless, can reduce weight and decrease wind resistance to allow the radar operates in the more severer environment. It is unnecessary to pack the Radome on the reflector antenna; accordingly, the environmental factors, such as temperature, humidity, etc.

YLC-6M radar is a medium/low altitude, 2D radar system. In beam design, it takes a full consideration of radar’s low altitude performance, also ground clutter rejection capability; therefore, a combination of a high & low beam is used:
– The low beam is a common beam for both transmitting and receiving. Its elevation is 2.7 degrees, furthermore, used for the detection of long-range targets.

– The high beam is a beam only for receiving. Its elevation is 7 degrees. It can be used to reject the strong ground clutter effectively! Ordinarily, used for the detection of short-range targets or targets just above the head.

YLC-6M radar is a highly mobile medium/low altitude surveillance radar, with different operating ranges; consequently, can detect short-range air targets. Wherefore a various signals are designed, among which the signal with pulse duration of 100 ms (microsecond) is used for the detection of long-range targets. However, It can result in the corresponding short-range blind area. Consequently, an additional carrier frequency signal with pulse duration of 0.8 ms is transmitted within every PRI (Primary Rate Interface) for range blind area compensation. The signal with pulse duration of 100 ms is a non-linear FM rectangular pulse signal. Its echo is compressed into a signal of 0.8 ms by a digital matching filter, so that both: The radar detection coverage, also the high range resolution can be achieved without using higher transmitted power. The use of lower radar transmitted power allows not only the decrease of radar-intercepted probability, but the increase of radar’s anti-reconnaissance capability too. As well it provides the conditions for the modular design of radar solid state transmitters.

END OF PART II

Overcoming Sewing Motor Weakness Disorder
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Most of us, live our lives with certain expectations.

We expect the light to turn on when we turn the switch. We expect our cars to go when we press down on the accelerator.

So, when we press down on the foot control of our sewing machines we expect the sewing machine to work.

At times, we get to thinking of your sewing machine like a friend or in a sense like a real person. We talk to it. We touch it. We listen to it. Sometimes, it may appear that our friend is stricken with an infection or disease. This is especially true when we press down on the power and very little happens.

When you press down on your foot control, does your sewing machine hesitate? Does it groan a little? Does it turn ever so slowly or maybe not at all?

If so, then your sewing machine may have the dreaded Sewing Machine Motor Fatigue Syndrome..

You can determine if this is your problem fairly quickly with a few basic tests.

You set up your sewing machine and are ready to sew, but when you press down on the foot pedal the machine barely moves at all. It is as though the machine is tired from a long hard summer. No matter how hard you press down on that foot control; no matter how much power you put in; the sewing machine just drags along.

The two most common sources of such a problem are the potential for a bind in the sewing machine mechanism itself and problems in the motor.

To check for binding, turn the hand wheel by hand and feel for any undue resistance. If the machine is stiff, your problem may be the mechanism. If the machine moves freely, it is probably a problem with the motor.

The AC motor in your sewing machine or mounted behind the head of your machine, will often accumulate debris inside. This debris may consist of partially burned carbon deposits, dust and dirt, and old lubricants. Gradually, this debris takes its toll on the operation of the motor.

You do not need to be an expert on motors, to understand how deposits of debris can make it more and more difficult for the motor to perform as expected. Over time, the motor loses its ability to work properly and may even fail to turn at all.

One solution to this problem is to remove the deposits by actually burning them away. By running the motor at full throttle for several minutes, it is often possible to do just that.

Follow this procedure: In the center of the hand wheel is a break that causes the machine to turn when the hand wheel turns. Release it so the hand wheel moves freely without turning the machine. Hold down the power pedal using by hand or use a clamp or weight to hold it down. The motor should slowly begin to turn. If not carefully turn the hand wheel while applying electricity to the motor to help the motor turn. Once the motor is turning, Keep it turning at full speed for about five minutes. Allow it to cool and test it again.

Attend the machine as long as you have it going. Watch out for extreme heat, sparks, or smoke from the motor.

The motor burn is often very effective in burning off the old carbon deposits, debris, and gunk. Essentially, you are heating up the motor to melt away and burn away the debris. In the process, you may find that the motor gets overly hot, excessive smoke begins billowing from the motor, or sparks may fly from it. Be very careful not to let these become problematic. Shut down anytime you sense, the burn is getting out of control.

In some cases, the motor burn does not work. The damage to the motor is too extensive. In such cases, you may remove the motor brushes and replace them. You may disassemble the motor housing and clean away the gunk from the contact points and armature. If you do so, beware. Using solvents in electrical appliances can be extremely dangerous. Before applying electricity to any motor make certain it is 100% dry and free of anything that might ignite, smolder, or otherwise cause harm.

Usually, you can fix the Sewing Machine Motor Fatigue Syndrome with a ten minute motor burn or service.

Guidelines For Performing Infrared Inspections Of Motor Control Centers
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The Motor Control Center

The MCC enclosure protects personnel from contact with current carrying devices, and it protects the components from various environmental conditions. It is important that the enclosure is mounted to assure accessibility so that qualified personnel (such as a trained thermographer) can open the panel under load. There are different classes and types of MCCs, but generally speaking, an MCC looks like a row of file cabinets with each cabinet representing an MCC section. The drawers of the file cabinet represent the plug-in units that contain the motor control components. Three phase power is distributed within the MCC by bus bars, large metal current carrying bars. The horizontal bus provides three-phase power distribution from the main power supply. Vertical bus in each section is connected from it to individual MCCs. Bracing and isolation barriers are provided to protect against fault conditions. The plug-in units of an MCC have power stabs on the back to allow it to be plugged into the vertical power bus bars of the structure.

Beginning Your MCC Infrared Inspection

Before opening the panel or door on a motor controller, prescan the enclosure to assure a safe opening condition. If excessive heat appears on the surface of the door, extra care should be taken when opening it. The thermographer or escort may decide to note the condition as unacceptable and not take a chance on opening it under load. Once the unit is open, begin with both an infrared and a visual inspection to assure no dangerous conditions exist. Be systematic while conducting the infrared inspection. Remember the system must be under load to conduct the inspection. Work from left to right or follow the circuit through carefully, inspecting all of the components. Look for abnormal thermal patterns caused by high-resistance connections, overloads, or load imbalances. In three-phase systems this can be accomplished by comparing phases. Adjust the level and span on the infrared system to optimize the image. Proper adjustment will identify primary and secondary anomalies. The bus stabs and the connections to the main are important inspection points that are often overlooked or misdiagnosed. The incoming connection to the main horizontal bus is usually located behind a cover or panel that is not hinged. These are typically bolted connections and may have parallel feeders. The bus stab connections on the back of the plug-in units are more difficult to inspect. The thermographer does not have direct view of the connection, and the first indication of a problem can be seen on the incoming conductors feeding the breaker or fused disconnect. Remember, even small temperature rises identified at this point could mean serious problems.

Motor Starters and Motor Controllers

The purpose of the motor starter is to protect the motor, personnel, and associated equipment. Over 90% of the motors used are AC induction motors, and motor starters are used to start and stop them. A more generic term would identify this piece of equipment as a motor controller. A controller may include several functions, such as starting, stopping, overcurrent protection, overload protection, reversing, and braking. The motor starter is selected to match the voltage and horsepower of the system. Other factors used to select the starter include: motor speed, torque, full load current (FLC), service factor (SF), and time rating (10 or 20 seconds).

Understanding the thermal patterns of this equipment is critical to a successful inspection. Also correctly identifying the source of the anomaly can make recommendations more valuable.

Motors may be damaged or their life significantly reduced if they operate continuously at a current above full load current. Motors are designed to handle in-rush or locked rotor currents without much temperature increase, providing there is a limited duration and a limited number of starts. Overcurrents up to locked rotor current are generally caused by mechanical overloading of the motor. The National Electric Code (NEC) describes overcurrent protection for this situation as “motor running overcurrent (overload) protection.” This can be shortened to overload protection. Overcurrents caused by short circuits or ground faults are dramatically higher than those caused by mechanical overloads or excessive starts. The NEC describes this type of overcurrent protection as “motor branch-circuit short-circuit and ground-fault protection.” This can be shortened to overcurrent protection. The four common varieties of motor starters are: across-the-line, the reversing starter, the multispeed starter, and the reduced voltage starter. Motor starters are generally comprised of the same types of components. These include a breaker or fused disconnect, contactor and overloads. There may also be additional components, including control circuitry and a transformer. Understanding the thermal patterns of this equipment is critical to a successful inspection. Also correctly identifying the source of the anomaly can make recommendations more valuable.

Overcurrent Protection

NEC requires overcurrent protection and a means to disconnect the motor and controller from line voltage. Fused disconnects or thermal magnetic circuit breakers are typically used for overcurrent protection and to provide a disconnect for the circuit. A circuit breaker is defined in NEMA standards as a device designed to open and close a circuit by non-automatic means and to open the circuit automatically on a predetermined overcurrent without injury to itself when properly applied within its rating. If we look at a cutaway of a breaker, we can identify potential connection problems. The line side and load side lugs are the most common source of abnormal heating, but many breakers have a second set of bolted connections on the back of the breaker. Heat from this connection can be misdiagnosed as the main lug. There are also internal contacts where current flow is interrupted by exercising the component. These contacts experience arcing each time the breaker is opened. An arc is a discharge of electric current jumping across an air gap between two contacts. Arcs are formed when the contacts of a circuit breaker are opened under a load. Arcing under normal loading is very small compared to an arc formed from a short circuit interruption. Arcing produces additional heat and can damage the contact surfaces. Damaged contacts can cause resistive heating. Thermal patterns from these poor connections appear as diffuse heating on the surface of the breaker. In addition, there are several types of breakers that have internal coils used for circuit protection. These coils have heat associated with them and can appear to be an internal heating problem, when in fact, it is a normal condition.

Fused Disconnects

Fused disconnects are used to provide over-current protection for motor in the same manner as a breaker. Instead of opening contacts, fuses fail opening the circuit. When overcurrent protection is provided by fuses, a disconnect switch is required for manual opening of the circuit. The disconnect switch and fuse block are typically one assembly. The hinge and blade connections on the switch are a typical source of overheating. High resistance from overuse or underuse is usually the cause. Fuse clips are also a weak connection point for some disconnect designs. Different types or manufacturers of fuses of the same amperage may produce different thermal signatures. While different size or amperage fuses will also have a different thermal pattern, fuse bodies may appear warmer than the rest of the circuit due to conductor size.

Contactors

Starters are made from two building blocks, contactors and overload protection. Contactors control the electric current flow to the motor. Their function is to repeatedly establish and interrupt an electrical power circuit. A contactor can stand on its own as a power control device, or as part of a starter. Contactors operate electromechanically and use a small control current to open and close the circuit. The electromechanical components do the work, not the human hand, as is the case with a knife blade switch or a manual controller. The sequence of operation of a contactor is as follows: first, a control current is applied to the coil; next, current flow into the coil creates a magnetic field which magnetizes the E-frame making it an electromagnet; finally, the electromagnet draws the armature towards it, closing the contacts. A contactor has a life expectancy. If the contactor contacts are frequently opened and closed, it will shorten the life of the unit. As the contacts are exercised, an electrical arc is created between the contacts. Arcs produce heat, which can damage the contacts. Contacts eventually become oxidized with a black deposit. This black deposit may actually improve the electrical connection between the contacts by improving the seat, but burn marks, pitting, and corrosion indicate it is time to replace the contacts. The following thermal patterns are associated with contactors. The coil of the contactor is usually the warmest part of the unit. High temperatures may indicate a breakdown of the coil. Line side and load side lug connections may show high resistance heating from poor connections. Heating from burned and pitted contacts may be thermally “visible” on the body of the contactor.

Overload Protection

The ideal motor overload protection is a unit with current sensing capabilities similar to the heating curve of the motor. It would open the motor circuit when full load current is exceeded. Operation of this device would allow the motor to operate with harmless temporary overloads, but open up when an overload lasts too long.

Typical thermal problems in overloads are found in the connections to the contactor, overload relay, or motor.

This protection can be provided by the use of an overload relay. The overload relay limits the amount of current drawn to protect the motor from overheating. It consists of a current sensing unit and a mechanism to open the circuit. An overload relay is renewable and can work for repeated trip and reset cycles. Overloads, however, do not provide short circuit protection. The melting alloy (or eutectic) overload relay consists of a heater coil, a eutectic alloy, and a mechanical mechanism to activate a tripping device when an overload occurs. The relay measures the temperature of the motor by monitoring the amount of current being drawn. This is done indirectly through a heater coil, which under overload conditions, melts a special solder allowing a ratchet wheel to spin free and open the contact. A bimetallic thermal overload uses a U-shaped bimetal strip. In an overload condition heat will cause the bimetal to deflect and open a contact. The solid state overload relay does not generate heat to cause a trip. Instead, it measures current or a change in resistance. The advantage of this method is that the overload relay doesn’t waste energy generating heat and doesn’t add to the cooling requirements of the panel. Normal heating for an overload may look like a thermal anomaly. Heat generated in the coil or bimetal may look like a connection problem. Typical thermal problems in overloads are found in the connections to the contactor, overload relay, or motor.

Starters

Starters are the combination of a controller, usually a contactor and an overload relay. The above descriptions of the individual components apply to the starter systems. Reduced voltage starters are used in applications that involve large horsepower motors. They are used to reduce the in-rush current and limit the torque, and thus the mechanical stress on the load. The components of this type of starter should be inspected as the motor steps up to speed. A separate low-voltage starter circuit is used to step the motor up to speed. Once at operating speed, these components are de-energized.

Completing Inspections

Remember that primary anomalies are the problems that readily stand out while secondary anomalies may require that primary anomalies be adjusted into saturation to allow for the identification of a secondary anomaly. For example, different fuse types and sizes will cause different thermal signatures as will overload relays that are sized differently within the same circuit. Anomalies like this should be identified and reported. Also note that when evaluating the severity of a problem, temperature is just one variable. All of the parameters involved with the severity of the anomaly should be considered. To improve temperature measurements, avoid low emissive surfaces. Look for cavity radiators or highly emissive insulation on conductors. Measure loads where component sizing, overloading, or load imbalances are observed. Beware of the effects of wind or convection on components. Note ambient temperatures, large thermal gradients, and the source of heating. Safety should be the top consideration.

Conclusion

Knowing the equipment under inspection allows for the correct identification of problems that could be misdiagnosed or overlooked. Analyzing unfamiliar thermal patterns on a component is easier when equipment design is reviewed. More precise repair recommendations can also be made. Locating temperature differences qualitatively or quantitatively is the real benefit of infrared thermography. Knowing where to look for these temperature differences comes from knowledge of the equipment, and knowledge of the equipment will make a better thermographer.

Compression Springs – Technical Specifications of the Product
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Compression springs are relevant when the main purpose of a person or a business is to go up against the axis of the wind during the process of compression. They have different forms including straight and conical and can be constructed out of stacked elements. The variable diameters of the inner and outer parts as well as the wire of the compression spring should be used in order to make a purchase.

Compression springs are made out of different materials including high carbon steel wire, stainless steel, music wire, alloy steel, nickel-based alloy wire and brass. These parts are used in order to make sure that the springs will be able to resist corrosion. Some of the materials are also favored for their costs and elastic capabilities. Learn about the other technical aspects of these industrial products.

Physical and chemical properties of springs

Springs are commonly made with a wide array of materials. Despite this however, the product should be made from high quality items and not just any forms of alloy in the market. High strength alloys are recommended to ensure that the product will comply well with strength requirements. Overall, the spring should be a combination of high elastic limits, low modulus and high strength properties.

Since springs are expected to perform a lot of activities, they should cover a very extensive range when it comes to elasticity. It is therefore important to focus on the magnetic permeability, corrosion resistance, formability, fatigue strength, electric conductivity and availability as physical properties of the springs.

One important factor to look into when it comes to manufacture of compression springs is surface quality. This factor influences the capability of the spring to withstand fatigue strength. It is best to seek materials that are of the best surface quality to comply with high cycle regions.

Designs of springs

When spring designs are considered, the elastic modulus in terms of shear and tension is brought to mind. A modulus is a physics coefficient used to express the degree to which a substance shows a particular property or characteristic. The modulus is often a variety of the chemical composition as well as the degree of aging and cold work on the spring.

If the compression springs do not comply with the requirements, small technical variations may be made. The variation is adjusted in conjunction with certain parameters of the design including the coil diameter and the number of active coils. When material selection for the spring is a huge concern, the operating environment should be highly regarded.

Steel and Wood Lathe Chisels
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This article discusses a few types of steel that many wood lathe chisels are made from. There are many different types of steel alloys with a verity of hardness’ and strength. The internet has a huge amount of information on steel, alloys and their use, a little research will always lead to better understanding of the tools you want to buy or make.

What is tool steel and what makes it different that other types of steel? Tool Steel is a specific type of high quality steel made specifically for the production of tools and tooling components. Tool steels are produced in electric melt furnaces and stringent quality standards are upheld to produce the necessary quality. Tool steels are formulated to withstand high pressures and abrasive materials. Typically tool steels are used for shearing, cutting, stamping, and forming of metals and plastics.

There are 3 different tool steels that you will most commonly see associated with wood turning tools, they are 01 steel, M2 steel and PM steel.

O1 tool steel is a low alloy cold work tool steel that must be oil-quenched in heat treatment to create the required hardness. O1 contains small amounts of manganese, tungsten, and chromium, giving O1 adequate toughness for normal tool & die uses. 01 steel is a steel that wood turners can use to make and shape their own tools and then temper the steel to a hardness that will hold a good edge some where between 60 to 65 HRC.

M2 is a higher carbon version of the M1 tool steel (Molybdenum High Speed Tool Steel). The M2 alloy has somewhat better wear resistance than M1. Applications are primarily used for cutting tools and shaping.

PM (Powder metallurgy) is a term covering a wide range of ways in which materials or components are made from metal powders Powder metallurgy is also used to make unique materials impossible to melt or form in other ways. PM Wood Lathe tools are very hard and hold a fine edge usually some where between 67 to 69 HRC. Files will not work on tools of this hardness. HRC is an abbreviation for Rockwell Hardness measured on the C scale.

If you are turning wood on a regular basis you probably have 30 to 40 tools that you use. I Counted the Wood Turning Tools in my collection and there are currently 43 and I am ordering some 01 steel to make Scrapers that I can use to shape long even sides of a turning. The 01 steel allows you the ability to make your own tools, especially tools that fit a specialty turning that only you are doing. It is always good to have a friend who is a metal worker and understands how to machine and temper metals.

There are many ways to acquire wood lathe tools. Buying from a tool supplies is the best way to start wood turning. With a little experience you will know what to look for when acquiring tools. Aside from buying from a tool supplier, watch the garage sales, estate sales and some of the social sites like Craigslist..

Wood turning is fun and enjoyable and even more so when you are able to make you own tools.