History Of Power Frequency

Many different power frequencies were used in the 19th century. Very early isolated AC generating schemes used arbitrary frequencies based on convenience for steam engine, water turbine and electrical generator design. Frequencies between 16⅔ Hz and 133⅓ Hz were used on different systems. For example, the city of Coventry, England, in 1895 had a unique 87 Hz single-phase distribution system that was in use until 1906. The proliferation of frequencies grew out of the rapid development of electrical machines in the period 1880 through 1900. In the early incandescent lighting period, single-phase AC was common and typical generators were 8-pole machines operated at 2000 RPM, giving a frequency of 133 cycles per second.

Though many theories exist, and quite a few entertaining urban legends, there is little certitude in the details of the history of 60 Hz vs 50 Hz.

The German company AEG (descended from a company founded by Edison in Germany) built the first German generating facility to run at 50 Hz, allegedly because 60 was not a preferred number. AEG's choice of 50 Hz is thought by some to relate to a more "metric-friendly" number than 60. At the time, AEG had a virtual monopoly and their standard spread to the rest of Europe. After observing flicker of lamps operated by the 40 Hz power transmitted by the Lauffen-Frankfurt link in 1891, AEG raised their standard frequency to 50 Hz in 1891.

Westinghouse Electric decided to standardize on a lower frequency to permit operation of both electric lighting and induction motors on the same generating system. Although 50 Hz was suitable for both, in 1890 Westinghouse considered that existing arc-lighting equipment operated slightly better on 60 Hz, and so that frequency was chosen.[5] Frequencies much below 50 Hz gave noticeable flicker of arc or incandescent lighting. The operation of Tesla's induction motor required a lower frequency than the 133 Hz common for lighting systems in 1890. In 1893 General Electric Corporation, which was affiliated with AEG in Germany, built a generating project at Mill Creek, California using 50 Hz, but changed to 60 Hz a year later to maintain market share with the Westinghouse standard.

 

25 Hz origins

 The first generators at the Niagara Falls project, built by Westinghouse in 1895, were 25 Hz because the turbine speed had already been set before alternating current power transmission had been definitively selected. Westinghouse would have selected a low frequency of 30 Hz to drive motor loads, but the turbines for the project had already been specified at 250 RPM. The machines could have been made to deliver 16⅔Hz power suitable for heavy commutator-type motors but the Westinghouse company objected that this would be undesirable for lighting, and suggested 33⅓ Hz. Eventually a compromise of 25 Hz, with 12 pole 250 RPM generators, was chosen. Because the Niagara project was so influential on electric power systems design, 25 Hz prevailed as the North American standard for low-frequency AC.

40 Hz origins

 A General Electric study concluded that 40 Hz would have been a good compromise between lighting, motor, and transmission needs, given the materials and equipment available in the first quarter of the 20th Century. Several 40 Hz systems were built. The Lauffen-Frankfurt demonstration used 40 Hz to transmit power 175 km in 1891. A large interconnected 40 Hz network existed in north-east England (the Newcastle-upon-Tyne Electric Supply Company, NESCO) until the advent of the National Grid (UK) in the late 1920s, and projects in Italy used 42 Hz. The oldest continuously-operating commercial hydroelectric power plant in the United States, at Mechanicville, New York, still produces electric power at 40 Hz and supplies power to the local 60 Hz transmission system through frequency changers. Industrial plants and mines in North America and Australia sometimes were built with 40 Hz electrical systems which were maintained until too uneconomic to continue. Although frequencies near 40 Hz found much commercial use, these were bypassed by standardized frequencies of 25, 50 and 60 Hz preferred by higher volume equipment manufacturers.

Standardization

 In the early days of electrification, so many frequencies were used that no one value prevailed (London in 1918 had 10 different frequencies). As the 20th century continued, more power was produced at 60 Hz (North America) or 50 Hz (Europe and most of Asia). Standardization allowed international trade in electrical equipment. Much later, the use of standard frequencies allowed interconection of power grids. It wasn't until after World War II with the advent of affordable electrical consumer goods that more uniform standards were enacted.

In Britain, implementation of the National Grid starting in 1926 compelled the standardization of frequencies among the many interconnected electrical service providers. The 50 Hz standard was completely established only after World War II.

Because of the cost of conversion, some parts of the distribution system may continue to operate on original frequencies even after a new frequency is chosen. 25 Hz power was used in Ontario, Quebec, the northern USA, and for railway electrification. In the 1950s, many 25 Hz systems, from the generators right through to household appliances, were converted and standardized. Some 25 Hz generators still exist at the Beck 1 and Rankine generating stations near Niagara Falls to provide power for large industrial customers who did not want to replace existing equipment; and some 25 Hz motors and a 25 Hz electrical generator power station exist in New Orleans for floodwater pumps. Some of the metre gauge railway lines in Switzerland operate at 16⅔ Hz, which can obtained from the local 50 Hz 3 phase power grid through frequency converters.

In some cases, where most load was to be railway or motor loads, it was considered economic to generate power at 25 Hz and install rotary converters for 60 Hz distribution.Converters for production of DC from alternating current were larger and more efficient at 25 Hz compared with 60 Hz. Remnant fragments of older systems may be tied to the standard frequency system via a rotary converter or static inverter frequency changer. These allow energy to be interchanged between two power networks at different frequencies, but the systems are large, costly, and consume some energy in operation.

Rotating-machine frequency changers used to convert between 25 Hz and 60 Hz systems were awkward to design; a 60 Hz machine with 24 poles would turn at the same speed as a 25 Hz machine with 10 poles, making the machines large, slow-speed and expensive. A ratio of 60/30 would have simplified these designs, but the installed base at 25 Hz was too large to be economically opposed.

In the United States, the Southern California Edison company had standardized on 50 Hz. Much of Southern California operated on 50 Hz and did not completely change frequency of their generators and customer equipment to 60 Hz until around 1948. Some projects by the Au Sable Electric Company used 30 Hz at transmission voltages up to 110,000 volts in 1914.

In Mexico, areas operating on 50 Hz grid were converted during the 1970s, uniting the country under 60 Hz.

In Japan, the western part of the country (Kyoto and west) uses 60 Hz and the eastern part (Tokyo and east) uses 50 Hz. This originates in the first purchases of generators from AEG in 1895, installed for Tokyo, and General Electric in 1896, installed in Osaka.

Utility Frequencies in Use in 1897 in North America

Cycles Description

140 Wood arc-lighting dynamo

133 Stanley-Kelly Company

125 General Electric single-phase

66.7 Stanley-Kelly company

62.5 General Electric "monocyclic"

60 Many manufacturers, becoming "increasing common" in 1897

58.3 General Electric Lachine Rapids

40 General Electric

33 General Electric at Portland Oregon for rotary converters

27 Crocker-Wheeler for calcium carbide furnaces

25 Westinghouse Niagara Falls 2-phase - for operating motors

Even by the middle of the 20th century, utility frequencies were still not entirely standardized at the now-common 50 Hz or 60 Hz. In 1946, a reference manual for designers of radio equipment listed the following now obsolete frequencies as in use. Many of these regions also had 50 cycle, 60 cycle or direct current supplies.

Frequencies in Use in 1946 (As well as 50 Hz and 60 Hz)

Cycles Region

25 Canada (Southern Ontario), Panama Canal Zone(*), France, Germany, Sweden, UK, China, Hawaii,India, Manchuria,

40 Jamaica, Belgium, Switzerland, UK, Federated Malay States, Egypt, West Australia(*)

42 Czechoslovakia, Hungary, Italy, Monaco(*), Portugal, Romania, Yugoslavia, Libya (Tripoli)

43 Argentina

45 Italy, Libya (Tripoli)

76 Gibraltar(*)

100 Malta(*), British East Africa

Where regions are marked (*), this is the only utility frequency shown for that region.

New Scooter 2009 Yamaha T-Max Review

2009 Yamaha T-Max

It seems abandoned bygone that Yamaha presented its aboriginal maxi-scooter which signalled a about-face in the European scooter market. And yet eight years accept passed, with the admission accepting occurred aback in July 2000.

 2009 Yamaha T-Max

This is abundant added than a simple scooter - adequate and spacious, it additionally has the active amusement and accordance of a abate scooter. This has fabricated the Yamaha T-Max a bazaar success, agreement it in the top ten of bikes awash with 23,000 units in the aboriginal eight months of 2008. A acceptable 15,000 of these were awash in Italy alone.

 2009 Yamaha T-Max

With affairs for aerial appeal in 2009, the allegorical chicken colour “extreme yellow” is available. This is an about agitated livery, but if you appetite article added bass bottomward there is additionally Midnight Black, Silver Aerial Tech and Stealth Metal. Pricing for 2009 is already available, including the ABS option.

Suzuki Skywave 125 Low Rider Modification

 Suzuki Skywave 125 Low Rider Modification admiration is absolutely normal. Or arguably obsolete. That's because the changes fabricated to the arbor with bound arena still maintains the standards body. 

 Especially for the time being, those who formed on the affectation has a lot of low addition with a abundant anatomy custom. So, if there is feel abundant to comedy with the accepted body, it absolutely has not cuy season.

Suzuki Skywave 125 low addition admiration is absolutely normal. Or arguably obsolete. That's because the changes fabricated to the arbor with bound arena still maintains the standards body. 

Especially for the time being, those who formed on the affectation has a lot of low addition with a abundant anatomy custom. So, if there is feel abundant to comedy with the accepted body, it absolutely was not the division cuy Eg for business rim. Anton not rim abrasion market. "I fabricated myself with apropos to a association archetypal Harley-Davidson (HD). Certainly this archetypal is actual rare," added the man this tasseled. 

 Although the admeasurement of the approach of a rim is not too wide, but with a specific anatomy of advance accept the power. "Especially with accurate finishing and blanket nickel, appropriately the rim is so actual classy," adds Anton. Oh yes, for the position of the rear auto had aloof 25 cm compared to the antecedent conditions.

 It's the aforementioned with the bankrupt and handlebars. "Basically I appetite to attending simple but absolutely absolutely point," said Erwin Dwi motorcycle buyer chimed.

 Long, beeline bankrupt archetypal is to be able a affair that additionally has a ample influence. Bankrupt and council was absolutely the assignment of Anton. "These two genitalia additionally fit the affair of low rider," added this angular guy.

 For the body, it alone makes sepatbor Anton advanced and rear. But, do not booty agilely the access of this sepatbor. By allotment an adapted model, again it could accomplish this Skywave be so actual low rider.

 Anton akses aftereffect proves that consequence with a simple but absolute accord and detail it will attending attractive.

 For business blush and Anton Erwin agreed to use beginning or blush they anticipate is fresh. "Therefore we accept the blush green, but a apparent baseball," Erwin said that to leave the painting to the branch on FIM two handyman, South Jakarta.

 But absolutely not aloof green. Clear airbrush blow additionally required. "This way alike if the anatomy is still the accepted but it looks like customed," added Erwin.

 Who agreed motive was added appear the called graphic. Simple archetypal with furnishings boxes. "The motive is accustomed sepatbor advanced and rear. And abutting to the rear of the body," he added.

The beheading archetypal of the aftereffect is not as simple boxes that shadowed.Karena with a appropriate address so that it looks as if the motive in three dimensions.

 DATA MODIFICATION Suzuki Skywave 125 Low Rider:

 Front rim: Custom 5x14 inches

 Front tire: 140/60-14 Swallow

 Rear rim: Custom 7x14 inches

 Rear tire: 160/60-14 Swallow

AC Motor Construction

Three-phase AC induction motors are commonly used in industrial applications. This type of motor has three main parts, rotor, stator, and enclosure. The stator and rotor do the work, and the enclosure protects the stator and rotor.

Stator Core

The stator is the stationary part of the motor’s electromagnetic circuit. The stator core is made up of many thin metal sheets, called laminations. Laminations are used to reduce energy loses that would result if a solid core were used.

Stator Windings Stator laminations are stacked together forming a hollow cylinder. Coils of insulated wire are inserted into slots of the stator core.

When the assembled motor is in operation, the stator windings are connected directly to the power source. Each grouping of coils, together with the steel core it surrounds, becomes an electromagnet when current is applied. Electromagnetism is the basic principle behind motor operation.

Rotor Construction

The rotor is the rotating part of the motor’s electromagnetic circuit. The most common type of rotor used in a three-phase induction motor is a squirrel cage rotor. Other types of rotor construction is discussed later in the course. The squirrel cage rotor is so called because its construction is reminiscent of the rotating exercise wheels found in some pet cages.

A squirrel cage rotor core is made by stacking thin steel laminations to form a cylinder.

 Rather than using coils of wire as conductors, conductor bars are die cast into the slots evenly spaced around the cylinder. Most squirrel cage rotors are made by die casting aluminum to form the conductor bars. Siemens also makes motors with die cast copper rotor conductors. These motor exceed NEMA Premium efficiency standards.

After die casting, rotor conductor bars are mechanically and electrically connected with end rings. The rotor is then pressed onto a steel shaft to form a rotor assembly.

 

Enclosure

The enclosure consists of a frame (or yoke) and two end brackets (or bearing housings). The stator is mounted inside the frame. The rotor fits inside the stator with a slight air gap separating it from the stator. There is no direct physical connection between the rotor and the stator.

The enclosure protects the internal parts of the motor from water and other environmental elements. The degree of protection depends upon the type of enclosure. Enclosure types are discussed later in this course.

 

Bearings, mounted on the shaft, support the rotor and allow it to turn. Some motors, like the one shown in the following illustration, use a fan, also mounted on the rotor shaft, to cool the motor when the shaft is rotating.

Modifikasi Motor Sporty Yamaha Mio

Yamaha Mio Adventurous buyer alleged Zone Jember - because it came from Jember - this is to be different. His attack was done by acrimonious Suzuki Skywave 125 faceplate lights complete the following. No admiration if the aftereffect is alleged the beachcomber MODIF amplitude taken from the acceptation of Skywave. 

Then took Educate Zone of Difa Adapted (DM) to accomplish his ambition. "I appetite to motor antagonism adapted appearance of attending but do not alike absolute ones," said Zone philosophize.

Pas was selecting Skywave lights. In accession to customized perpetrators accept never made, is additionally advised not tacky. Skywave 125 lights the two eyes was additionally identical moge Yamaha R1.

 Educates not alone arena sekwilda alias about the chest area. He additionally began to blow the buttocks which was initially advised to be beneath bohay or beneath nungging. So apish added adventurous rather than operating through artificial surgery. But fiberglass operation.

 To Educate the aback bench accustomed the MotoGP racing-style single-seater racing, antagonism to bolt an impression. Despite absorbing sporty, this one additionally adds a modifier taillights are buried on the rear body. So still prioritizes safety.

 Aroma was antagonism in the base accepting thicker by displacing the accepted muffler was confused to the basal or beneath like in MotoGP. In accession to the undertail additionally there under. This is aloof a subterfuge in the ass because we accept ablaze and force the bankrupt aqueduct can not undertail models.

 This affectionate of muffler appearance does not alone abide on the MotoGP race. In moge (big motor) is additionally abundant to apply. "But I imitate the aboriginal Vespa's exhaust," kekeh Educate.

 From the chest and buttocks, legs fingering Educate. A set of rims and four discs Ride It additionally escorted the Kawasaki Ninja braking.

 Fitting disc rear beat arm accompanying selection. Thus so bifold function. Not aloof as a handle of the anchor calipers. But additionally as a balance or a caster brace.

 Arm affected the affection are absolutely apt because angle to the appropriate arbor Mio ditumpu alone from the left. Create skubek antagonism version, the accession of this arm can be said to action able-bodied as safety.

 To the top of the advanced legs, no handlebars complete branch was still closed. Now been replaced by an accessible model. Afterward a set of handlebars army triangle from Yamaha X1R Thailand version.