Wednesday, March 23, 2011

Mastech 5K VA VARIABLE TRANSFORMER VARIAC 5000VA 0-250V

!: Best Buy Mastech 5K VA VARIABLE TRANSFORMER VARIAC 5000VA 0-250V grand sale

Brand : Acifica | Rate : | Price : $169.95
Post Date : Mar 23, 2011 13:20:14 | Usually ships in 1-2 business days


  • Output: 0-250V AC, Input: 110V AC/ 60 Hz
  • Maximum power output: 5000 VA
  • Maximum current output: 20 Amps@250V
  • Dimension: 11.8" X 13.4" X 14.6"
  • Warranty: 1 year

More Specification..!!

Mastech 5K VA VARIABLE TRANSFORMER VARIAC 5000VA 0-250V

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Friday, March 18, 2011

choosing Right Transformer For Mining business

!: choosing Right Transformer For Mining business

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Introduction

The Us has one of the largest mining industries in the world - an industry intimately related with the economy. In the past, the discovery of resources such as gold and oil resulted in a major people shift and rapid growth for once remote regions of the country, such as California, Texas, and Alaska. Discharge of these resources, and finding new deposits, continues to contribute the foundation for local economies in some regions.

Some of the minerals mined in the Us are coal, uranium, copper, gold, silver, iron, lead, zinc and others. Most of the mines in the Us are extremely automatic and thus vigor intensive. To contribute an example, even in the last decade of the 20th century, iron ore mining alone consumed 62.3 trillion Btu of vigor over a calendar year. Because mining is such a large industry and makes a astronomical offering to the national income, mines must have a reliable source of power - a crucial resource for mining processes.

The mining and mineral Discharge sector both in the Us and worldwide relies heavily on vigor to harness natural resources such as aggregates, high-priced metals, iron ore, oil, gas, and coal. This vigor is used to power shovels and drills for excavating these products, loading them into astronomical mining trucks or onto conveyer belts, sorting, sifting and crushing ores, heating, and a hundred other functions. Both exterior and underground mining operations rely on powered equipment to passage materials and load trucks. Overall, the mining sector could not flourish without the use of vast amounts of energy.

The Role of Transformers

Mine 'Power Centers' or 'Load Centers' are an important principles for underground and exterior mining. Their customary function is to convert distribution voltage into utilization voltage for equipment operation, thus placing power transformers at the heart of the load center. Permissible choice of transformers is imperative, and must fulfill safety, reliability, and efficiency requirements. Determining capacity rating is among the first steps for choice of a power transformer for a mining load center. A rule of thumb here is to allow 1 kVa for every horsepower of related load. Most mining processes, however, do not yield constant loads - all machinery is not related all the time - and therefore the 1 kVa per horsepower thumb rule will typically ensue in transformer oversizing. Agreeing to the Sme Mining Engineering Handbook by Howard L. Hartmann, "Past sense and query factors established by manufacturers and operators, along with the horsepower of the related load, are important for determining transformer capacity. For typical underground mining sections, the kVa rating may lie within the range of 50 to 80% of the related horsepower."

Transformer Losses

Standard transformers while under full load control at 90 to 95% efficiency, with this shape dropping as the load lightens. This is due to inefficiencies in the transformer's core, a main component of the transformer. The losses in the core remain the same throughout the transformer's operating range. At 100% load, the number of comparative loss is negligible. However, at reduced loads, the same number of vigor loss represents a higher ration of vigor being wasted. Unfortunately, median transformer loads run between 34 and 50% of the transformer's total capacity. With the majority of the electricity used

in the Us being run straight through transformers at these lower loads, immense amounts of vigor are being wasted. This issue is of extra relevance to the mining industry, naturally because of its high vigor usage. Mining operations also involve hostile environments full of dust, dirt, chemicals, moisture and airborne contaminants. Load town transformers need to function reliably and efficiently in these environments over a long term.

Without electric power at mining facilities, the natural materials extracted from the earth in the mining process would be much more high-priced than they are today. Thus, power transformers contribute a lot of muscle, capacity, and stability to an important industry. From drilling trenches to busting up rock, carting out huge loads of materials and pulling up heavy amounts of minerals, power transformers contribute the force and quality needed.

Liquid Filled and Dry Transformers: operation Characteristics

1.Liquid-Filled Transformers

While there is still debate on the relative advantages of the available types of transformers, there are some operation characteristics that have been accepted: • Liquid-filled transformers are more efficient, have greater overload quality and longer life expectancy. • Liquid-filled units are good at reducing hot-spot coil temperatures, but have higher risk of flammability than dry types. • Liquid-filled transformers sometimes need containment troughs to guard against fluid leaks. • Liquid filled transformers are smaller in size than dry-type units for the same power rating capacity and have lower losses because of their good thermal dissipation characteristics.

2.Dry Type Transformers

Dry type Transformers are commonly used for lower ratings (the changeover point being 500kVa to 2.5Mva). They are commonly settled indoors, serving an office building/apartment. Dry type units typically come in enclosures with louvers, or sealed.

Dry type transformers use almost no flammable materials and therefore do not constitute a fire hazard when used underground in both coal and other mines.

Dry type transformers in the mining industry are housed in a steel tank and the core and windings are cooled by air circulating within the tank, transferring heat to the steel tank which is in turn cooled by the external air. In some contract designs for mounting on mining machines water cooling is added to additional heighten the operation of the transformers.

Correct choice of insulating materials and an understanding of the cooling principles is imperative if the transformer is to be correctly designed. For example, a temperature rise test conducted on a transformer artificial and sold as continuously rated, can review that the transformer only had a continuous rating of 65% of the nameplate rating.

The Need for Energy-Efficient Mining

With the current focus on climate convert and reduction of environmental impact, government agencies around the world are making increasingly stringent demands on industries to cut vigor consumption and manage waste more effectively, among others. It is surprising how many mining operations still use twenty-year-old technology.

Regulatory pressures are already starting to affect the mining industry - Agreeing to an narrative on 'Us Environmental Regulations and the Mining Industry' on the International improvement study town (Idrc) website, "Environmental regulations have had an ensue on the Us mining industry's profitability. Fellowships have been forced to retrofit or renovate installations or leave the market. Expanding operational costs have affected their international competitiveness, and to some extent, this may be changing the world allocation of mining investment. Employment levels have fallen substantially, and local economies have borne part of this cost."

Mining Fellowships in the Us are thus feeling the pressing need to be energy-efficient, naturally to stay competitive. Reducing vigor consumption by adopting customized, cost-effective solutions like Nema-approved transformers and harnessing solar or wind vigor to meet their time to come vigor needs can be good ideas in the long run, especially since the alternate vigor choice will help mining Fellowships keep away from fluctuating international fuel prices. Alternate sources of vigor are still a very small blip on the graph, in terms of actual power in Case,granted for industries like mining, and thus the sector as a whole needs to come up with more immediate ways to conserve energy.

Various types of transformers for the mining industry:

Transformers can be used in various open pit and hard rock (subterranean) applications that range from auxiliary lighting loads to power for cranes, drag lines, conveyor belts and other miscellaneous dedicated changeable speed drive applications.

Benefits of energy-efficient mining
• Reduced cost of yield
• opening up of new reserves for Conclusion

On one hand the mining industry is all set to grow to keep up with Expanding demand; on the other it has to stay contentious as fuel prices zoom upwards. For an vigor arduous industry, holding a check on fuel consumption and cost is critical. Thus the mining industry as a whole is finding for vigor productive technology, along with power transformers.


choosing Right Transformer For Mining business

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