01-11-2012, 05:41 PM
Transformers
Transformers.pptx (Size: 339.61 KB / Downloads: 47)
Transformer Specifications.pptx (Size: 68.69 KB / Downloads: 132)
Transformers1.pptx (Size: 51.37 KB / Downloads: 38)
Transformer3.pptx (Size: 69.88 KB / Downloads: 44)
Testing of Transformers.pptx (Size: 68.22 KB / Downloads: 42)
Standards and specifications
Standards and specifications are documents that stipulate or recommend
1) minimum levels of performance and quality of goods and services and
2) optimal conditions and procedures for operations in science, industry, and commerce, including production, evaluation, distribution, and utilization of materials, products, and services.
Types of standards
Category, type, dimension, structure, equipment, quality, grade, component, performance, durability, or safety
Methods of manufacturing, methods of designing, methods of drawing, methods of using, or methods of operation of safety condition of production
Methods of testing, analysing, appraising, verifying, or measuring
Terms, abbreviations, symbols, marks, preferred numbers, or units
Design, methods of execution, or safety conditions
Points to remember
Some standards are government-mandated, and others are voluntary. There may be various penalties associated with not adhering to the standard
Standards are updated frequently to keep pace with changing technology
Specification of transformer
International standards published by IEC are accepted universally
Each nation has its own national standards which are based on particular requirements and practices of that nation
Indian Standards Institution (Indian Bureau of Standards) publishes IS standards
Manufacturers and users in India recognise IS standards and IEC standards
Standard specifications of a Power transformer (IS 2026)
Type of Transformer – separate winding transformer, auto-transformer or booster transformer
Number of phases, single or polyphase
Frequency
Rated power (in kVA) and for tapping ranges exceeding ±5% required power on extreme tappings
Rated voltages for each winding
Connection symbol
Requirement of on-load/off-circuit tap-changers or links – number of tappings, tapping range, location of tappings, particular voltage to be varied and whether constant flux/variable flux/ combined voltage variation
Impedance voltage at rated current and principal tapping for different pairs of windings and atleast on the extreme tappings in case of parallel operation if required
Indoor or outdoor type
Type of cooling and if different types of cooling is involved , rated power for each type of cooling