transformers types.pptx
- 1. Introduction Construction Principal Working Advantages Disadvantages
- 2. Generation of electrical power of usually three phase and at higher voltage Like 13.2Kv,22Kv Or some what higher Similarly transmission of electrical power is also Very high voltage like 110Kv, 132Kv,400Kv To setup the Generated voltage for transmission Purpose it is necessary to have three phase Transformers
- 4. The three cores are arranged at 120 degree from each other. Only primary windings are shown On the cores for the simplicity The primary connected to to the three phase supply The three fluxes are zero at any instant
- 5. Hence the centre leg does not carry any flux So if centre leg is removed, any two legs Provide the return path of the current and ,hence The flux in the third leg This is the general principle used in the design of 3 phase core type transformer
- 6. The primary and secondary winding of 3 phase transformers as three phase windings can be connected in different ways Such as in star or in delta with suitable connection the voltage Can be raised or lowered In this section Some commonly user connections For 3 phase transformer are discussed
- 7. Star-star connection Delta-Delta connection Star-Delta connection Delta-Star connection
- 14. It Occupies less space Its weight is Less Its cost is comparatively less It is much easy to transport It is more efficient Its core size is comparatively small
- 15. When One of the phases of a Single unit 3 phase transformer becomes faulty,The entire Unit of three phase transformer Needs to removed from the Supply for repair But in the case of bank Of the three phase transformer, only the faulty transformer is removed From the supply for the repair While the other two transformers Remains connected in the system Without interrupting The supply completely
- 16. Introduction Types of auto transformers Advantages of auto transformers Disadvantages of auto transformers Applications of auto transformers Limitations of auto transformers
- 17. Introduction • An auto transformer is an electrical transformer with only one winding • In an auto transformer,Portions of the same winding,Act as both Primary and secondary Sides of the transformers
- 18. Step up autotransformers Step down auto transformers
- 19. • An Auto transformer in which Ns>Np is called step up auto transformer • An Step up auto transformer Is a transformer in which convert low alternating current into high alternating current
- 20. • An auto transformer in which Np>Ns is called step down auto transformer • An step down autotransformer is an transformer which converts low low alternating voltage into high alternating voltage
- 21. An auto transformer requires Less copper Then two windings transformers Similar ratings An auto transformers operates at a higher efficiency Then two windings transformers of similar ratings An auto transformer has better rating of voltage regulation then two winding transformer of similar rating An auto transformer have a smaller size then two winding transformer of similar rating An auto transformer requires less exciting current,than Two winding transformer of similar rating
- 22. There is a direct connection between primary and secondary windings, therefore The output is no longer D.C Is isolated from the input An auto transformer is not safe for Stepping down high voltage into low voltage The short circuit current Is much larger than for two windings Transformers of same rating,So that the short circuited secondary Part of the primary also To be short circuited. This reduces the effective resistance and reactance
- 23. Auto transformers are used to compensate For voltage in transmission and distribution line. When used for this purpose they are also called as booster transformers Auto transformer are used to to reducing the the voltage supplied to AC motors during starting time Auto transformers are used for continuously varing supply In control equipment for or one phase and three phase locomotive electricals
- 24. IT requires both fever windings and smaller core , an auto transformer for power application is typically lighter And less costly then two winding transformer upto the voltage ratio as 3:1 Like multiple winding transformers,Auto transformers operates on time varying Magnetic fields and so will not function in DC A failure of the installation of the windings of the transformer Can result in full input voltalge Applied to output .also a break In the part of the winding That is used as both primary and secondary Will result in the transformer acting As an inductor with load