Electrical Machine, Types of transformer, Phase diagram of transformer and equivalent circuit of transformer

 TYPES OF TRANSFORMER - :

There are many types of transformer -

Measurement 

1.CORE TYPE  TRANSFORMER - : In core type transformer, two winding are arranged as concentric coils, therefore these are called concentric winding or cylindrical winding. The low voltage winding is placed next to the  core and the high voltage winding is placed around the low voltage winding to reduce the insulation material requirement. 

SHELL TYPE TRANSFORMER - : In the shell type of transformer bith primary and secondry winding are wound on tje central limb and the two outer limbs complete the low reluctance flux paths. 

                                            Each winding is subdivided into sections. Low volrage and High voltage subsections are alternatly lut in the form of a sandwich. Therefore, such a winding is placed called sanfwich or disc winding. 

IDEAL TRANSFORMER - :An ideal transformer is one which has following assumptions:

1. Its winding haveno Ohmic resistance, therefore it jas no I2R loss (copper loss). 

2.    There is no magnetic leakage, hence which has no core losses(hystresis as well as eddy current loss). 

3.     The core has infinite permebilitycso that zero magnetizing current is needed to establish the requisite amount of flux in the core. 

MMF BALANCE IN IDEAL TRANSFORMER - 

       N1I1-N2I2=0

         N1/N2=I2/I1

        E1/E2=   N1/N2=I1/I2=K=V1/V2   

        E1I1=E2I2=S2=S1 

or, 

      It showes that the voltampere drawm from the primary supply is equal to the voltampere transfrlerred to the secondary supply without any loss in an ideal transformer. 

V1I1/1000=V2.I2/1000

(KVA)1= (KVA) 2

  INPUT KVA=OUTPUT KVA

Thus the kva input of an ideal transformer is equal the kva output  kva is the same an both sides of transformer. 

PHASE DIAGRAM OF TRANSFORMER - :

1.WHEN TRANSFORMER AT NO LOAD-:

               A transformer is said to be at no load when the second winding is open circuited. Thus, secondary current will be zero. When  an alternative  voltage is applied to the primary, a small current will be zero. When a alternative voltage is applied to the primary, a small current I0 flows in the primary winding. The current I0 is called the no load current or exiting current of the transformer. The no load curren I0 us small og the order of 3%to 5% of the rated current of primary wimding. It can be resolved into two components. 

(a)  The components is called the magnetizing current. it magnetizing the core. it sets up a flux in the core, therefore Im is in phase with. Itcis also called reactive or wattless component of no load current. 

(b). The component is called core current. It is also called active components of mo load active current. it is in phase with the primary induced voltage. the  componant supplies the hysteresis and eddy current loss in the core and the neglible loss in the primary winding.