CHAPTER XI. 



Transformer on Open Secondary Circuit Hysteresis Loss Eddy-current Loss 

 Lamination of Core Transformer working under Load Calculation of 

 Eddy-current Loss Effect of Shape of P.D. Curve on Iron Losses Tests 

 of Transformers. 



MONO-PHASE TRANSFORMERS. 



59. A mono-phase stationary transformer consists, in its simplest 

 form, of two coils of wire wound on the same iron core, as in 

 Fig. 36. 



Between the terminals of one of the circuits the primary 

 circuit an alternating P.D. is applied. 

 This causes a current to flow through 

 the primary coil, producing an alterna- 

 ting magnetic field which cuts the wind- 

 ings of the other circuit the secondary 

 circuit. An alternating E.M.F. is thus 

 induced in the secondary circuit, giving 

 rise to a secondary current if the 

 secondary terminals are connected to an 

 external circuit. 



Transformer on Open 

 Secondary Circuit. It will 



readily be seen that the presence of a secondary circuit renders a 

 study of the transformer somewhat complicated, since the mutual 

 reactions of the two currents have to be taken into consideration. 



To make matters as simple as possible, it is advisable to com- 

 mence by supposing that the secondary circuit is open, so as to 

 have only the primary current and its effects to consider. 



Let EI be the E.M.S. potential difference applied between the 

 primary terminals, n the resistance of the primary coil, si its 

 reactance, and ii the E.M.S. value of the primary current on open 

 secondary circuit. 



