Transformer Problem A 480V 120 V 60 Hz transformer has its

Transformer Problem: A 480V ~ 120 V, 60 Hz transformer has its high voltage winding connected to a 440V supply. and low side to a 2 ohm 30 degree load. Assuming the transformer is ideal, determine: Secondary voltage; Secondary current; Primary current; Input impedance at the primary terminals: P, Q. and S; S in polar form (get the correct + or - on); Draw the power triangle and label the sides. e). f), and fc) are tor the load side. Now suppose the transformer is not ideal, and an open circuit test reveals the following V_pri vs. I_pri curve:

Solution

480/120 V transformer

Turns ratio N2/N1= V2/V1=I1/I2=120/480 =0.25

(a) Primary Volatege V1=440 V

Secondary Voltage V2=V1*N2/N1=440*0.25=110 v

So V2=110 V

(b)Secondary current I2= V2/Z where is Z is secondary side impedance

I2=110/2<30=55 <-30^o A

I2=55 <-30^o A

(c) Primary current I1=I2*N2/N1=55<-30^o *0.25=13.75<-30^o

I1=13.75<-30^o

(d) Input Impedance Zi=Z*(N1/N2)^2=2<30^o*(16)=32<30^o

Zi=32<30^o