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WORK # 4 ECE 320

Figures (a) and (b) show two possible connections for a 20
kVA, 2300/230V transformer to be used as an autotransformer.  With
a source voltage of 2300 V, calculate the kVA rating and the power output at full load of unity power f</span><span
class="Normal--Char" style=" font-size: 11pt;">actor (p.f=1) of the
autotransformer for both the connections.

style=" margin-top: 24pt;">   

      2. A 6.6 kVA 10kV/230 V, 60Hz, single-phase transformer has following
parameters

style=" text-indent: 36pt;">referred to the high voltage side:

style=" margin-top: 12pt; text-indent: 108pt;">R</span><span class="Normal--Char" style=" font-size: 7pt;
">wdg =
20 , L</span><span class="Normal--Char" style=" font-size: 7pt;">l = 9 H, R</span><span
class="Normal--Char" style=" font-size: 7pt;">c = 250 k, L</span><span class="Normal--Char" style=" font-size: 7pt;">m = 10 kH.

style=" margin-top: 12pt; text-indent: 36pt;">a) What are the open
circuit (rated voltage on the low voltage
side) and
short circuit (rated

style=" text-indent: 36pt;">current  on the high voltage side) voltage, current and power test results.

style=" margin-top: 12pt; text-indent: 36pt;">b) If the secondary
voltage is 230 V, and the power is 5 kW at .866 lagging, calculate the

style=" text-indent: 36pt;">efficiency in p.u. values.

style=" margin-top: 36pt; margin-left: 36pt; text-indent: -36pt;
">   
3. A three-phase transformer is made from three single-phase ones, each
single-phase transformer is rated 10 kVA, 20 kV/200V; rated winding
losses 100 W, core losses 50 W. The three-phase transformer is connected
in delta on the high voltage side and in star on the low voltage side.
What are the voltage ratings, current ratings, core loss (at the rated
voltage), winding loss (at the

style=" text-align: justify; text-indent: 36pt;"> rated current) for
the 3-phase transformer?