TUGAS TRAFO
TRANSFORMATOR
1. A-150 kVA transformer has 400 turns on the primary and 80 turns on the
secondary. The primary and secondary resistances are 0.25 Ω and 0.013 Ω respectively
and
the
corresponding leakage reactances are 1.1 and 0.036 Ω respectively. The supply voltage
is
2200
V.
Calculate (a) equivalent impedance referred to primary and (b) the voltage regulation and
secondary terminal
voltage
for full
power
of 0.8 leading.
2. the
A short-circuit
test when
performed
onload
the having
h.v. sidea of
a 10factor
kVA, 2000/400
V single phase
transformer, gave the following data ; 60 V, 4 A, 100 W. If the 1.v. side is delivering full
load current at 0.8 p.f. lag and at 400 V, find the voltage applied to h.v. side.
3.
Trafo tenaga 60 kVA : 2300/230 V, 50 Hz digunakan sebagai trafo distribusi. Pada arus sekunder
beban penuh dengan factor daya tertinggal 0,8.
Tentukan :
a. Besar impedansi beban trafo tersebut
b. Arus primer, jika arus trafo tanpa beban sebesar 5 A dengan factor daya tertinggal 0,37
4.
5.
A 20-kVA, 2200/220-V, 50-Hz distribution transformer is tested for efficiency and regulation
as follows :
O.C test : 220 V ; 4.2 A ; 150 W - l.v. side
S.C. test : 85 V ; 10 A ; 360 W
- l.v. side
Determine (a) core loss (b) equivalent resistance referred to primary (c) equivalent
resistance
referred to secondary (d) equivalent reactance referred to primary (e) equivalent reactance
referred
to secondary (f) regulation of transformer at 0.8 p.f. lagging current (g) efficiency at fullload
andof 1000 kVA at 0.86 p.f. lagging is supplied by two 3 phase transformers of
A load
half
full-load
at 0.8
p.f. lagging
current Ratio of transformation is same : 6400/400
800the
kVA
capacity
operating
in parallel.
V, delta/ star. If the equivalent impedances referred to secondary are (0.005 +
j.015) ohm and (0.012 + j 0.030) ohm per phase respectively. Calculate load and
power factor of each transformer.