A bank of three single-phase transformers, each rated 3 0 MVA , 38 . 1 / 3 . 81 kV , are connected in Y-Δ with a balanced load of three 1 Ω , Y-connected resistors. Choosing a base of 9 0 MVA , 66 kV for the high-voltage side of the three-phase transformer. spify the base for the low-voltage side. Compute the per-unit resistance of the load on the base for the low-voltage side. Also, determine the load resistance in ohms referred to the high-voltage side and the per-unit value on the chosen base.
A bank of three single-phase transformers, each rated 3 0 MVA , 38 . 1 / 3 . 81 kV , are connected in Y-Δ with a balanced load of three 1 Ω , Y-connected resistors. Choosing a base of 9 0 MVA , 66 kV for the high-voltage side of the three-phase transformer. spify the base for the low-voltage side. Compute the per-unit resistance of the load on the base for the low-voltage side. Also, determine the load resistance in ohms referred to the high-voltage side and the per-unit value on the chosen base.
A bank of three single-phase transformers, each rated
3
0
MVA
,
38
.
1
/
3
.
81 kV
,
are connected in
Y-Δ
with a balanced load of three
1
Ω
, Y-connected resistors. Choosing a base of
9
0
MVA
,
66 kV
for the high-voltage side of the three-phase transformer. spify the base for the low-voltage side. Compute the per-unit resistance of the load on the base for the low-voltage side. Also, determine the load resistance in ohms referred to the high-voltage side and the per-unit value on the chosen base.
1. A 220V d.c. shunt motor has a 5V brush drop, an armature resistance of 0.20, and a rated armature
current of 40A. Calculate:
(a) the counter-back e.m.f. (EC),
(b) power developed by the armature (Pd) in watts
(c) mechanical power developed by the armature in horsepower.
Ans.[207V, 8280 W, 11.099hp]
Tests are carried on 400 V, 60 Hz, Y-connected, wound rotor three-phase induction motor with
the following test results:
DC Test: 21 V, 43 A
No Load Test: 400 V, 20 A, 1200 W, 60 Hz
Blocked Rotor Test: 100 V, 44 A, 2700 W, 19 Hz
Find R1, X1, R2, X2, and Xm of this motor?
xxx₁ = 0.5xbm fy
Pen Pd
51-5
NN (1-5)
1208
1 [10Marks]
N
wr
P
5- A 250 V shunt motor operates on full load at 1500 rpm and draws line current 20 A.
The armature has 6 poles and is lap wound with 200 turns. Find the induced emf and the
flux/pole at full load. Given that the armature and field resistances are 0.5 and 125 2
respectively. Ans.[ 24.1 m Wb]
Chapter 3 Solutions
MindTap Engineering for Glover/Overbye/Sarma's Power System Analysis and Design, 6th Edition, [Instant Access], 1 term (6 months)
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, computer-science and related others by exploring similar questions and additional content below.
How does a Transformer work - Working Principle electrical engineering; Author: The Engineering Mindset;https://www.youtube.com/watch?v=UchitHGF4n8;License: Standard Youtube License