Discussion in 'Homework Help' started by placide, Oct 1, 2011.

1. ### placide Thread Starter New Member

Oct 1, 2011
22
0

1) A transformer:100kvA, 50Hz, 600v/230v has been tested as follow:
at no load: V1=6000v, V20=240v, Iο=0.5A, Pο=400w at short circuit :
V1sc=200v, I1sc=16A, P1sc=1500w

a. determine the secondary voltage for the normal secondary current and with
1. cosØ=1
b. the same machine, determine the efficiency for animal current and power factor
0.7 lagging.
c. determine the value of r and x for this calculate the value of relative
voltage drop for a current equal to the half of the nominal current and
a power factor of 0.6 lagging.

2) A 20kvA 8000/480v distribution transformer has the following resistances and
Reactances: Rp=32Ω Rs=0.5Ω
Xp=45Ω Xs=0.6Ω
Rc=250kΩ Xm=30kΩ

The excitation branch impedances are given referred to the high-voltage
Side of the transformer
a. find the equivalent circuit of this transformer referred to the voltage side
b. find the per-unit equivalent circuit of transformer
c. assume that this transformer is supplying rated load at 80v and 0.8pf lagging what is this transformers input voltage
d. what is the transformers efficiency under the condition of part(c)

2. ### Georacer Moderator

Nov 25, 2009
5,151
1,266
The rules of the Homework Help forum require you to post your efforts before receiving any help.

So please post any work you have done so far or efforts in solving your problem, and we 'll be happy to correct you or point you to the right direction.

3. ### stinky111 Member

Apr 7, 2011
39
1

This is Classic,, Join the forum the day before your assignment is due, then post, asking for someone to do it for you!!!
R u serious ??

4. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
783
I'm surprised you are surprised / incredulous. Nothing unusual there ....