Operating Procedures
EZCT™
and
EZCT-
10
21
6.1.2 Run Ratio Only Test
The EZCT performs the CT turns ratio test using the voltage method. The EZCT can also
compare the CT measured ratio against the name plate ratio and generate the percentage error.
The percentage error is calculated as follows:
%
Er
r
or
=
[
(
Me
a
s
ur
e
d
r
a
t
i
o
–
Na
me
pl
a
t
e
r
a
t
i
o)
/
Na
me
pl
a
t
e
r
a
t
i
o]
x
100
%
The CT measured turns ratio and winding polarity is displayed on the LCD during test (see 6-4).
A typical turns ratio report is shows in Figure 9.
Table 6 Run Ratio Only Test
STEP
ACTION
DISPLAY
6-1
None. EZCT Main menu.
6-2
Begin RUN TEST procedure: Press key # 1
(RUN TEST) on the MAIN MENU.
6-3
Select Ratio Only Test by pressing key # 2.
6-4
To have the EZCT calculate the percentage
error, enter the transformer nameplate ratio
by pressing key #1 (YES).
6-5
Enter the transformer nameplate ratio.
NOTE
Ent
e
r
t
he
“
hi
gh
s
i
de
”
numbe
r
t
he
n
pr
e
s
s
t
he
“
ENTER”
ke
y
t
o
e
nt
e
r
t
he
“
l
ow
s
i
de
”
numbe
r
.
Pr
e
s
s
t
he
“
ENTER”
ke
y
a
ga
i
n
t
o
confirm.
1.RUN TEST
07/06/06
2.SETUP
16:22:01
3.DIAGNOSTIC
1.EXCITATION & RATIO
2.RATIO ONLY
XFMR NAME PLATE RAT.
1.YES
2.NO
ENTER PLATE RATIO
0 :
ENTER PLATE RATIO
2200 : 5.0
