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7
(/)
w 5
a:
w
a_
�
_J
6
u
C)
z 3
a:
w
a..
0 2
SMALLER
Fig.
5. Typical
operating curves for the 70% sensitivity
type CA ge nerator relay
setting should be on the number 1 position.
Each type relay is designed for a specific sensi
tivity and hence once the correct relay is chosen for
a given application, no adjustment is necessary. If
necessary, the spring tension controlling minimum
operating current may be altered slightly.
In general, for generator protection, a study of the
of the current transformer characteristic curves unde r
short circuit conditions should indicate whether the
the
high sensitivity
( 25%) relay should be used. Use the 25% relay, if
a-c
saturation causes more than 1% ratio error in
either set of CT' s.
*
Indicating Contactor Switch (ICS)
The only setting required on the ICS unit is the
selection of the 0. 2 ampere tap setting or 2.0 a mpere
tap setting. This selection is made by connecting the
lead located in front of the tap block to the desired
setting by means of the connecting screw. When the
relay energizes a 125 or 250 volt d-e type WL relay
switch, or equivalent, use the 0. 2 ampere tap.
4
RESTRAINT
AMPER£S
260208
Curve
(
10%) or
the low sensitivity
14
13
12
_J
II
0
u
10
C)
z
j::
<( 8
a:
w
a..
7
0
� 6
(/)
w
5
a:
w
a_
� 4
<(
3
0
0
10
20
SMALLER RESTRAI NING
Fig.
6. Typical
operating curves for the 25% sensitivity
type CA generator re lay.
INSTALLATION
The
relays should be mounted
panels or their equivalent in a location free from dirt,
moisture,
excessive vibration, and heat. Mount the
relay vertically by means of the four mounting holes
on the flange for semi-flush mounting or by means of
the rear mounting stud or studs for projection mount
ing. Either a mounting stud or the mounting screws
may be utilized for grounding the relay. The electrical
connections may be made directly to the terminals by
means of screws for steel panel mounting or to the
studs furnished with the relay for thick panel mount
ing.
The terminal studs may be easily removed or
inserted by locking two nuts on the stud and then
turning the proper nut with a wrench.
For detailed FT case information refer to I .L. 4 1-076.
ADJUSTMENTS AND MAINTENANCE
The proper adjustments to insure correct o peration
of this relay have been made at the factory and
should not be disturbed after receipt by the customer.
A cce p tance
Te st s
The following
check is recommended to insure
30
40
50
A MPERES
252217
Curve
on switchboard
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