I.L. 41-748.1F
16
8. INSTALLATION
The relays should be mounted on switchboard pan-
els 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 the ter-
minal studs furnished with the relay for thick panel
mounting. 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. 41-076.
9. ADJUSTMENTS AND MAINTENANCE
The proper adjustments to insure correct operation of
this relay have been made at the factory. Upon
receipt of the relay, no customer adjustments, other
than those covered under “SETTINGS’, should be
required.
9.1.
ACCEPTANCE CHECK
The following check is recommended to insure that
the relay is in proper working order:
A. Distance Unit (Z)
1.
Connect the relay as shown in figure 9 with
the switch in position 2 and the trip circuit
deenergized.
2. Make the following tap settings:
T
A
= 11.5
T
C
= 2.55
S
A
= 2
S
C
= 1
M
A
= -.03
M
C
= -.09
T
C
link in middle block should be set for +T
C
direction.
This setting corresponds to Z
A
= 23.7 Z
C
=
2.80.
Adjust the phase shifter for 90˚ current lag-
ging the voltage.
3. With the terminal voltage at 50 volts,
increase current until contacts just close.
This current should be within
±
3% of 2.11
amp (2.20 - 2.05 amp).
4. Adjust phase shifter for 90˚ current leading
the voltage.
5. With the terminal voltage at 50 volts increase
current until contacts just close. This current
should be within
±
3% of 17.9 amps, (18.5 -
17.3 amps).
Contact Gap – The gap between the stationary con-
tact and moving contact with the relay in deenergized
position should be approximately .040”.
B. Directional Unit Circuit (D)
1.
Connect the relay as shown in figure 9, with
the switch in position 1 and the trip circuit
deenergized.
2. With a terminal voltage of 1 volt and 5
amperes applied, turn the phase shifter to
43˚ (current leads voltage). The contacts
should be closed. This is the maximum
torque position.
3. Raise the voltage to 69 volts and vary the
phase shifter to obtain the two angles where
the moving contact just makes with the left
hand contact. These two angles (where
torque reverses) should be where the current
leads the voltage by 313˚ and 133˚,
(±
4˚).
4. Contact Gap – The gap between the station-
ary contact and moving contact with the relay
in deenergized position should be approxi-
mately .020”.
C. Undervoltage Circuit
1.
Connect the relay as shown in figure 9, with
switch in position 2 and the trip circuit deen-
ergized.
2. Decrease the voltage until the contacts close
to the left. This value should be 53
±
3%
volts.
D. Telephone Relay – Apply rated dc volts across
terminal 10 and 3. The telephone relay (X)
should open its contact. Manually close distance
unit (Z) and directional unit (D) contacts and the
X contact should close.
