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41-116.1A
6.1.4. Voltage Unit (V)
1. Contact Gap – The gap between the stationary
contact and moving contact with the relay in a de-
energized position should be approximately .020".
2. Sensitivity – The contacts should close when
voltage is reduced to approximately 90 volts.
6.1.5. Telephone Relay (T)
The telephone relay has a dropout time of 250
±
milliseconds
50 milliseconds. It has a burden of 3.1
volt-amperes at 125 volts dc nominal. It should
pickup whenever the voltage unit contacts close.
6.2. ROUTINE MAINTENANCE
All relays should be inspected and checked once a
year or at other time intervals as dictated by experi-
ence to assure proper operation. Generally a visual
inspection should call attention to any noticeable
changes. A minimum suggested check on the relay
system is to close the contacts manually to assure
that the breaker trips and the target drops. Then
release the contacts and observe that the reset is
smooth and positive.
If an additional time check is desired, pass test cur-
rent through the relay and check the time of opera-
tion. It is preferable to make this test at several times
pick-up current at an expected operating point for the
particular application. Phantom loads should not be
used in testing induction-type relays because of the
resulting distorted current wave form which produces
an error in timing.
All contacts should be periodically cleaned. A contact
burnisher S#182A836H01 is recommended for this
purpose. The use of abrasive material for cleaning
contacts is not recommended, because of the danger
of embedding small particles in the face of the soft
silver and thus impairing the contact.
7. CALIBRATION
Us the following procedure for calibrating the relay if
the relay has been taken apart for repairs or the
adjustments disturbed. This procedure should not be
used until it is apparent that the relay is not in proper
working order (see "Operational Check").
NOTE: A spring shield covers the reset spring of
the CO unit. To remove the spring shield,
requires that the damping magnet be
6
removed first. The screw connection
holding the lead to the moving contact
should be removed next. The second
screw holding the moving contact assem-
bly
should
removed . (Caution: this screw terminates
into a nut held captive beneath the
molded block. If screw is removed, diffi-
culty will be experienced in the re-assem-
bly of the moving contact assembly.)
Slide the spring shield outward and
remove from relay. Tighten the screw
holding the moving contact assembly to
the molding block.
7.1. Overcurrent Unit (CO)
A. Contact
1) By turning the time dial, move the moving
contacts until they deflect the stationary con-
tact to a position where the stationary contact
is resting against its backstop. The index
mark located on the movement frame should
coincide with the "0" mark on the time dial. for
double trip relays, the follow on the stationary
contacts should be approximately 1/64".
2) For relays identified with a " T ", located at
lower left of stationary contact block, the
index mark on the movement frame will coin-
cide with the "0" mark on the time dial when
the stationary contact has moved through
approximately one-half of its normal deflec-
tion. Therefore, with the stationary contact
resting against the backstop, the index mark
is offset to the right of the "0" mark by
approximately .020". The placement of the
various time dial positions in line with the
index mark will give operating times as shown
on the respective time-current curves. For
double trip relays, the follow on the stationary
contacts should be approximately 1/32".
3) Set the time dial in position 6.
B. Minimum Trip Current
The adjustment of the spring tension in setting
the minimum trip current value of the relay is
most conveniently made with the damping mag-
net removed.
then
be
loosened,
not
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