@ @
@)
@)
TD-52
REL AY
STOP
NOTE: CONNECTIONS SHOWN
ARE FOR
T2 UNIT
FOR
T3
UNIT USE
TERMIN ALS
13, 14, 18,8 19
INSTEAD
OF
3,4,8, a 9
RESPECTIVELY.
D-C
SUPPLY
POS
VOLTAGE
D.PS.T
SWITCH
TIMER
35 16A46
Fig. 5. Test Circuits for Type TD-52 Relay.
sistance de voltmeter. It is necessary to scrape
varnish from the capacitor positive terminal in
order to make a connection at this point. The
brush voltage, which is constant until the tele
phone relay trips, should be approximately one
half the reference voltage. The capacitor should
gradually change to the potentiometer brush
voltage, plus approximately one volt for silicon
junction forward voltage drops through SCR
and D2.
4.
If reference voltage, capacitor voltage, and
potentiometer voltage all appear to behave
correctly, the SCR may be the cause of trou
ble. The anode to cathode voltage, as
measured between printed circuit terminals
4
and 3, should be approximately one-half the
reference voltage until the capacitor voltage
reaches the brush voltage, at which time the
anode to cathode voltage should drop to ap
proximately one volt.
CALIBRATION
Use the following procedure for calibrating the
relay if the relay adjustments have been disturbed.
This procedure should not be used until it is ap-
parent that the relay is not in proper working
order. Before calibrating, follow the Trouble
Shooting Procedure to locate the source of trou
ble.
1. TELEPHONE TYPE RELAY ADJUSTMENT
Adjust the armature gap on the telephone type
relay to be approximately
.004
inch with the ar
mature closed. This is done with the armature set
screw and lock-nut. Also, adjust contact leaf
springs to obtain at least
.015
inch gap on all con
tacts and at least
.010
inch follow on all normally
open contacts and at least
.005
inch follow on all
normally closed contacts.
2.
RHEOSTAT KNOB ADJUSTMENT, SAME
SCALE PLATE
If it is necessary to replace the rheostat (T2) or
(T3) or the silicon power regulator
(Z),
the relay
may be recalibrated with the same scale plate, in
most cases. This is done by rotating the rheostat
shaft, without knob, until a time delay equal to the
minimum scale marking is obtained. Then, align
the knob for this delay and tighten the knob set
screw securely. Pause several seconds between
readings for all delays above
0.5
seconds. See sec
tion under Accuracy for discussion of this.
3. SCALE PLATE CALIBRATION, NEW
SCALE PLATE
If it is necessary to replace the potentiometer
(P) or the printed circuit, the relay should be
recalibrated with a new scale plate. Use the
following procedure:
(a) With the knob off the shaft, set the rheostat
(T2) or (T3) at maximum.
(b) Adjust P so that the times are
5%
to
10%
longer than the maximum scale marking.
(c) Set the rheostat (T2) or (T3) at minimum
and check that times are less than or equal to the
minimum scale marking. If not, adjust P slightly
to reduce times. Tighten lock nut on P.
(d) Place the knob on the rheostat shaft in such
a position that the times are symmetrical with
respect to the scale plate marking. Tighten the
knob set-screw and mark calibration lines on the
scale plate. When striking calibration lines for
7
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