TYPE 18—National Synchronous Wired
For a list of Type 18 clocks, see the chart on the first page of this appendix.
Relay K5 is normally operated to power the clock run motors. Each hour from HH:00:00
to HH:00:28, relay K6 is operated to power the clock correction coils for 28 seconds and
cause hourly corrections. Every 12 hours, from 6:00:00 to 6:27:27, relay K6 is again op
-
erated to power the clock correction coils for 27 minutes, causing 12-hour correction.
Manual clock corrections can be issued from the master during any even-numbered
minute except 00.
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24A715/24A715M Master Clock Installation Manual
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CLK1 OR CLK2
x
x
x
x
RELAY
K6 (K8)
RELAY
K5 (K7)
II
MASTER CLOCK
FIELD CONNECTIONS
X = Normally open contact
I = Normally closed contact
SOURCE
POWER
10 ASB MAX.
CORRECTION COIL
RUN MOTOR
RETURN
1
= V250LA4 MOV or equal
1
1
1
Figure B-21
National Synchronous Wired