TYPE 24—Edwards Synchronous Wired Clocks, Type E1
During normal operation, 120Vac is applied between the run motor and common lines to
operate the clocks until the 58th minute. At HH:58:00 of each hour, the 120Vac is re
-
placed by 120Vdc between the correction and common lines for a period of 200ms, with
the common line being positive. This pulse initiates hourly corrections for clocks that are
less than 60 minutes slow. At 5:58:09 AM and PM, an additional 120Vdc, 200ms pulse is
transmitted to correct clocks that are 60 or more minutes slow.
B-30
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
10 ASB MAX.
120Vac
2
2
= Diode bridge, 200V min PIV,
avg current = # clocks x 0.115A
1
= V250LA4 MOV or equal
1
AC RTN
BLK
RUN MOTOR
+
–
WHT
COMMON
1
RED
CORRECTION
Figure B-27
Edwards Synchronous Wired Clocks, Type E1