TYPE 22—Dukane Synchronous Wired (24A Series, Obsolete)

During normal operation, either 24Vac or 120Vac is furnished to the clock run motor through relay K6. Power is removed from the run motor during power failures, while K6 de-energizes during fall daylight saving changes.

Each hour from HH:57:00 to HH:57:55, relay K5 energizes to furnish a 24Vdc signal to the correction coil. This 55-second signal causes all secondary clocks to advance to the 58th minute, thus synchronizing the seconds and minutes with the master clock.

The 12-hour correction occurs twice daily, beginning at 5:59:00. Every other minute from 5:59:00 through 6:19:55, relay K5 energizes to furnish eleven 24Vdc signals of

55 seconds duration to the clock correction coils (5:59:00 to 5:59:55, 6:03:00 to 6:03:55, 6:19:00 to 6:19:55).

These eleven signals cause all secondary clocks up to 11 hours behind to advance to 5:58:00. Hours, minutes, and seconds are synchronized to the master clock after the next hourly correction at 6:58:00. Clocks more than 11 hours behind prior to a 12-hour correction require two 12-hour corrections to advance to 5:58:00.

X = Normally open contact

I = Normally closed contact

1 = V250LA4 MOV or equal

 

 

 

 

 

 

 

 

 

2 = 1N4004 diode or equal

 

 

 

RELAY

 

 

 

 

RELAY

 

 

K5 (K7)

 

 

 

 

K6 (K8)

 

 

 

 

 

 

 

 

 

x

 

x

I

 

I

 

 

 

 

 

 

 

 

x

 

 

 

CLK1 OR CLK2

 

 

 

 

 

 

 

 

MASTER CLOCK

1

2

3

4

5

6

7

8

 

FIELD CONNECTIONS

10 ASB MAX.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

24Vac/120Vac

 

 

 

 

 

 

1

 

TO CLOCK

 

 

 

 

 

 

 

 

RUN MOTOR

 

 

 

 

 

 

 

 

 

10 ASB MAX.

 

 

 

 

 

 

 

 

 

+

 

 

 

 

 

 

 

 

TO CLOCK

24Vdc

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

CORRECTION COIL

–

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure B-25

Dukane Synchronous Wired (24A Series, Obsolete)

B-28

24A715/24A715M Master Clock Installation Manual