Figure 5-20. Under and Overfrequency Devices, Test Setup
light control film (6) on the front of the panel using
Mount the digital clock (7) using screws (1).
Connect lead wires and remove tags.
5-11. ALARM HORN.
Removal. Remove alarm horn (18, figure 5-1)
MAINTENANCE PROCEDURE, SET
MAINTENANCE LOCKOUT SWITCH
BATTERIES. REMOVE EXTERNAL
BREAKER) AND DISCONNECTING
POWER CABLE FROM RECEPTACLE
J101 (120V RECEPTACLE).
Tag and disconnect wires to alarm horn.
Remove horn (18) by removing screw (15),
washer (16), and lockwasher (17).
Test. Connect 24V DC across terminals 1 and 2
of alarm horn. If horn does not sound, it is
defective and should be replaced.
Install horn (18) using screw (15), washer (16),
and lockwasher (17).
Connect wires and remove tags.
5-12. RELAYS MOUNTED ON REAR PANEL OF
CONTROL CUBICLE (54, figure 5-1).
Underfrequency relay 81GU (9, figure 5-19).
Test the underfrequency relay by connecting
as shown in figure 5-20.
Switch S1 closed.
Adjust variable frequency generator for 50
generator to 48.5 Hz. Relay should trip as
frequency is decreased. Ohmmeter will no
longer show continuity.