Figure 15-2. Synchroscope, Test Setup
the incoming' must then be inched up or down until the
pointer takes a steady position at 12 o'clock.
c. Replacement. The synchroscope is mounted on
the remote control module control panel.
Disconnect and tag wires and remove attaching
hardware to remove the synchroscope from the
15-8. RELAYS. Test and replace undervoltage relay
K115 and underfrequency relay K116 as follows:
(1) Undervoltage relay K115 (2, figure 15-3).
(a) Connect relay as shown in test
setup figure 15-4.
(b) Connect a variable 0 to 160V AC
source and variable frequency (50
to 60 Hz) source to terminals 1
and 2 with switch S1 in series.
(c) Connect lamp DS1 and 24V DC
power supply in series with switch
S2 to terminals 3 and 4, also with
terminals 7 and 8 (DS2).
(d) Adjust AC power supply to 120
volts, 60 Hz. With Sl and S2
closed, lamp DS1 should extinguish
and DS2 should light.
(e) Reduce voltage slowly to 104 volts
and hold for 2 minutes. Lamp
DS1 and DS2 shall maintain
(f) Reduce voltage to 99 volts. DS1
and DS2 shall transfer states
within 4 to 8 seconds.
(g) Increase voltage slowly to 113
volts. Lamps DS1 and DS 2 shall
(h) Reduce voltage to 48 volts.
Transfer of states of DS1 and DS2
shall be instantaneous
(i) Reduce frequency to 50 HZ and
repeat the procedures in steps