Adjustments and Settings
Solid State Timers
Solid state timers are adjustable from 0.1 second to 100
hours. The red timing indicator in the upper left corner
flashes as the timer progresses through the timing cycle.
When the timing cycle is completed, the indicator
remains illuminated. A flathead screwdriver is required to
change the setting, as shown in Figure 30.
The time unit is selected by turning the rotary switch at
the lower right of the timer. Four selections are available:
“Seconds”, “Minutes”, “Hours”, “10 Hours”. The time
unit selected is displayed in the window below the time
setting dial.
The time range is selected by turning the rotary switch
at the lower left of the timer. Four ranges are available:
“0-0.5”, “0-1.0”, “0-5.0”, “0-10.0”. The dial digits appear in
the windows around the time setting knob.
Figure 29
CAUTION
Do NOT change the setting while the timer is energized. Timer malfunction or damage may occur.
The factory setting of the solid state timers used in the
Zenith standard package are shown in Table 4.
Timer
Factory Setting
T
30 minutes
U
5 minutes
W
1 second
Table 4
Voltage/Frequency
Sensor (VFSM)
The “restore” or pickup point may be adjusted by
rotating the adjustment screw as shown in Figure 31.
Counter-clockwise rotation increases the pickup voltage.
“Restore”/Pickup Voltage (at 100% Frequency)
Adjustable: 80% to 95%
Factory Set: 90%
“Restore”/Pickup Frequency
Adjustable: 80% to 100%
Figure 30
Factory Set: 95%
Solid State Phase Relay
(ARSM)
The “restore” or pickup and “fail” or dropout points
may be adjusted by using the following procedure.
Use of a variable voltage supply (Variac) is required.
The relay is illustrated in Figure 32.
1. Turn the “restore” or pickup adjustment
fully clockwise.
2. Turn the “fail” or dropout adjustment fully
counter-clockwise.
3. Set Variac to the desired “restore” or pickup voltage.
4. Rotate the “restore” or pickup adjustment counter-
clockwise very slowly until the relay picks up.
The LED will illuminate.
5. Set Variac to the desired “fail” or dropout voltage.
6. Rotate the “fail” or dropout adjustment clockwise
very slowly until the relay drops out. The LED
will go out.
7. Verify the setting by raising the voltage until
the relay restores or picks up and lowering
the voltage until the relay fails or drops out.
“Restore”/Pickup Voltage:
75% to 115% of Nominal
Factory Set:
90% of Nominal
“Fail”/Dropout Voltage:
55% to 105% of Nominal
Factory Set:
80% of Nominal
Figure 31
GE Zenith Controls
ZTS/ZTSD/ZTSH/ZTSDH/ZTSDL/ZTSHL/ZTSDHL Operation and Maintenance Manual (71R-3000)
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