Underfrequency Circuit

TB 9-4920-359-35

(4) Adjust R119 (fig. 3) for a frequency counter indication of 1000 ms (R).

(5) Adjust R7 (fig. 3) for a frequency counter indication of 3.0 s (R).

Figure 3. Test instrument - front view.

13. Underfrequency Circuit

a. Performance Check

(1) Set dc power supply to OFF and disconnect frequency counter from equipment setup.

(2) Press multimeter ACV key and connect to J5 UFCAL.

(3) Set dc power supply to ON.

(4) Set TRIP TIME START switch to off (down). Multimeter will indicate between

10 and 15 V ac.

(5) Press multimeter FREQ key. If multimeter does not indicate between 1145 and

1165 Hz, perform b (1) below.

(6) Set TRIP TIME-START switch to on (up). If multimeter does not indicate

between 1085 and 1105 Hz, perform b (2) below.

(7) Press multimeter ACV key. Multimeter will indicate between 10 and 15 V ac.