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OM-2032 / Operation and Maintenance Manual
100D20 / Generator Sets
Protective Circuit (Continued)
Trouble, Symptom & Condition
Load contactor opens during
power delivery. Overvoltage
indicating light ON.
2. Load contactor opens during
power delivery. Undervoltage
indicating light ON.
Chapter 3-1
Page 24
Probable Cause
b. Defective over-under
-voltage sensing module
(K26).
a. An undervoltage condition
caused the over-under-
voltage sensing module
(K26) to function normally.
b. Defective over-under-
voltage module (K26).
c. Defective protective
monitor module (K14).
Corrective Action
Use voltage adjusting rheostat
(35, Fig. 1) to reduce voltage to
110-V AC. Observe voltmeter and
gradually increase voltage with
rheostat. If the over-under-voltage
sensing module (K26) functions to
open the load contactor at any
value less than 130-V AC, it is
defective. Replace
over-under-voltage module or
complete protection relay tray.
Observe generator voltage on
voltmeter and adjust to normal
115-V AC with voltage regulator
adjustment potentiometer (35,
Fig. 1). Resume normal
operation. If the load contactor
opens again and an under-
voltage condition is indicated by
light (DS38) proceed to step B.
Use voltage regulator adjustment
potentiometer(35, Fig. 1) to
reduce voltage to 104-V. Wait
12 seconds. The undervoltage
indicating light should NOT be
turned on. If the light is turned on,
the undervoltage relay is
defective. Replace the module
(K26) or the protective relay tray.
With unit running normally, use
voltage regulator adjustment
potentiometer ( 35, Fig. 1 ) to
reduce voltage quickly to 90-V. If
the undervoltage indicating light
(DS38) is turned ON immediately,
the protective monitor circuitry is
defective. Replace the protective
monitor module (K14) or the
protective relay tray.
March 31/94 Revised
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