Hobart 5359D Operation And Maintenance Manual page 128

OM 2012
It may be necc NQTE:
ssary to switch to MANUAL contrcl to obtain thc:re
low voltages.
(c) If the load contactor is not opened at 103 \I to 93 V, it will be necessay
to refer to the Troub!e Shcoting Chart, Section 3-1, to d&ermine
which
COV~OilCtlt
of the undervoI:uge protective circuit is defective.
(d) If the undervoltage circuit performs satisfactorily, return the unit to norma!
operaticn by adjusting the voltage to 115 V, pressing the reset switch, and
closing the foad contactor.
(40) c!eck
d is 'I
un c *rc uency sensing relay, protective monitor, and indiccjting light.
At some frequency value (Hi:, cyc!es-per-second) from 385 Hz down to 375 Hz,
the underfrequency sensing relay should function to signal the underfrequency
circuit'in the protective monitor module to OPEN the load contact07 holding
"
circuit, thus OFENING the load contactor. To check the underfre.quency
*
. ,protoctive components, proceed as follows:
la) Whi !e the unit is. operat ing normally under load, reduce ,generator output
frequency. by reduding engine speed. Use the governed speed setting
potentiometer (Ref. Fig. 12). Turn adjusting screw COUNTERCtOCKWlSE
gradually to reduce engine speed until frequency meter indicates 386 Hz.
Underfrequency protective relay should not function to open the load con-
tactor at this frequency. Reduce frequency in steps of 1 Hz.
.jb) ff the protective system functions to open the load contactor and turn on
the underfrequency light after sarnf: frequency between 385 Hz and-375 Hz
is reached, all components of the system are functioning properly.
If the
load contactor is not opened with in the above frequency range, refer to
Trouble Shooting Chart to determine which component is defective.
(c) Return unit to normal operating condition.
(41) Check overfrequency sensing.relay, protective monitor, and indicating light.
2-3
Aug 25/85
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