Onan MJA Series Service Manual page 98

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FIG 4. G - TYPICAL MAGNECITER CIRCUIT
4.1 ADJUSTMENTS
OUTPUT VOLTAGE. - It's possible, by means of controls in the mag­
neciter, to make small changes in the generator output voltage. DON'T
use these controls to increase generator output above the rated voltage
(i.e: 120 V, 240 V).
On models with an 02SX Magneciter (See nameplate) adjust the voltage
by changing the tap used on the control reactor, Cl' C2, or C3. The
voltage difference between each of the taps is abour 4% of the output
voltage and C 1 gives the highest voltage. At the factory, the connection
was made to C2'
On the 04SX and 06SX Magneciter, an adjustable tapped resistor controls
the voltage output.
It
is adjustable over a range of about 5 percent with
the highest voltage when the tap is moved to the top of the resistor.
4.2 MAINTENANCE
The generator normally needs little care other than periOdic inspection
of the exciter, ballbearing, collector rings and brushes every 1000
hours. However, 02SX exciters require build-up relay cleaning every
500 hours.
4.2.1 BRUSHES. - To examine the brushes, brush springs, and slip
rings, remove the exciter cover at the rear end of the generator. Note
that the exciter mounts on a hinged plate. Remove the screws from the
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