Brushes; Avr (Automatic Voltage Regulator) - Robin America RGX180 Service Manual

9-3 BRUSHES
The brushes must be smooth where they contact the slip
rings. If not. polish the brushes smooth with sandpaper. X
brush that is not smooth produces arcs between the brush
and slip ring leading to possible damage. Usable brush lengths
are from 5mm to ljmm as shown in Fig. 9-3. .a brush
shorter than 5mm must be replaced because decreased con-
tact pressure between the brush and slip ring lowers genera-
tor efficiency and output voltage.
15mm - 5mm
Fig. 9-4
9-4 AUR (AUTOMATIC VOLTAGE REGULATOR)
AVR trouble may be identified -by simply looking at the AVR, or by checking the inter-lead resistance with a tester. or actu-
ally mounting it in the generator and operating it.
9-4-l AUR TROUBLE IDENTIFICATION by APPEARANCE
If an AVR electronic part is burnt dark. or the surface epoxy resin melted, it often indicates .r\VR trouble.
9-4-2 IDENTIFYING AUR TROUBLE by CHECKING
INTER-LEAD RESISTANCE
Check the inter-lead resistance of the AVR with a tester.
(See Fig. 9 -5 .) If the tester readings vary greatly from the
values specified in the Table 9-I. rhe AVR is faulty.
NOTE: Take tester inaccuracy in to account in reading the tester.
TESTER
Fig. 9-5
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