Brushes; Avr (Automatic Voltage Regulator) - Robin America RGX305, RGX305D, RGX405, RGX405D, RGX505, RGX505D Service Manual

9-3 BRUSHES
The brushes must be smooth where they contact the slip
rings. If not, polish smooth the brushes with sandpaper. A
brush that is not smooth produces arcs between the brush
and slip ring leading to possible damage. Usable brush lengths
are from 5 mm to 15 mm as shown in Fig. 9 -4. A brush
shorter than 5 mm must be replaced because decreased con-
tact pressure between the brush and slip ring lowers genera-
tor efficiency and output voltage.
!15mm-5mm
15mm-5m
r
Fig. 9-4
9-4 AVR (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 ln the generator and operating it.
9-4-l AVR TROUBLE IDENTIFICATION by APPEARANCE
If an AVR electronic part is burnt dark, or the surface epoxy resin melted, it often indicates indicates AVR trouble.
9-4-2 IDENTIFYING AVR 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 tables below, the AVR is faulty.
NOTE: Take tester inaccuracy in to account in reading tie tester.
TESiER
Fig 9-5
-38-