OPX300K2 05/12
12
Maintenance
2. Replacement of Rotary Rectifi er Parts:
a. Rotary
rectifi er parts are all located at the rear
of Exciter rotor. For parts replacement, remove
the
bearing
shield.
b. To test the rotating rectifi er diodes, disconnect
the lead to the diode element and measure the
resistance between the anode and cathode on
each diode (see Figure 8).
Caution
: Do not overheat the diodes. If the resist-
ance value of the diode in the forward direction is
low and the reverse direction resistance value shows
infi nity, it is good. If this is not the case, the diode
element is defective and must be replaced. The diode
elements can be damaged if overtightened.
c. “J” type diode elements are fastened to the J(+)
side of the rotating rectifi er assembly, and “K”
type diode elements to the K(-) side.
Figure 8. Testing Diode Elements
d. The Diode Torque Specifi cations for all 300
series
models
is
5 mm = 48 in. lb.
e. In order to test whether the rotating rectifi er
assembly surge absorber elements are good or
not,
fi rst disconnect all lead wires as described
in
PARTS REPLACEMENT METHOD
, Point 2,
(above) and measure the resistance across surge
absorber elements with a tester.
• Good surge absorber elements have about 10-30 K
ohms, but if the resistance reading is near 0 ohms,
the surge absorber elements is defective and must be
replaced.
• Also, inspect outside of surge absorber and replace
if it is cracked.
• In addition, when installing surge absorber elements,
apply Loctite to the bolts.
3. Bearing Housing Replacement:
Inspect the O-Ring. If cracked, replace. Reassemble
carefully, aligning housing with bearing. Tighten
housing bolts to 2.5 kpm (18 ft/lbs.).
