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5.
The half
assembly having white leads
on
the diodes contains three "Forward" stud type diodes, and the
half
assembly having black leads on the diodes contains three "Reverse" stud type diodes.
The diodes may
be
tested in the field without removing them from the heat sinks. Electrically isolate
the individual diodes by removing each
of
exciter
rotor
lead flag terminals from the quick c01:nect
diode terniinals, and remove the
two
main
rotor
leads from the main rotor terniinal posts. Test each
sub-assembly separately.
An ohmmeter
or
a battery light continuity tester may
be
used
to
finci
an
open
or
shorted condition in the diode. Place one tester probe on the main post.
In
successio::. touch
the other test probe
to
each diode terminal. Reverse the probes and repeat
the
procedure. Y m have
now tested the three diodes
on
this sub-assembly. Repeat the test on the second sub-assembiy.
These tests should indicate one
ofthree
conditions:
(1) Good diode:
Will
have a much greater resistance in one direction than the other. Typical
reverse resistance will be
30,000 - 300,000 ohms
or
greater, while typical forward resistance will
be
less than
10
ohms. The battery-light tester will have the light "on" in one direction, and "off" in the
other.
(2) Shorted condition: Ohmmeter reading will
be
zero,
or
very low in both directions. The
continuity tester will have the light
"on" in both directions.
(3)
Open condition: Ohmmeter will have a maximum (infinity) reading in both directions.
Continuity tester light will be dark
(off) in both directions.
Figure 5. ROTATING RECTIFIER ASSEMBLY
MAIN
ROTOR
LEAD
WHITE
LEADS
FROM
EX.
RTR.
TO
CONNECT
TO
RECTIFIER
ASSY.
WITH
WHITE
LEADS
I
//i~TI--l\-_;
1
t+-_MAIN
ROTOR
LEAD
J
/
/
MOUNTING
SCREW
TORQUE
TO
40-50
IN.LBS.
BLACK
LEADS
FROM
EX.
RTR.
TO
CONNECT
TO
RECTIFIER
A5SY.
WITH
BLACK
LEADS
-----=
--
BLACK
POST
14
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