Merc-O-Tronics 98 - TESTING SELENIUM RECTIFIERS; Selenium Rectifier Test Procedure

f
il
L
Figure 28
Figure 29
TESTING SETENIUM
RECTIFIERS
BY
MEASURING
DIRECT
CURRENT
RESISTANCE
1.
Set
selector
switch on
position
No.
3,
"Continuity".
2.
Clip
small red
and black test leads
together and turn
meter adjust'
ment knob for
Scale No.
3 until
meter
pointer
lines up on set
position
on
Scale
No. 3, right
side.
3.
Connect small
red test lead
to
positive
leadon rectifiers.
Figure
28.
4.
Connect small
black test
lead
to
ground
stud
or
lead on
rectifier.
Figure
28.
5. Note reading
of
figures
on
lower band, Scale No.
3.
6.
Reverse
test leads
on
rectifier
and
note readings again.
7.
Ratio of
two readings
should be
10:1 or
greater.
8.
Remove analyzer test leads and connect to the
two alternator
leads
or
lead terminals
on
rectifier.
Figure
29.
9.
Note reading
of
figures
on
lower
band,
Scale
No.
3.
10.
Reverse test leads on rectifier
and
note readings again.
11.
The
ratio
of the two readings
should
be
no more than
2:1.
L2.
This is
only a
preliminary
test to determine
eondition of
rectifier.
If
questionable,
as a
final test, rectifier should be
installed on engine
and checked
with
ammeter
while
engine
is
running.
NOTE: This is a
true
ohm scale,
0
-
200,000
ohms
and can
be used to
test ohm
resistance
of other
electrical
components.
2.4