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PART
13-5-ALTERNATOR REGULATOR
13-29
ZENER DIODE LEAK CIRCUIT
At high temperatures, a
small
leakage current may flow through
the Zener
diode
even though
the
latter is in the
nominally non-con-
ductive state.
Resistor R6 provides
a
path
for this leakage current
which
otherwise
would flow through Tl
base
circuit and adversely
affect the
regulator
action.
IN CAR TESTS AND
ADJUSTMENTS
Before attempting to assess the
performance
of the
voltage regulator
always carry out an alternator
out-
put
test. See
page
13-7.
The
voltage
regulator tests must
be carried out with a fully charged
battery and with the regulator at
normal operating temperature.
Before
carrying out
the tests
ensure that all wiring and connections
in the charging circuit (including
battery terminals) are tight and in
good condition.
Voltage Regulator Test 9
ATR and
13 ATR.
1. Connect a voltmeter across the
battery terminals.
2. Connect a 0.60 amp ammeter
in series with the alternator main ( +)
lead.
3. Connect a carbon pile rheostat
or switched lamp bank across the
battery terminals (Make sure
controls
are in the out or off position).
4. Connect a tachometer to the
engine.
5. Start the engine and adjust
speed to 1000 R.P.M.
6. Adjust charge rate to 11 amps
and allow the engine to run at this
rate for 10 minutes.
7. Increase engine speed
to
give
6000alternator R.P.M.
(see
chart)
and
adjust charge rate to 11 amps.
8. The
voltmeter should now
register 14.3
±
0 .4 volts.
Both
the 9 A TR and 13 A TR reg-
ulators
are
non-adjustable
units
therefore if the test figures are
not
achieved the regulator must be
re-
placed.
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