Hudson 1955 Rambler, Техническое и сервисное руководство

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E L E C T R I C A L
37
FIGURE 39— Oil Pressure Warning Light
Test Procedure
the storage battery or charging circuit and
regulate it to a constant value for the
single wire gauge circuit shown schemati-
cally in Figure 40.
FIGURE 40— Fuel and Temperature Gauge
Circuit "Hornet" and "Wasp" Series
To produce the constant voltage 5.0 volts
output, the regulator is constructed simply
as a heater bi-metal in conjunction with a
pair of contacts. It is temperature compen-
sated to produce correct constant voltage
for the gauge systems at all expected
temperatures. It is mounted near the dash
panel indicators at approximately their
same temperatures. The voltage regulator
does not produce a steady D.C. voltage output,
but rather a pulsating voltage at an effective
constant average value of 5.0 volts.
The input voltage source can, therefore,
be D.C. intermittent or interrupted D.C. or
A.C. just as long as the average input voltage
does not drop below 5.0 volts. Input voltage
lower than 5.0 volts will result in propor-
tionately low gauge indication. With the
constant voltage regulator operating properly
(with input voltage normally varying from 5.6
to 8.0 volts) input voltages in excess of 8.0
volts will not affect gauge indication accu-
racy but will overload the regulator contacts
and may result in premature wear.
Fuel Level Gauge Operation
"Hornet" and "Wasp" Series
With the tank empty, the float holds the slide
rheostat (variable resistance) at maximum
resistance causing the gauge to read "empty"
(Fig. 41).
FIGURE 41—Tank "Empty" Position
With the tank full, the slide rheostat is
moved to the minimum resistance point causing
the gauge to read "full" with the ignition
switch on (Fig. 42).
Temperature Gauge Operation
"Hornet" and "Wasp" Series
The temperature gauge sending unit is a
thermistor which varies in electrical conduc-
tivity with change in temperature, being very
high in resistance when cold and low in
resistance when hot.
The schematic drawings (Figs. 43 and 44) show
the operation of the temperature gauge system.
Testing the Gauge Units
"Hornet" and "Wasp" Series
If both gauges read excessively high such as
fuel gauge reading high level when actually
low level exists or temperature gauge reading