Fiat 411 R Service Manual page 56

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Fig.'i5I1. - Electrical diagram oithe arrangement for settlng
the cut-out relay.
B,. 2V battery - B2. 40V battery » A. Ammeter, 20A iop
rerxriing {I% accuracy} - V. \/olimeter, 30V top reading
(0.5% accuracy, class) connected across terrninais 51 and 31 -
P. Potentiometer, volrage acfiusting; capacity must be such
that the I:ut~ou'£ reiay shunt winding coil consumption does
not create notab§e variations oi the no~Ioad vcléage measured
by the voltmeter ~ S. Warning Iight indicating opening and
closing of contacts (2 V-3 W bulb) - R. Rheostat 4 ohm -
213 A - R1. Drop resistance sufiIcient to allow lighting up oi
the warnings, Iighrs S by switch T1 with the cu?-out reiay
contacts ogxen.
W m
Voltage regulator setting. '
31 ||.
SI 67 39 '
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Fig. 'IE1. - Electrical diagram for setting the voltage and
current reguiators.
G. Generaior DC I15/24/7,l3 and its versions - V. voltmeter,
30 V Iop reading (0.5% accuracy cIass} - A. Ammeter, I0 A
top reading ~ R. Rheostat, 3 ohm-20A - B. 12 'I! - 190 Ah
batteries connected In series, I'uI%y charged - I. Switch.
Current regulator seiting.
106
once thermally stabilized, firing the I/oliage lo 25.1
to 25.9 V through potentiometer P;
adjust the load on the calibration spring (3, Fig. '$53)
by bending its rneial tongue (5) unfil the light S
goes out;
bring poieiiomefer P setting back to the minimum.
increase the voliage again acting once more on the
pofenfiomeier and check fhaz' the light' S goes out ai
the specified setting.
The contact points emflre closing stroke shoulci occur
at a voltage variation lower than 0,2 V.
2) Reverse current (at a temperature of 25°_-'-; 10° C
= rrfl i 50» F).
This test rnusi immedia1'ely follow the preceding one
in order to take advantage of the thermal sfabiliiy
achieved by the unit.
With switch T closed, bring the voltage lo 27 If by
acting on the potentiometer F' "(the cut-out relay
contact points are closed and light S ofi',I;t1'ose switch
'P, increase the reverse current through the rheoslat
R. and check that the light S goes on when the
contact points open. The opening may result to be
unstable eviclenceo' only by a ringing noise;
chock the ammelar reading of the reverse current
which starts the confacts opening (6 to I4 A}.
Should the reading be uncertain or should the lighi
go on like iolerance limit, bring the reverse current
back to minimum and increase if again working on
the rheosiat R, as instructed before;
open switches T and T1 and bring the sliders of the
potentiometer F' and rheostat R back to minimum.
Provide the conditions suitable lo mainiain the unil
at a temperature of 50°;I; 3° C (7221 37° F).
After wiring the unit according to the diagram of
Fig. '£61, wind {he adjusfing spring of the current
regulator by shaping the adjusting fongue (5, Fig. 152);
close switch I, star! the generator and stabilize the
lemperalure of the unit, for 30 minutes, af 2 30 V.
by varying the generafor speed;
open the swiich I and bring the generator speed up
lo 3500 R.P.lI/l.; adjust [he load of the adjusting
spring of the voltage regulator by bending the
tongue, and the rheoslat R, so to obtain a regulaiing
voltage and a medium charge current of 28.7 to
29.7 V and 5 A, respectl:/ely;
check stability and accuracy of the regularfion voltage'
by sr'o,oplng the generator and running ii again up
to the speed of 3500 R.P.M.
This test musi immediately follow the preceding
one, holding the fest temperature at 50°i3°C
(l22°i 37° F), and using the same instrumenis and
the same wiring diagram (Fig. 161);
close the switch I, start the generator, adjust its
speed and rheosfai R £0 obfain a volfage and a current
of 28 I-' and 5.-5 to 7.4 A., respecEive!y,'