Transcript Charging System Service

Charging System
Service
Chapter 35
Page 459
Test the Battery First
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Make sure the Battery can be used to confirm
this
is fully charged or has the ability to be charged.
A DVOM and/or charger The Battery should be
12.6 volts
 The battery can have 13.0 volts – this is called a
surface charge, it can be removed by turning on the
headlights for 30 seconds
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Quick Voltage Check
Initial Checks
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Check for corrosion and intact wiring.
Wiggle wires while the engine runs. Keep an eye on the amps
reading. (inside gauge or amp meter)
Listen to noises from the alternator and belt area.
Check over the belt (the engine off, of course) for damage
 Try to make belt slip by
turning it manually.
 About an inch of deflection
over the longest span is good.
Bearing Locations
Noisy bearings is the most common complaint other
than the alternator completely failing.
Alternator Rating
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Cars up to the eighties needed about a 50 amp
alternator.
Cars in since the eighties have much more in the way of
onboard electronics so a 100 amp alternator.
Trucks have traditionally needed a more powerful alt. it
is not uncommon to see 125-200 amp alts.
If you add a bunch of electronics; amps CD, DVD, TV,
etc. you will have to upgrade the alternator and the
battery.
Alternator Testing
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There is four tests:
Charging system output- loads (creates a draw) the
system and checks amps output.
 Regulator voltage setting- Checks for minimum and
maximum settings.
 Alternator full field test- tests the max that the
alternator can put out.
 Charging circuit resistance tests- measures voltage
drop and loss of power to and from the alternator.
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Our Charger
This unit has a tester unit on top
and a charging unit below.
 This unit is able to test all four
alternator tests.
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Testing Precautions
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Connecting the test wires wrong can damage the
system.
Don’t full field the alt. for more than 10 seconds.
Don’t connect or disconnect components while engine
is running.
Don’t disconnect the regulator while the engine is
running.
Don’t operate the alt. without the wiring connected.
Using the Vat 45 is much safer for you and the system
than manual ways of testing.
Manually Full Fielding
Alternator Service
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Like the starter and other components on the
vehicle the repair is limited to replacement with
a few exceptions.
Changing the pulley and fan. Sometimes you
purchase a new alternator you have to use the old
fan and pulley.
 Rotor checks, Stator checks, diode test, brush, and
bearing work requires disassembly of the alternator.
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Testing Stator
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The different legs and from legs to iron core
should be open 1. on the ohmmeter. (isolated
form one another).
Testing Rotor
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Between the slip rings and the iron core there
should be 1. on the ohmmeter (isolated).
Between the slip rings there should be near .000
ohms or continuity (connected)
Testing Diodes
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A good diode will show high resistance in one
direction and infinity in the other (1. and .000)
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Remember it is a one way check valve.
Bad diodes will read open (.1) or low resistance
(.000) in both directions.
Voltage regulator
 To check them; just place
the leads to the DVOM and
take a reading, then reverse
the leads and take another
reading.
Positive Lead
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*Check each diode(3)
Negative Lead
Noisy Diodes
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Sometimes the radio picks up noise that sounds
like a siren that changes with rpm’s.
This indicates a bad diode, (sometimes the
sparkplug wires are to thin).
A bad diode may cause a growling or a whining
sound.
Adjusting the Belt
Your Job.
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Complete chapter Questions 1-10 (review) and
1-10 (ASE-style). Page 465
Write on a separate paper and write out the
complete question and your answer. ( do not
write the other answer options).
Complete the chapter worksheet (I will give it
out). You may write on it.
File all items in your note book.
Notebooks will be graded in the future.