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electrical charging and cranking > Charging testing service > Flashcards

Charging testing service Flashcards

1
Q

alternator drive belt in poor condition and not tensioned properly can

A

result in an undercharged battery

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2
Q

all belts are considered used when

A

they have been operating for more then 15 min

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3
Q

drive belt glazing is caused by

A

heat friction when a loose belt slips or oil/grease on the belt and pulley

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4
Q

separating layers

A

oil grease or belt design can cause the belt to fall apart in layers

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5
Q

Jagged or streaked side walls

A

can be the result of a foreign object embedded in the pulley drive surface

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6
Q

tensile breaks

A

are breaks in the belts cord body can be caused by prying or forcing belt over pulleys during installation

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7
Q

multi ribbed belts must be check for

A

uneven ribs in the belt

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8
Q

cracks in the belt

A

signs of an old belt

if the belt has evenly spaced deep bottom cracks means the idler diameter is to small and the belt is being over flexed

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9
Q

duel belts or matched belts

A

must be replaced together at the same time

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10
Q

when inspecting pulleys

A

hold a small straight edge against the side walls and check for worn groves and oil and grease build up if it cannot be cleaned it must be replaced

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11
Q

when checking belt tension

A

use a belt tension gauge

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12
Q

when working on drive belts you should always make sure

A

the batteries are disconnected to ensure the unit will not start

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13
Q

is a multi ribbed belt is slipping

A

check the belt tensioner is operating in the right range

if it is it may have to be replaced

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14
Q

alternator alignment

A

use a straight edge

pulleys must not be offset more than 1mm for every 20 cm of distance between the pulley centers

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15
Q

when should you check belt alignment

A

every time belt maintenance is preformed or alternators are being replaced

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16
Q

when mounting an alternator

A

use a minimum of grade 5 bolts with hardened washers no less than 3mm thick and flanged locknuts

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17
Q

when checking insulated and ground circuits

A

check for unwanted high resistances resulting in excessive voltage drops

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18
Q

if the alternator senses a false voltage created by unwanted high resistances

A

the units batteries will be under charged

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19
Q

when checking alternator and batteries circuits make sure to

A

not exceed the rated output of the alternator

if you do damage to the systems electrical components could be caused

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20
Q

why must you move quickly when using a carbon pile and a volt meter testing for voltage drops in a circuit

A

because the carbon pile will over heat quickly

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21
Q

if the the sum of the voltage drops is greater than _ in a 12 volt system it will not charge batteries correctly

A

.5 volt

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22
Q

if the sum of the voltage drops in a 24 volt system is greater than _ it will not charge the batteries correctly

A

1 volt

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23
Q

when preforming on unit electrical checks the components must be

A

at normal shop temperatures 16 to 23 degrees

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24
Q

symptoms of not completely charged batteries

A

slow or no engine cranking
low voltmeter reading
dim work lights
slow cycling of equipment warning lights

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25
symptoms of over charged batteries
voltmeter readings are high lights burn very bright or burn out rapidly batteries emits bad smelling fumes batteries spews out acid or swells or distorts
26
batteries can become sulfated if
they are undercharged due to unbalanced internal resistance
27
if batteries have become sulfated
will have less capacity to convert chemical energy into electrical energy
28
if batteries have an unbalanced internal resistance
they will be unable to crank engine during start up
29
before preforming any charging system diagnostics
check the battery group for proper charging and condition
30
when testing batteries for proper operation
must be properly charger as to not interfere with voltage and current readings
31
OCV of a battery group system is 12.8 or 25.6
batteries have a surface charge on there plates and it must be removed leaving the lights on for 3 min will remove surface charge
32
OCV of a battery group system is under 12.6 or 25.2
the batteries are undercharged and must be charged and re tested important to disconnect batteries from system to avoid component damage
33
when testing alternator regulator voltage under a no load condition
all electrical loads must be turned off set engine speed to provide maximum alternator output after 2 min record voltage reading
34
alternator regulator test results 13. 8-14.8 volts for a 12 volt system 27. 6-29.6 volts for a 24 volt system
regulator is set correctly
35
Alternator regulator test results less than 13.8-27.6 volts or more than 14.8-29.6 volts
regulator needs to be adjusted
36
the regulator must not be
30% more than the rated output
37
if the alternator is not within _ of the rated out put it must be replaced or repaired
10%
38
most common internal alternator faults
``` open field (brushes worn ) shorted stator open stator shorted diode open diode ```
39
effects of an open stator winding
amperage output will be greatly reduced
40
effects of a shorted diode
allows current to flow in both directions causing a large drop in alternator current output output may be reduced as much as 60 to 70 % could easily over heat
41
effects of an open diode
an open rectifier diode will produce a whining sound | current will be reduced by 33 %
42
when disassembling alternators
you may need to use special disassembly tools
43
when disassembling alternator housings never
use a hammer and a chisel to index the housing for orientation this will cause electrical insulation breakdown and distortion of the case
44
when removing the shaft nut on the alternator
hold the alternator with a strap wrench | do not hold the fan blades they can be easily damaged or warped becoming unbalanced and useless
45
if bolts in the housing are seized
you can carefully warm a localized spot on the case | jarring the bolts and applying penetrating oil will also help
46
if the drive end housing binds to the stator when removing
tap the aluminium case gently with a plastic or rawhide mallet
47
when checking the diode trio
use the DDM in diode check mode and check for a millivolt reading in forward bias meter should read OL in reverse bias
48
if any of the three diodes in the diode trio exhibit a short or open condition
the whole diode trio must be replaced
49
if a diode in the rectifier bridge exhibits a shorted or open condition
you can replace the individual diode
50
when visually inspecting the stator windings
look for signs of overheating or bare wires
51
when conducting a stator ground fault test and your multi meter reads (infinite ohms)
this indicates that the stator is not grounded
52
when checking for opens in the rotor windings connect each lead of your meter to the slip rings if your meter reads (OL)
there is an open in the windings and the rotor must be replaced
53
when checking for ground faults on the rotor your meter is connected to the slip ring and the metal components and your meter reads less than (OL)
the rotor has a ground fault and must be replaced
54
how do you check for shorts or excessive resistance in rotor windings
by connecting a battery and a ammeter in series with the surface of the two slip rings should also connect the volte meter in parallel to check for proper volt reading
55
if the rotor slip rings at dirty you can clean them with
400 or more grit sandpaper
56
why should you not use emery cloth to clean slip rings
because the metal particles can adhere to the rotor and cause premature brush wear
57
slip rings that are rough or out of round can be refinished | always make sure to be within _ of the total allowable runout
0.05 mm
58
if the rotor must be removed from the drive end housing
it must be pressed out | can be easily cracked because they are not designed to absorb axial load
59
when inspecting the brushes you should replace them when
they are worn over half or show signs of burning or cracked
60
if brushes are to be reused you must
rematch the wear pattern on the brush to the slip ring it was on
61
capacitors are tested for
capacity leakage series resistance
62
when testing a capacitor for leakage or series resistance you must use
a capacitor tester
63
why should you never soak the stator windings in petroleum based solvents
because this can dissolve the components insulation layer causing ground faults or electrical shorts
64
when using electrical contact cleaner it must not contain
silicone because it will attack the brush material causing short brush life
65
after reassembling an alternator you should
bench test it for proper operation
66
two types of sound to listen for when troubleshooting
electrical and mechanical
67
electrically generated sounds
will produce a whining noise that varies in intensity as the electrical load changes
68
mechanical sounds
do not change when extra load is placed on alternator
69
when changing voltage regulator settings
should be changed in steps of 1/10 of a volt and allow time for system to re-evaluate before changing again

electrical charging and cranking (5 decks)

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