The flashcards below were created by user
Ordonez
on FreezingBlue Flashcards.
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Counter Electromotive Force is:
Voltage produced by the armature spinning in a magnetic field.
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The slower the an armature rotates:
The more current it draws.
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If a load on a series motor is suddenly removed:
its speed keeps increasing until it self-destructs.
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To change the direction of rotation on a parallel motor, you must reverse: (2 answers)
the direction of current flow in the armature.
the direction of current flow in the field windings
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While testing a starter armature, if u place one ohmmeter lead on the commutator bars and the other lead on the armature shaft and the ohmmeter reading is infinite, the armature:
is testing normal
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If you are testing an armature using a Growler and the metal strip held above the armature windings begins to vibrate, the armature:
is shorted.
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Scoring or rub marks on the laminated iron core of the armature can be caused by: (3 answers)
- a bent armature shaft
- loose field pole shoes
- worn bearings or bushings
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How to check a one-way clutch ? (direction)
Hold the starter drive in one hand while rotating the drive gear in both directions
In one direction - it should hold and not slip; in the other direction, it should turn with some resistance.
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What causes burning of the commutator bars ?
loose connections or poor connections - can also cause arcing of the commutator bars.
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What causes an "Open" Armature Winding ?
Opens are causes by excessively long cranking times.
Check for hard starting problems that may have contributed to this failure.
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If the commutator bars are black or the windings are discoloured where they are connected to the commutator you should ?
replace the armature.
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How are "Short-Circuits" located in the Armature ?
are located by rotating the armature in a Growler (armature tester) w/ a steel strip such as a hacksaw blade held on the armature.
Steel strip vibrates as the shorted circuit passes below the steel strip.
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How are grounds check on an armature ?
checked with Ohmmeter
place one lead on the commutator bars and the other on the armature shaft.
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How do "Grounds" occur on the armature ?
Grounds occur as a result of insulation failure
which may hav been brought on by overheating of the cranking motor.
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Never use _________ to clean the commutator.
emery cloth.
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First step in any starter removal procedure is to remove the:
negative battery cable first.
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Field Coil tests can checked for ________ and _______ by using an _________.
Grounds, Opens, Ohmmeter.
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When checking for Ground on Field Coils, where are the leads connected ?
Connect one lead of the ohmmeter to the field frame and the other lead to the field connector.
if the ohmmeter reads "infinity", the field coils are NOT grounded.
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How do you test for "Opens" on field coils ?
Connect the ohmmeter leads to each end of the field coils, if the reading is open (infinity) the field coils hav an "Open" circuit and must be replaced.
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How do you test for "Shorts" on field coils ?
Due to low resistance of field coils, there is no test for 'shorts'
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Relays can be tested for:
proper resistance across the solenoid coil and a voltage drop not exceeding 0.2 volts across the contacts.
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What can cause a no-crank condition ? (3 answers)
- open neutral safety switch
- open clutch switch
- activated anti-theft system
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A starter motor current draw test measures the __________.
actual current flow required to crank over the engine
make sure to disable the ignition system (or fuel system)
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