Starting Systems Flashcards
How much amperage does a 4 cylinder starter take?
100A
How much amperage does a 6 cylinder starter take?
150A
How much amperage does a 8 cylinder take?
200A
What is the purpose of the starter?
Turns the crank until it can operate on its own
What is the average starter to engine gear ratio?
15:1 to 20:1
what RPM does the starter pinion gear turn at?
2500rpm to 3000rpm
what RPM does the flywheel turn at?
150rpm to 200rpm
what is CEMF?
Counter Electromotive Force traveling backwards towards the battery
What components are part of the Control Circuit?
Ignition switch, Safety switch, starter relay and battery
What components are part of the Starter Circuit?
battery, starter motor and starter solenoid
How many amps to pull in the starter solenoid?
35A
How many amps to hold in the starter solenoid?
10A
what is the preferred test to locate resistance in a starter circuit?
Voltage Drop (Voltmeter)
What is the rotating part of a starter called?
The Armature
What type of starter motor produces high torque at low RPM, and less as RPM increases?
Series
What type of starter motor has less torque at low RPM and higher as RPM increases?
Parallel / Shunt
What type of starter motor is able to handle torque at any RPM?
Compound
What are the 2 types of starters?
Positive Engagement & Solenoid Actuated
What are the 2 main components to an Armature?
windings & commutator
What is a Commentator made of?
Heavy copper segments (bars) that are separated from each other by insulation (mica)
Newer starter motors may use what kind of gear setup that allows the assembly to be smaller?
planetary gearset
What is the component of the armature where it receives its heavy current from?
The Commutator
The segments of the commutator should have what type of resistance between themselves?
Low resistance & similar from bar to bar
What 3 methods ensure that the pinion gear is able to engage the ring gear smoothly?
Beveled teeth, Spring behind the pinion gear & Bendix drive
What could cause a Low current draw?
Undercharged battery
What could causes high current draw?
Resistance in the motor
What is an maximum Voltage drop across connectors?
0.1v
What is an maximum Voltage drop across a Starter relay?
0.3v
How do you check the starter drive to ring gear clearance?
feeler gauge or wire, if its less/more then 0.5cm (0.02”) it is defective
When performing a bench test, what could be the cause of a slow speed/high draw?
Physical resistance (bearings, short in armature, bent armature)
When performing a bench test, what could be the cause of no current draw/no crank?
Open in one of the circuits, broken brushes/springs
When performing a bench test, what could be the cause of low RPM/low current draw?
High internal resistance (bad connection/brushes)
When performing a bench test, what could be the cause of high RPM/high current?
Field windings shorted
What should never be used to clean the starter motor and why?
Solvents, the residue left on parts can ignite
What should be used to clean the starter motor?
Denatured alcohol or Compressed air (25psi)
what is a cranking voltage test, and how do you perform it?
Measures the available Voltage to the starter during cranking. it is performed by disabling the fuel or bypassing the ignition switch and connecting a Voltmeter to ground and starter feed. activate the starter and observe that the voltage has a minimum of 9.6v
what is a cranking current test, and how do you perform it?
Measures the amount of current the starter draws to crank the engine. it is performed by using a Inductive pickup clamp. Disable fuel and crank the engine for max 15sec and observe that the amperage is around 130A to 250A (depending on engine size)
