Session 7: Circuit Diagram of Starting System of Automobileand Checking of Starter Circuit
Module 5: Auto Electrical System
Textual Question-Answers
Check Your Progress
Fill in the blanks
1. The starter motor converts electrical energy into …………….
motion to crank the engine.
Ans: mechanical
2. To check the continuity between the terminal lead and the brush,
a continuity test is performed using a ………………Ans: multimeter
3. If the commutator is rough or worn, it can be smoothed using………………paper.
Ans: emery
4. In the event of no cranking and dim lights, a possible cause couldbe an ………………circuit in the switch.
Ans: open
5. A weak shift lever return …………….. slowly after the enginehas started can lead to the pinion disengaging.
Ans: spring
Multiple Choice Questions (MCQs)
1. The electric starter system of an automobile includes which ofthe following components?
a) Alternator, carburetor, spark plugs
b) Battery, ignition lock, starter motor
c) Radiator, transmission, throttle body
d) Exhaust pipe, fuel pump, brake pads
Ans: b) Battery, ignition lock, starter motor
2. What is the purpose of the Bendix pinion in the starter system?a) To generate electricity
b) To engage the gears in the transmission
c) To rotate the crankshaft
d) To engage the starter motor with the engine’s flywheel
Ans: d) To engage the starter motor with the engine’s flywheel
3. The armature in the starter motor is primarily responsible for:a) Controlling the ignition timing
b) Holding the brushes in place
c) Converting electrical energy into mechanical motion
d) Regulating fuel flow to the engine
Ans: c) Converting electrical energy into mechanical motion4. Excessive resistance in the cranking motor circuit can result in:a) Bright lights
b) Faster engine cranking
c) Slow engine cranking
d) Overheating of the starter motor
Ans: c) Slow engine cranking
5. In a starter system, the solenoid plunger chattering is often causedby:
a) Low battery voltage
b) A defective ignition system
c) A short circuit in the control circuit
d) Overheating of the starter motor
Ans: a) Low battery voltage
6. What is the purpose of the over-running clutch in the startersystem?
a) To engage the Bendix pinion
b) To regulate fuel flow to the engine
c) To prevent the starter motor from overheating
d) To allow the engine to start even after the starter motor disengagesAns: d) To allow the engine to start even after the starter motor disengagesAnswer the following questions
1. Share importance of circuit diagram of starting system ofautomobile and checking of starter circuit in a vehicle.
Ans: The circuit diagram of the starting system helps in understandingthe arrangement and connection of components such as battery, ignition switch,
starter relay, solenoid, and starter motor. It helps in diagnosing faults quickly.
Checking the starter circuit ensures reliable engine starting, prevents damageto components, and improves vehicle safety and performance.
2. Draw the circuit diagram of starting system of an Indian car.
Ans: The starting system circuit includes the battery connected to theignition switch, starter relay, solenoid, starter motor, and ground, forming acomplete circuit to crank the engine.
3. Explain the procedure of checking the starting circuit.
Ans: First, check the battery condition and terminal connections. Inspect
the wiring and ground connections. Turn the ignition switch to the start positionand observe cranking action. Measure voltage at the starter motor using avoltmeter. Check solenoid operation and continuity of the circuit to locatefaults.
4. Write different faults may occur in the starting circuit, their causesand remedies.
Ans: Common faults include no cranking due to a discharged battery oropen circuit, slow cranking caused by excessive resistance or weak battery,
clicking noise due to faulty solenoid or low voltage, and starter motor runningcontinuously due to defective switch or relay. Remedies include charging orreplacing the battery, tightening connections, repairing wiring, replacing faultysolenoid, relay, or starter motor.
Activity
1. Make a list of faults in starting system of a vehicle, their causesand remedies.
Ans:
1. Fault: No cranking
Causes: Discharged battery or open circuit
Remedies: Charge or replace battery, repair wiring
2. Fault: Slow cranking Causes: Weak battery or high resistance
Remedies: Clean terminals, replace battery
3. Fault: Clicking noise
Causes: Faulty solenoid or low voltage
Remedies: Replace solenoid, charge battery
4. Fault: Starter runs continuously
Causes: Stuck relay or ignition switch
Remedies: Replace relay or switch
2. Prepare a poster showing main component of starting system ofa vehicle.
Ans: The poster should show the battery, ignition switch, starter relay,
solenoid, starter motor, Bendix pinion, flywheel, and connecting cables clearlylabeled.
Try youself
