Automotive Technology: A Systems Approach Chapter 18

flux field

a magnetic field

flux density

increased by increasing current

reluctance

the resistance that a material offers to the passage of magnetic flux lines

starter housing

encloses the internal parts and protects them from damage, moisture, and foreign materials

field coils

securely attached to the inside of the housing

brushes

permits all current passing through the field coil circuit to also pass through the armature windlings

armature

the rotating part of a starter

commutator

mounts to the armature shaft

end frame

a metal plate that bolts to the commutator end of the starter housing

counter electromotive force (CEMF)

explains the relationship between current draw and motor speed

starter relay

two positive cables are needed

pull-in winding

draw the plunger into the solenoid, while the lighter-gauge winding produce enough magnetic force to hold the plunger in this position

pinion gear

the pinion teeth line up with the flywheel teeth and the spring pressure forces them to mesh

starting safety switch

normally opens switch that prevents the starting system from operating when the transmission is in gear

cranking voltage test

measures the available voltage to the starter during cranking

cranking current test

measures that amount of current the starter circuits draws to crank engine

growler

armature tester

pulse width modulation (PWM)

controls the current to the various stator windings

duty cycle

the length of time the device is turned on compared to the time it is off

asynchronous motors

in an induction motor, the rotor just rotate at a speed slower that that of the rotating magnetic field

slip

directly proportional to the load on the motor

inverter

used to change the battery's high-voltage DC into high-voltage, three-phase AC to power the electric motors

The starter must never operate for more than sixty second at a time and should rest for two minutes between extended cranking

False

The starter circuit requires strong voltage, but actual current flow is low

False

Cranking problems may occur if oversized battery cables are installed

False

Which of the following is NOT part of the starter motor circuit

Ignition switch

Which of the following could result in a hard starting condition

Corroded battery cables

When the starter spins but does NOT crank the engine, which of the following may be a cause

A defective starter drive

The usual minimum cranking voltage specification is ___ volts

9.6

While the engine is cranked, a voltmeter placed between positive battery post and the positive post of the starter reads less than .01 volt. The cause of this reading could be

Normal resistance in the positive battery cable

If a ground circuit test reveals a voltage drop of more than 0.2 volt, the problem may be a

All the answers are correct

A cranking current test is preformed, and the amperage is found to be less than specification. Tech A says the starter is bad and it should be replaced. Tech B insists on testing the resistance of the cables, grounds, and connections. Who is correct?

B only

An engine cranks slowly. Tech A says a possible cause of the problem is low resistance in the starter circuit connections. Tech B says a possible cause is an open in the starter field coil circuit. Who is correct

Neither A nor B

Tech A says the starter solenoid mounts directly on top of the starter motor. Tech B says the starter solenoid pushes the starter drive pinion into mesh with the flywheel teeth. Who is correct

A only

Checking for excessive resistance in the starting circuit is being discussed. Tech A says connecting a voltmeter across the ground cable from the battery to the ground connection of the cable is the preferred method. Tech B says connecting an ohmmeter across the positive battery cable after it has been removed from the vehicle is the preferred method. Who is correct

A only

Pinion gear to flywheel ring gear clearance is being discussed. Tech A says if there is too much clearance, there will be a high-pitched noise after the engine starts. Tech B says if there is too little clearance, there will be a high-pitched noise while the starter is cranking the engine. Who is cou

Neither A nor B

Tech A says the purpose of the solenoid is to engage the starter pinion into the flywheel's ring gear. Tech B says the solenoid energizes the starter motor by closing the electrical circuit from the battery to the motor. Who is correct

Both A and B

The teeth on a starter drive are worn excessively. Tech A says to replace the starter drive. Tech B says to check the flywheel. Who is correct

Both A and B

Tech A says the starter circuit carries high current from the battery to the starter motor. Tech B says the control circuit is a low current circuit that sends current from the ignition switch to the starter relay or solenoid. Who is correct

Both A and B

The starter solenoid's function is to

Both A and B

The function of the overrunning clutch in the starter drive is to

Prevent damage to the armature if the starter stays engaged after the engine starts

The pull-in winding and the hold-in winding are part of the

Starter solenoid

A vehicle is being diagnosed for a " no crank problem". When the ignition switch is turned to the start position, a clicking [buzzing] noise is heard at the starter but the engine does not crank over. Tech A says the problem could be a weak battery. Tech B says the problem could be an open in the hold-in winding. Who is correct

Both A and B

When performing a cranking current test: if a remote starter switch cannot be used, ___ system must be disabled

Fuel

The maximum voltage drop for the insulated circuit (battery positive to starter solenoid) is typically about ___ volt

0.6

The starter safety switch on a vehicle with an automatic transmission is typically located on the transmission housing.

True

The gear ratio between the starter pinion gear and flywheel teeth provides an increase in torque and a reduction in speed (rpm).

True

Some starters use planetary gearsets for gear reduction.

True

The starter circuit requires strong voltage, but actual current flow is low.

False

Poor or incomplete diagnosis accounts for the fact that nearly 80 percent of starters returned as defective on warranty claims work perfectly when tested.

True

When the starter spins but does NOT crank the engine, which of the following may be a cause?

A defectrive starter drive

While the engine is cranked, a voltmeter placed between positive battery post and the positive post of the starter reads less than .01 volt. The cause of this reading could be ______.

Normal resistance in the positive battery cable

A cranking current test is performed, and the amperage is found to be less than specification. Technician A says the starter is bad and it should be replaced. Technician B insists on testing the resistance of the cables, grounds, and connections. Who is correct?

Both A and B

Technician A says the starter solenoid mounts directly on top of the starter motor. Technician B says the starter solenoid pushes the starter drive pinion into mesh with the flywheel teeth. Who is correct?

Both A and B

Checking for excessive resistance in the starting circuit is being discussed. Technician A says connecting a voltmeter across the ground cable from the battery to the ground connection of the cable is the preferred method. Technician B says connecting an ohmmeter across the positive battery cable after it has been removed from the vehicle is the preferred method. Who is correct?

A only

Pinion gear to flywheel ring gear clearance is being discussed. Technician A says if there is too much clearance, there will be a high-pitched noise after the engine starts. Technician B says if there is too little clearance, there will be a high-pitched noise while the starter is cranking the engine. Who is correct?

Both A and B

Technician A says a starter no-load test is conducted with the starter in a bench vise. Technician B says the battery must have a minimum voltage of 9.6 volts during the test. Who is correct?

A only

Technician A says the purpose of the solenoid is to engage the starter pinion into the flywheel's ring gear. Technician B says the solenoid energizes the starter motor by closing the electrical circuit from the battery to the motor. Who is correct?

Both A and B

Technician A says the starter circuit carries high current from the battery to the starter motor. Technician B says the control circuit is a low current circuit that sends current from the ignition switch to the starter relay or solenoid. Who is correct?

Both A and B

Identify five tests used to troubleshoot the starting system.

Battery Load Test

Armature

The rotating part of an electric motor or generator that carries current and produces mechanical motion.

Commutator

A rotary electrical switch in a motor or generator that reverses the direction of current flow in the armature windings.

Compound motors

Electric motors that have both series and shunt field windings to combine the characteristics of both types.

Counter EMF (CEMF)

The electromotive force produced in a motor's armature windings, opposing the applied voltage.

Field coils

Coils or windings in an electric motor or generator that create a magnetic field to interact with the armature.

Flux density

The measure of magnetic field strength, typically in teslas or gauss.

Flux field

The region around a magnet or magnetic material where magnetic forces are exerted.

Neutral safety switch

A safety device in a vehicle that prevents the engine from starting unless the transmission is in the neutral or park position.

Pinion gear

A small gear that engages with a larger gear, often used in starter motors to turn the engine's flywheel.

Reluctance

The opposition of a material to magnetic flux, similar to resistance in electrical circuits.

Series motor

An electric motor where the field winding is connected in series with the armature winding.

Starter frame

The housing or casing that contains the components of an electric starter motor.

Starter relay

An electrical switch used to control the flow of current to the starter motor in a vehicle's starting system.