Electrical Repair Flashcards
How fast, approximately, does a SI engine need to spin to start?
40-60rpm.
How fast, approximately, does a CI engine need to spin to start?
80-100rpm
What are the major components of the starting system?
Battery, ignition switch, starter relay, starter motor, and ring gear.
What are the common types of ignition switch systems?
Key start, remote starting, push button, stop/start, or hybrid
How does a key start system work?
When the key is turned, it sends voltage to terminal 30 on the starter, which allows the battery to send voltage to terminal 50, which causes the starter to turn.
How does remote starting work?
The remote starting system is similar to the basic system, although it has an ECU, and when the engine speed rises above cranking speed, the ECU cuts the voltage to the starter relay.
How does push button start work?
The push button start system usually utilises the remote starting system, although it uses a button instead of a key.
What happens if a conductor is placed between the N and S poles of a permanent magnet?
The lines of magnetic force from the conductor and magnet interfere, causing the magnetic flux to increase at the bottom of the conductor and decrease at the top.
How is strength of EMF (electromagnetic force) calculated?
F = B (density of flux) * I * t (length of conductor)
What does the commutator do in a motor?
It swaps the polarity of the conductor so that it will continue to rotate in the correct direction as it passes the top or bottom of a cycle.
How does a series wound DC motor work?
The field coil and armature coil are connected in series. Current flows through the armature coil and field coil in a single series circuit.
How does a shunt wound DC motor work?
The field coil and armature coil are connected in parallel. Current flows through the armature coil and field coil via separate parallel circuits.
How does a compound DC motor work?
This motor uses a combination of series and parallel circuits to connect the field coil and armature coil.
What beneficial characteristic does a series wound DC motor have for a starter motor?
It draws high current and develops large torque at low speed.
What are the characteristics of a reduction starter motor?
It uses a motor which puts out less torque than a conventional motor, although it achieves the same torque by using gear reduction. The plunger of the magnetic switch acts directly on the pinion as it’s on the same axis.
What are the characteristics of a conventional type starter motor?
The armature and pinion gear are on the same axis and spin at the same speed. A drive lever attached to the magnetic switch plunger pushes the pinion.
What are the characteristics of a planetary type starter motor?
It is similar to the conventional type, although it uses a planetary gear set to increase drive torque so that a smaller armature can be used.
What are the characteristics of a planetary reduction segment conductor type starter motor?
This starter motor is very similar to the planetary type, although uses permanent magnets instead of field coils.
What are the major components of a starter motor?
Magnetic switch, armature, yoke sub-assembly, brush and brush holder, overrunning clutch, and pinion gear and helical spline.
What does the magnetic switch in a starter motor do?
It operates engagement of the pinion gear and controls the flow of electricity through the motor, it works the same as a solenoid.