Electrical Fundamentals - A

Question 1

Type 1 circuit breakers

Answer 1

Cycle off (open) when rating is exceeded, automatically reset when over load is removed from the system.
Are a cycling breaker

Question 2

Type 2 circuit breakers

Answer 2

Come with a heat-producing resistor and bi-metallic strip. The resistor heats up when exposed to high current and pushes the strip away opening circuit.
Are a non-cycling breaker

Question 3

Type 3 circuit breakers

Answer 3

Are push button manual reset

Question 4

Fusible link

Answer 4

Stretch of wire 4 awg smaller then the wire in the circuit where it is placed

Question 5

Headlights must have what power source and breaker?

Answer 5

Low beams must be connected to the constant power terminal. Both high and low beam systems must use type 1 breakers

Question 6

The daytime running light module sends what voltages out to the lights.

Answer 6

2-3 volts less then normal (9-10 at light)

Question 7

Night running lights must be connected into what circuit?

Answer 7

Can only run when high beams are on

Question 8

Clearance lights

Answer 8

Indicate the outer dimensions

Connected to constant power terminal

Question 9

Marker Lights

Answer 9

Indicate the upper regions

Connected to constant power terminal

Question 10

Tail Lights

Answer 10

Indicate the rear dimensions, must be red

Connected to the constant power terminal

Question 11

Switch poles and throws

Answer 11

Poles - the number of power terminals in

Throws - the number of output options

Question 12

Pulse width modulation

Answer 12

Signal is turned on and off to control the intensity

Question 13

Turn signal flasher

Answer 13

Either a electromechanical device or a solid state electronic device. The electromechanical flasher will not typically work with the low current draw of LED’s

Question 14

Solenoids

Answer 14

A electromagnetic device that changes electrical energy into linear energy

Question 15

What are the 3 categories of solenoids?

Answer 15

Discrete
Proportional
Latching

Question 16

Discrete Solenoids

Answer 16

A return spring holds the plunger in the relaxed position. Has 2 positions: fully retracted or fully extended

Question 17

Proportional Solenoid

Answer 17

Provides an infinite number of plunger positions. Movement directly proportional to the voltage applied. Plunger works against a spring. Coil is designed to operate continuously; windings are made of many turns of fine-diameter copper conductors

Question 18

Latching solenoid

Answer 18

Is a discrete solenoid that remains fixed at the end of its travel when the coil is de-energized. Not internally grounded and are controlled by a current-reversing circuit.

Question 19

Self-induction

Answer 19

The process of producing a voltage in the coil circuit when current flow stops. Caused by the collapse of the magnetic field

Question 20

What are the 2 way to prevent switch arcing from self-induction

Answer 20

Install a high value resistor in parallel with the solenoid coil.
Clamping diode is installed

Question 21

Clamping diode

Answer 21

Self-discharge diode. Acts as a one way check valve, the solenoid coil can be energized normally, but when it produces a self-induced voltage, the current is not allowed to flow and the self-induced voltage will not rise

Question 22

DC motors use what to create motion?

Answer 22

Electricity and magnetism

Question 23

Counter electromotive force (CEMF)

Answer 23

The voltage produced by a operating dc motor. Is increased as the speed of the motor is increased, this allows less EMF to flow through. This balance is what governs the speed of the motor

Question 24

Slow dc motor speed

Answer 24

Generates high levels of torque. The low levels of CEMF mean that high EMF current which generates high levels of heat

Question 25

What prevents a dc motors generating effect from transmitting voltage

Answer 25

Blocking diode

Question 26

Permanent magnet DC motors

Answer 26

Uses strong magnets to create stationary magnetic field. CEMF is the only factor that limits the motors speed. Used for high-load applications as they are low maintenance, reliable and provide constant torque

Question 27

Permanent magnet motors are reversed how?

Answer 27

Changing the polarity of the input of the motor. ILM does this with a double pole double throw switch

Question 28

Field wound dc motors

Answer 28

Field coils wrap around the pole shoes, which are wound in opposite directions. This creates a magnetic field in the housing

Question 29

Parallel wound dc motor

Answer 29

Also called shunt motor. Field coils and armature are wound in parallel. This allows the field coils to maintain a even mag. field strength as the speed of the armature fluctuates. It also prevents CEMF from flowing through field

Question 30

Field wound motor reversal

Answer 30

Requires connection changes inside of the motor. Must add extra switches and make internal motor wiring connections to change the current flow in either armature of field.

Question 31

What are the 3 ways to control speed in a electric motor

Answer 31

Variable electrical resistance Multiple shunt windings Pulse width modulation

Question 32

Variable resistance speed control

Answer 32

A resistor reduces the amount of voltage that is delivered to the motor. have a thermal fuse a current protection

Question 33

Multiple Shunt windings

Answer 33

1 set of coils are small, 1 set of coils are large. Slow uses small coils, med. use large coils, high uses both coils to generate field strength

Question 34

Pulse width modulation

Answer 34

Solid state module connected in series turns electrical current on and off. amount of time on (%) is the duty cycle. the longer the on time the faster the motor spins

Question 35

What are the 3 ways to dis-engage the cruise control on a truck.

Answer 35

Step on brake pedal Step on clutch/ auto trans. into neutral Dash switch

Question 36

Battery isolation switches

Answer 36

Disconnect main ground just before batteries

Question 37

When by-passing the battery isolation switch what must be installed?

Answer 37

Fuses on both the positive and negative leads

Question 38

What can you install to reduce or eliminate interference and static noise?

Answer 38

A series coil (filter choke) or a parallel-connected capacitor the the units power lead

Question 39

If an entertainment or communication device requires a cable to transmit processed info, it must have?

Answer 39

A proper shield on the cable

Question 40

What are the 3 most common truck position sensing systems?

Answer 40

Collision warning system (CWS) Adaptive Cruise Control (ACC) Collision mitigating system (CMS)

Question 41

What sensor does a collision avoidance system use to detect that the vehicle is traveling around a curve?

Answer 41

Gyro sensor

Question 42

Park contacts

Answer 42

A set of switch contacts located inside the motor, they supply power to motor after switch has been turned off until motor returns to park position.