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HET3 > 302Da > Flashcards

302Da Flashcards

1
Q

Equipment lighting circuits are used to provide illumination. List four (4) purposes
served by these lighting circuits.

A

a) vision during night operation and poor visibility conditions,
b) machine and operator safety,
c) operator convenience and
d) unit appearance.

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2
Q

What is the name of the switch that will prevent the accidental slow discharge of the
battery group when the equipment is parked and not operating?

A

disconnect switch

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3
Q

There are three types of circuit breakers discussed in this module: Type I, Type II and
Type III. Explain why Type II circuit breakers come equipped with a heat-producing
resistor.

A

It holds the circuit breaker in the OFF (open) position while the breaker rating is
exceeded.

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4
Q

From which main electrical circuit does the flood/working lamp circuit receive
electrical power?

A

key switch controlled circuit

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5
Q

The intensity of the instrument-panel lamps can be controlled by the use of:

a) series connected rheostat.
b) pulse width modulated signal.
c) SPST switch.
d) a and b are both correct

A

a and b are both correct.

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6
Q

If the fibre optic instrument-panel illumination system fails, what is the most likely
malfunctioning component?

A

The light source is the most likely malfunctioning component.

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7
Q

The turn signal light circuit has a turn signal flasher connected in its circuit. How is
the turn signal flasher connected in this circuit?

A

series with the turn signal lamp circuit

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8
Q

A unit equipped with LED turn signal and brake lamps must have a solid state
electronic flasher to flash properly. Why does an electromechanical signal light
flasher not flash LED turn signal lamps properly?

A

The LED turn signal lamp does not draw enough electrical current

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9
Q

Entertainment and communication device inference is caused by electromagnetic
energy and is known as

A

inference or static noise.

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10
Q

.___ systems are comprised of two distinct
components: a satellite tracking component (Global Positioning System GPS) and a
communication component (digital satellite up-link).

A

. Equipment tracking systems

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11
Q

Anti-theft systems are unit security systems that can be classed as eithe_____
systems or _____systems, or a
combination of both of these systems

A

alarm systems or theft deterrent systems,

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12
Q

___ are safety devices that are usually installed on the highest point
of the equipment so that the machine can be visible in all directions.

A

Warning beacons

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13
Q

What would result in a circuit when energized, if a technician added two 80 watt
lights hooked in parallel into an existing circuit that had two 55 watt and two 80 watt
lights connected in parallel, and the 24 volt circuit was protected by a 20 amp fuse?

A

The lights would work normally.

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14
Q

How many amps will a 12 volt electric blower motor draw if it is rated at 100 watts?

A

8 amps

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15
Q

Is a disconnect switch wired in series or parallel with the battery group?

A

Series.

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16
Q

Name the two ways a disconnect switch maybe operated.

A

Manually or electrically.

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17
Q

The main circuit protection device is connected in parallel to the machine fuse/circuit breaker box. (T/F)

A

False.

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18
Q

Speedometers can be read directly or indirect. How was the direct reading achieved and how is an indirect reading achieved?

A

A direct reading would be cable driven and an indirect reading would come from an electronic speedometer. That information comes from a speed sensor attached to transmission output shaft

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19
Q

Some charging system warning lamps contain a resistor connected in series with the lamp. T/F

A

False. This resistor is connected in parallel.

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20
Q

What makes an air core gauge?

A

It is wound around a ferrite core rather than an iron core. This makes it small, efficient and inexpensive.

21
Q

What kind of current is given off of a speed sensor?

A

A/C current.

22
Q

Name the 2 voltage pulse generators that are a small permanent magnet style.

A

Rotating permanent magnetic generator and a reluctance voltage generator.

23
Q

What is the purpose of the hour meter?

A

Provides a record of total running time the engine has logged.

24
Q

EEPROM stands for what?

A

Electronically erasable programmable read only memory.

25
Q

What is this EEPROM?

A

It is a non volatile memory in the computer memory that continually updates the electronic hour meter.

26
Q

What precaution should you consider if you change a units rear drive axle ratios or tires?

A

You may need to reprogram or adjust the speedometer accordingly.
Note* this would also correct the odometer accuracy, but, always refer to manufacture specs

27
Q

Where’s the fuel gauge sending unit located?

A

In the fuel tank. It includes a float and a variable resistor.

28
Q

The panel mounted fuel gauge processes the ____________ __________of the fuel sender signal and converts it to a gauge pointer position

A

Resistance value

29
Q

What is one possibility of an inaccurate fuel level reading?

A

Not having a proper electrical ground.

A worn out variable resistor in the sending unit.

30
Q

Temperature gauge

Explain the main quality of an NTC thermistor. (Negative temperature coefficient)

A

Temperature up resistance down

Temperature down resistance up.

31
Q

When changing any sending unit, what must you ensure?

A

Everything must be to manufacture’s specifications.

32
Q

What are five things you can say about a Bourdon tube gauge?

A
  1. it’s a direct gauge
  2. Most accurate between 10 and 2 o’clock
  3. Tube tends to straighten under pressure
  4. May have pressure snubbers
  5. Gauge may be filled with dampening fluid (glycerin)
33
Q

What are two distinct characteristics of a balancing coil pressure gauge and sending unit?

A

It is an analog and indirect pressure gauge.

34
Q

What is a positive quality of a silicone diaphragm pressure sensor?

A

It can be calibrated to any pressure. It just needs to be programmed to ECM required range.

35
Q

What are two possible types of gauges on equipment electrical systems?

A

Ammeter and voltmeter

36
Q

Because an amp meter is always connected in series, what is a major downfall of having that gauge in the cab?

A

A huge cable would be required.

37
Q

A voltmeter is always connected in parallel. What’s the benefit in the cab?

A

Allows a relatively simple inside panel wiring connection

38
Q

What’s the function of an equipment monitoring system?

A

Read the inputs, display alerts, activate an output when necessary.

Possibly display system diagnostic information( codes)

39
Q

True or false

A dimmer switch is used to control the intensity of panel lighting?

A

False - a dimmer MODULE is used

A dimmer switch is used to control high beams (headlights)

40
Q

When a rheostat is used, how are panel lamps dimmed?

A

By lowering the circuits voltage

41
Q

What is duty cycle

A

Percentage of “on” time of a circuit. Expressed as a percentage

42
Q

What are finer optics?

A

Very fine fibres of plastic

43
Q

How much current (amps) do LED lamps take compared to incandescent lamps?

A

Approximately 1/10 of the electrical current that normal incandescent light bulbs require.

44
Q

LED stop lights will provide operators who are behind 10 meters of addition stopping distance, when the equipment is moving at 100 kilometres per hour. T/F

A

True

45
Q

Units equipped with LED turn signal and brake lamps must have what type of flasher to operate properly?

A

A solid state electronic flasher

46
Q

The PM (permanent magnet) motor is not suitable for use in high load applications. T/F

A

False; PM motors can operate loads with high power demands because today’s permanent magnetic technology allows the use of high magnetic strength material.

47
Q

With a PM (permanent magnet) motor, why would we couple the armature to a reduction gearbox?

A

To lower the output speed and raise the torque rating of the PM motor.

48
Q

How do we prevent the accidental, slow discharge of the battery group when the unit is parked and not operating?

A

We use battery-disconnect switches

49
Q

Internal components of equipment tracking are not serviceable the only components we can check are

A

System power supply
Key switch power source
Antenna mounting and its coaxial cables and leads
Data stream link and connections
Mounting of communication link device and its cables

HET3 (34 decks)

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