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Electrical (Period 1 Electrician) > Systems, Mod 7 and 8 > Flashcards

Systems, Mod 7 and 8 Flashcards

1
Q

what reading should an ohmmeter get when measuring a NO pushbutton pressed down?

A

0 ohms

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2
Q

what does an extra low voltage switching system relay use?

A

extra low voltage circuit to control low voltage circuit

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3
Q

can an extra low voltage switching system control 120 v loads?

A

yes provided that the switches have 24v

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4
Q

why is an extra low voltage system safer than a line voltage?

A

protective isolation barrier from line voltage

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5
Q

what colour is the wire going to the pilot light?

A

yellow

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6
Q

What colour wires do the following need:

L1-
L2-
X1-
X2-
ON relay-
OFF relay-
Diode wire-

A

Black
White
White
Blue
Red
Black
White and Blue

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7
Q

Momentary contacts in switches are in the neutral position until pressed on or off.

True or False

A

True

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8
Q

In a three wire extra low voltage switching system relay the power contacts close when the on coil becomes energized. When the on coil is then de-energize the power contacts are:

A

Closed because they are mechanically held

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9
Q

In an extra low voltage switching system are the switches controlling the relay permanent?

A

No, they’re momentary.

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10
Q

What are the voltages permitted to be called “extra-low voltage”?

A

AC- not exceeding 30V
DC- not exceeding 42.4V

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11
Q

What are some advantages of using extra-low voltage?

A
  1. only need to be rated for extra low voltage (equipment)
  2. Requires small guage wires so less material
  3. fewer power loss
  4. cheaper
  5. can operate a single relay
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12
Q

can one extra low voltage switch control several relays?

A

yes

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13
Q

when energized what are the positions of the latch, and the contacts?

A

latch is closed, holding in place, and contacts are closed.

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14
Q

when de-energized what are the positions of the latch, and the contacts?

A

latch is open (OFF position), and contacts are open.

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15
Q

What is a rectifying diode?

A

A diode pulses the current going through it only in the direction indicated on the diode changing current from AC to DC. SO as to not burn out the relays.

NOT RATED FOR CONTINUOUS OPERATION

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16
Q

what is the purpose of an LED pilot light

A

to indicate if a light is on or off either from the room with the lights or from a separate isolated room.

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17
Q

what is the ON sequence for a 2 wire relay?

A
  1. on diode engaged, light off, switch not pressed

2.switch pressed on, coil energized, contacts close, light turns on

  1. off diode engaged when contacts close
  2. switch not pressed, off diode engaged.
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18
Q

what is a PoE?

A

Power over Ethernet

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18
Q

what is the OFF sequence for 2 wire relay?

A
  1. switch not pressed, contacts closed, off diode engaged
  2. switch pressed off, coil energizes, contacts open
  3. ON diode engaged after contacts open
  4. switch not pressed, ON diode engaged, contacts open, light off.
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19
Q

What is IP?

A

Internet Protocol

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20
Q

What is VoIP?

A

Voice over Internet Protocol

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21
Q

What is PSE?

A

Power Sourcing Equipment

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22
Q

What is PD?

A

Powered Device

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23
Q

what is one example of a common system that uses PoE?

A

wireless routers
VoIP phones
IP
security cameras

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24
3 basic components of a PoE:
PSE Ethernet cabling PD
25
4 standard output power ratings of PSE:
type 1- 15.4W type 2- 25.5W type 3- 55W type 4-100W
26
when are Endspans used?
when building PoE systems, from scratch
27
When are Midspans used?
when adding to existing PoE that does not support PoE
28
Earlier models of motion detectors were developed with principals similar to:
radar
29
what are Magnetic reed switches used for?
perimeter device contact on doors and windows
30
How can each area of protection zone of an alarm be programmed?
each zone can be programmed differently
31
what does a MICROWAVE motion detector measure?
movement
32
where does a CPU receive its power?
AC supply
33
What code states that smoke alarms must be installed in residential units?
Alberta Building Code
34
Smoke alarms shall be wired, independently or interconnected?
interconnected
35
when a short circuit occurs what is the response of a Class B DETECTION circuit?
Alarm
36
when a short circuit occurs what is the response of a Class B SIGNAL circuit?
Trouble
37
what is an EOL?
End of Line
38
what happens in a NO system loop if there is a point of contact?
alarm goes off when contacts close
39
what happens in a NC system loop?
alarm goes off when contacts open
40
what happens in a monitored system loop?
EOL resistors monitor circuit
41
what are the OUTPUT devices of a fire alarm circuit?
siren and strobe light
42
is it acceptable to install sirens next to cold air ducts?
yes, it echoes sound.
43
are recessed contacts used for windows?
no, doors.
44
what would be the best perimeter device for a sealed window?
surface mount contact with magnetic reed switch.
45
can overhead doors have a recessed contact?
no, must have large overhead magnetic contact.
46
True or false: T- mounting position is used and is permitted in installations.
false
47
where is an acoustic shock detector typically installed? what does it detect?
ON the glass pane, senses air pressure change when glass is broken.
48
Acoustic sound pattern detectors detect what?
They are pre-programmed with the actual sound pattern of glass breaking and go off at that sound
50
What do passive infrared detectors or PIRs detect?
They are sensitive to moving heat radiating sources such as people and animals
51
True or false When using PIR technology you need to make sure it covers different areas based on angle and pattern
True
52
When using wireless devices where must you ensure that it is installed?
You must ensure that a large metal device such as a chimney or duct is not located between the transmitter module and the wireless receiver
53
What is another name for an ionization detector?
Product of combustion detector
54
What is the function of a smoke detector
To detect smoke
55
Photoelectric smoke detectors detect what?
They are light obstruction style detectors. Shining a light beam across a sensing chamber determining how much of it is penetrating from the light source to the receiver. If below a certain value the alarm will sound.
56
What section of the Canadian electrical code book provides a summary on the installation of smoke alarms?
32-200
57
When wiring a smoke detector what are the colors corresponding with power and interconnection?
White is the identified conductor Black is live power Either orange red or yellow are used as interconnection between smoke alarms.
58
What are fixed temperature detectors?
They will detect the presence of fire when a heat sensitive material inside the detector melts Commonly set around 57°c or 93° c
59
In the conditions of a fire alarm system when it stated to be in normal condition what is the property?
Ready to receive input signals
60
In a fire alarm circuit when the condition States trouble what does that mean?
There was an equipment failure or circuit failure indicated on the control panel
61
In a fire detection and alarm system when the condition states to be an alarm mode what is the property?
When a detection device or manual pull station is activated
62
In a fire detection and alarm system under the conditions of a fire alarm system when stated to be in supervisory what is the property?
A change in condition of a field device
63
When conventional field devices are connected in a common circuit the control unit cannot identify an individual field device these devices are____________.
Non-adressable
64
When an initiating circuit or smoke detector activates what happens to the supervisory current?
Increases
65
With assistant change in a signal circuit such as a short circuit what happens to the supervisory current?
Increases
66
What does a carbon monoxide detector detect and what causes it to go off?
Detects carbon monoxide which is a colorless odorless and tasteless gas produced by incomplete combustion of fuels such as wood coal gas and oil

Electrical (Period 1 Electrician) (13 decks)

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