Electrical Apparatus & Circuits Flashcards
Low Voltage (LV)
Between 50V & 1000V AC or 120V to 1500V DC (License Required)
High Voltage (HV)
More than 1000V AC or 1500V DC (License Required)
Extra Low Voltage (ELV)
Below 50V AC or 120V DC (No License Required)
MEN
Multiple Earthed Neutral
Three-Phase Colour Coding (New)
L1 (Brown, L2 (White), L3 (Grey), N (Blue), E (Green/Yellow). The phases are 120 Deg. apart
Three-Phase Colour Coding (New, Equipment)
L1 (Brown, L2 (White), L3 (Grey), N (Blue), E (Green/Yellow). The phases are 120 Deg. apart
Three-Phase Colour Coding (Old)
L1 (Red), L2 (White), L3 (Blue), N (Black), E (Green)
Leading Edge
In a Square or Sawtooth Wave; the ascending edge of the wave.
Trailing Edge
In a Square or Sawtooth Wave; the descending edge of the wave.
Three-Phase Colour Coding (New, Installation)
L1 (Red), L2 (White), L3 (Blue), N (Black), E (Green/Yellow)
Three-Phase Colour Coding (New, Installation)
L1 (Red), L2 (White), L3 (Blue), N (Black), E (Green/Yellow)
PEN
Protective Earth Neutral
Star Point
The terminals of the three branches are connected to a common point. The network formed is known as Star Connection
Delta Point
The three branches of the network are connected in such a way that it forms a closed loop known as Delta Connection
EPR
Earth Potential Rise
In a sine wave, RMS Voltage equals…
…Peak Voltage x Square Root of 2
Step Potential
An electrified grounded object radiates electricity in rings. Stepping across these rings can cause current to flow through your body.
In a sine wave, RMS Voltage equals…
…Peak Voltage x Square Root of 2
Australian Wiring Standard
Wiring Rules AU/NZS 3000
Touch Potential
Touching an electrified object has the potential to allow electricity to flow through your body to the ground.
RCD, RCCB, ELCB
Residual Current Device / Residual-Current Circuit Breaker / Earth-leakage Circuit Breaker. Can be single or three phase.
Toroidal Coil
…
MCB
Miniature Circuit Breaker
Tong Tester / Clamp Meter
…
Type 1 RCD
10mA - Medical
Type 2 RCD
30mA - Domestic
Type 3 RCD
100mA
Type 4 RCD
100mA
GPO
General Power Outlet
Earth Pit
…
Earth Stud / Bar
…
Primary and Secondary Transformer
…
Earth Potential Rise (EPR)
…
Equipotential
(of a surface or line) Composed of points all at the same potential.
Installation Categories
Category I: Electronic circuits
Category II: Portable appliances
Category III: All distribution circuits, mains, air-conditioners, hot water heaters, ranges
Category IV: Consumer mains, power consumption meters,
Ingress Protection (IP)
…
HRC Fuse
High Rupturing Capacity Fuse
gG (gL), gM Fuses
…
Motors are rated in two units:
Horsepower (HP) or Kilowatt (kW)
NEMA, IEC
National Electrical Manufacturers Association, International Electrotechnical Commission
Burden of Coil
…
Inverse Time Graph
…
Hysteresis
The phenomenon in which the value of a physical property lags behind changes in the effect causing it, as for instance when magnetic induction lags behind the magnetizing force.
Hysteresis
The phenomenon in which the value of a physical property lags behind changes in the effect causing it, as for instance when magnetic induction lags behind the magnetizing force.
NO / NC
Normally Open, Normally Closed
Enamel
An opaque or semi-transparent glossy substance that is a type of glass, applied by vitrification to metallic or other hard surfaces for ornament or as a protective coating.
PCB
Printed Circuit Boards
Interlocking, Cross-Interlocking
…
Cowl
A protective covering for a circuit or apparatus.
Contactor
A contactor is an electrically-controlled switch used for switching an electrical power circuit.
CE (manufacturing symbol)
The CE mark indicates that the product may be sold freely in any part the European Economic Area, irrespective of its country of origin.
SPDT
Single Pole Double Throw, a switch that only has a single input and can connect to and switch between 2 outputs.
Switchgear
…
Gland
A sort-of sleeve, either metal or PVC, which holds the insulation of a cable and keeps it steady within a device.
Gland Plate
The plate on which a gland is attached
Lug
A type of connector - the cable is crimped into the open end of the lug, the other end is designed to be bolted
Neutral and Earth Bars
…
Earth Stake or Rod
…
Looping
The continuation of a control circuit by looping from one input to the next. It’s bad practice to put more than two cables per terminal.