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109 Cards in this Set
- Front
- Back
Cable Pick |
Length = A + B - C |
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Passive Load |
A load in which the resistance doesn't change if the applied voltage changes. |
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Active Load |
A load in which the power consumed doesn't change if the applied voltage changes. |
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Servicing Chain Motor |
Check Voltage to Coil |
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Device for testing the effectiveness of insulation |
Meg-ohm meter (commonly called a megger) |
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Cold Filament |
Low Resistance Large In-Rush Current |
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Half the Voltage at the same Resistance |
Draws 1/2 the Current |
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Power = |
Voltage2 / Resistance (voltage square divided by resistance) |
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Apprent Power = |
Voltage x Current |
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Dip Switch Settings 1 thru 9 |
1-2-4-8-16-32-64-128-256 |
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Assignment of Dimmers to virtual control channel |
Soft Patch |
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DMX-512 is an ___ bit Protocol |
8-bit |
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DMX- 512 Operates at __________ Kbytes per sec |
DMX@ 250Kbytes Per sec |
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DMX can control _______ dimmers per channel in ________ steps per device |
512 - 256 |
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Maximum Allowable Voltage Drop on Feeders or Branch Circuits |
3% |
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Maximum Total Allowable Voltage Drop on Both Feeder and Branch Circuits |
5% |
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In the case of Capacitive Loads current_______ the Voltage |
Leads |
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In the case of Resistive Loads current is_______with the Voltage |
In phase |
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In an Inductive Load the current ________ the Voltage |
Lags |
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Power Factor = |
cos (phase angle between voltage and current) |
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Power Factor of 1 is a______load |
Resistive |
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Single Phase kVA (formula)
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kVA = (Iphase x Vphase ) 1000 |
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Three Phase kVA (formula) |
kVA = (ILine x VLine x 1.732) 1000 |
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What does an Extension Cord extend? |
It extends the electrical outlet to the power supply cord |
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Power (Watts) = |
V x I |
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Power is |
The rate of doing work |
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What must be on Lock-out Devices |
1 - Identity of employee applying device 2 - the Date the device was applied 3 - a legend that says: "Do Not Energize" |
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An Opto-Splitter can protect a lighting system from_____on the DMX Cable |
Over Voltage |
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A Bull/Company Switch allows an Electrician to |
Disconnect Power from a System |
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At one venue the Chain Motors worked properly with 100' of cable run. At next venue a cable run was 300' and the motors became intermittent. Why? |
Longer cable run caused a Voltage drop |
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On single purchase counter-weight battens, what is the First action an Electrician should take? |
Attach all fixtures before loading counter-weights |
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Best Material for temporarily hanging 15 Luminares on ___? |
schedule 40 iron pipe |
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Best location to ground a portable power generator providing supplementary power to a building for a show? |
at house service entry (where power enters building) or service panel |
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Minimum Voltage allowable on a 120v branch circuit? |
116.4 (3%) |
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For low hanging Fog effect a technician would use ________ |
Dry Ice |
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If two control devices are connected on an Ethernet switch but can't communicate |
The IP address settings are incorrect (should have the same network portion) |
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Live work is only permitted under NFPA 70E (Standard for Electrical Safety in the Workplace) if... |
1- locking out all sources of Energy is Not possible 2- de-energizing a circuit will introduce a greater hazard (e.g., life support system) |
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8 LED fixtures are separatley controlled by a lighting console but currently units #2 & #7 are operating in unison. What's most practical troubleshooting step? |
Verify that the DMX address of each unit is unique. |
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An incoming road board requires 300A of 3-phase , how best to assure for a successful load-in? |
Locate a company switch fed by a transformer capable of delivering the required 300a |
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When a 3phase motor runs incorrectly in reverse rotation you should.. |
Swap two of the phase connections |
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The best method for definitively determining the ampacity of a power panel is |
Check ampacity indicated on Breaker feeding the Company Switch |
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10.0.0.1 is a ______ |
Valid IP address |
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Flame Resistant long Sleeve Shirt, Flame Resistant Pants, and Saftey Glasses |
Personal Equipment required when working on 240v equipment where available fault current is unknown |
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Connection that returns fault current to the source |
Make First Break Last |
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When installation of tails are required at Company panel this is the safest way to proceed |
Lock-out/Tag-out the breaker feeding the panel serving as the Company switch |
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Regarding OSHA/OHSA compliance for the entertainment electrician ______is a concern
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Personel Protection Equipment |
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Most Common service found at a Company switch in North America is? |
120/208v 3-phase |
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On a twist lock connector the __________ connects first when mating |
Ground |
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A Rig of 208V HMI fixtures are on branch circuit breakers from distribution panel. The breakers are within rated use for the current load but are extremly Hot, most likely from? |
Harmonics |
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Best diagnostic tool for working with SCR dimmer system is a ______ |
True RMS Digital Meter |
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DMX "Slot to channel" best describes _______ |
the function of a Soft patch on a console |
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Most Chain motors designed for use in North America operate correctly on___________ voltages |
120/208v |
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The best reason to power up a large Rig in sections is? |
The intial power surge can overload power sources |
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The best way to deal with a non-sinusoidal load is to use a _________ |
Transformer with a High K-rating or an HMT |
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A follow spot puts out 100fc @200 ft with a 40ft beam size. What is the beam size and foot candles at 100' |
20 ft and 400fc 1/2 the size 4x times the intensity |
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When metering the load side of a transformer supplying 120/208v 3-phase what is the minimum category meter to be used? |
Category III |
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To assemble a Cat 5 data cable use a _________ tool |
RJ-45 crimp tool, jacket stripper, cable shears |
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If a lighting designer asks you to "Flag" a light what do you do? |
Wave an hand in front of Luminaire |
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VRMS = |
Vpeak x 0.707 |
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Vpeak = |
V
|
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Phase angle of 0 degrees = |
PF of 1 |
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Phase angle of 90 degrees = |
PF of 0 |
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Loss of power due to resistance is known as |
I2R
|
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Lost power is proportional to the _________ in the circuit |
Resistance |
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Lost power is proportional to the________ of the_________ of the current flowing thru the circuit |
Square of the Current |
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AED UNIT will.... |
not schock if heartbeat is detected |
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MBJ
SBJ |
MainBonding Jumper Secondary Bonding Jumper
|
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Chain Motor is a _________ load |
Linear |
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maximum % of phase current found thru neutral |
173% |
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The average value of a fully rectified sinewave is __________ of peak |
62% |
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Electricity takes________________ to return to source |
as many paths available to it |
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K - Factor |
Rating of how well transformers can handle loads current in the neutral conductor |
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Use a _______ type fire extinguisher on electrical fires. |
Type C extinguisher |
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NEC Code for: - Stage - Carnivals - Motion Picture |
stage - 520 carnivals - 525 Motion Picture - 530 |
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LED's are inherently ___________ loads |
Capacitive |
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Inductive loads have ___________ fields |
electromagnetic |
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Capacitive loads have _____________ fields |
electrostatic |
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An Inductor is to current what a ___________ is to water. |
Paddle wheel |
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RMS voltage = |
.707 of peak |
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Hots can be referred to as |
Ungrounded conducters, phase conductors, live conductors |
|
Neutrals can be referred to as |
The grounded conductor; a normally current-carrying conductor
|
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If fall protection has been used it |
must be taken out of service |
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HRC |
High Rupture Capacity Fuses |
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The rule for Lightning is called the |
30/30 rule (if you hear thunder within 30 seconds of lightning, shut down outdoor generator and wait 30 minutes after last lightning strike to re-start) |
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Maximum units on multi-point bus (daisy chain) |
32 Units |
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Maximum length of ethernet cable is |
100 meters/328 ft. |
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RMD |
Remote device management |
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DMX to Ethernet/ Ethernet to DMX connectors |
Gateway or Protocol converter
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P.O.E. |
Power over ethernet allows 48vdc over 2 - unused wires |
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A isolated ground 120v outlet, used in conjuction with an isolation transformer has a ________ |
Orange triangle on its face
|
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DMX cable must be |
Twisted pair, low capacitance, and 120-ohm characteristic impedance |
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NEC. Rule which allows an over-current device to be located 25 feet after a change in cable size. |
25 foot Tap Rule (sec.520-69) |
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3-phase AC power per leg formula |
KVA / V x 1.732 3 |
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Peak Voltage formula |
Vpeak = Vrms/1.414 |
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RMS Voltage formula |
Vrms = Vpeak x 0.7071 |
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Power Factor formulas |
1- PF = cosine(phase angle) 2- PF = Power(watts)/(V x I ) 3- PF = Real Power(watts) Apparent Power(VA)
|
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Single Phase AC power formula |
P(watts) = V x I x PF |
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What is considered to be the maximum allowable cable length for a DMX Cable?
|
1000 meters or 3281' |
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An Arc Flash Can reach as much as _____________degrees F. |
20,000º |
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Copper expands at what rate when vaporized in an Arc Flash? |
67,000X |
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How much pressure can be created by an Arc Blast? |
Hundreds or possibly Thousands of Pounds per Sq. Ft. |
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Possible sound pressure during an Arc Blast |
160 db or greater |
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At what speed is molten metal, schrapnel, and other material ejected during an Arc Blast? |
Can exceed 700 mph |
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What is the appropriate hard hat to wear near high voltage live work? |
G-Rated, with a non=melting headliner |
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What is the proper footwear when working with high voltage? |
Shoes rated EH for Electrical Hazard |
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What type of dimmer is forward phase? |
SCR/ Triac= Silicone Controlled Rectifier Turns the current on in the middle of the sine wave. Requires choke. Proportional "on" time to "off" time determines dimming. |
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What type of dimmer is reverse phase? |
IGBT= Insulated Gate Bi-Polar Transistor Turns the current off in the middle of the sine wave. Requires no choke. Proportional "off" time to "on" time determines dimming. |
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The most common types of dimming are |
Conventional or Forward Phase (SCR/Triac) Reverse Phase (IGBT) Sinewave Dimming/ High Freq. Sinewave Dimming Pulse Width Modulation
|
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What are the common forms of Lockout/Tagout? |
Simple and Complex |