ETCP Electrical Exam
RMS voltage =
.707 of peak
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"
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)
Dip Switch Settings 1 thru 9
1-2-4-8-16-32-64-128-256
Power =
1. [VxI] 2. [RxIsquared] 3. [V2/R]
Power Factor formulas
1. cosine[phase angle] 2. Power[watts]/[VxI] 3. Real Power[watts]/Apparent Power[VA]
Maximum length of ethernet cable is
100 meters/328 ft.
What is considered to be the maximum allowable cable length for a DMX Cable?
1000 meters (3281')
Minimum Voltage allowable on a 120v branch circuit?
116.4 (3%)
Most Chain motors designed for use in North America operate correctly on___________ voltages
120/208v
Most Common service found at a Company switch in North America is?
120/208v 3-phase
maximum % of phase current found thru neutral
173%
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)
An Arc Flash Can reach as much as _____________degrees F.
20,000º
NEC. Rule allowing an over-current device to be located 25 feet after a change in cable size.
25 foot Tap Rule (sec.520-69)
Maximum Allowable Voltage Drop on Feeders or Branch Circuits
3%
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)
Maximum units on multi-point bus (daisy chain)
32 Units
Maximum Total Allowable Voltage Drop non Both Feeder and Branch Circuits
5%
DMX can control _______ dimmers per universe in ________ steps per device
512 - 256
The average value of a fully rectified sinewave is __________ of peak
62%
Copper expands at what rate when vaporized in an Arc Flash?
67,000X
DMX-512 is an ___ bit Protocol
8-bit
Active Load
A load in which the power consumed doesn't change if the applied voltage changes.
Passive Load
A load in which the resistance doesn't change if the applied voltage changes.
Soft Patch
Assignment of Dimmers to virtual control channel
On single purchase counter-weight battens, what is the First action an Electrician should take?
Attach all fixtures before loading counter-weights
LED's are inherently___________ loads
Capacitive
When metering the load side of a transformer supplying 120/208v 3-phase, what is the minimum category meter to be used?
Category III
Servicing Chain Motor
Check Voltage to Coil
The best method for definitively determining the ampacity of a power panel is...
Check ampacity indicated on Breaker feeding the Company Switch
DMX- 512 Operates at __________ Kbytes per sec
DMX@ 250Kbytes Per sec
Meg-ohm meter (commonly called a megger)
Device for testing the effectiveness of insulation
A Bull/Company Switch allows an Electrician to
Disconnect Power from a System
Half the Voltage at the same Resistance
Draws 1/2 the Current
For low hanging Fog effect a technician would use________
Dry Ice
Personal Equipment required when working on 240v equipment where available fault current is unknown
Flame Resistant long Sleeve Shirt, Flame Resistant Pants, and Safety Glasses
DMX to Ethernet/Ethernet to DMX connectors
Gateway or Protocol converter
On a twist lock connector the __________ connects first when mating
Ground
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 extremely hot, most likely from?
Harmonics
HRC
High Rupture Capacity Fuses
In the case of Resistive Loads current is_______with the Voltage
In phase
What does an Extension Cord extend?
It extends the electrical outlet to the power supply cord
In an Inductive Load the current ________ the Voltage
Lags
In the case of Capacitive Loads current_______ the Voltage
Leads
Cable Pick
Length = A + B - C
Chain Motor is a _________ load
Linear
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
When installation of tails are required at Company panel, the safest way to proceed is...
Lock-out/Tag-out the breaker feeding the panel serving as the Company switch
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
Cold Filament
Low Resistance\Large In-Rush Current
MBJ\SBJ
Main Bonding Jumper\ Secondary Bonding Jumper
Connection that returns fault current to the source
Make First\Break Last
A isolated ground 120v outlet, used in conjunction with an isolation transformer has an
Orange triangle on its face
An Opto-Splitter can protect a lighting system from_____on the DMX Cable
Over Voltage
Single Phase AC power formula
P(watts) = V x I x PF
Phase angle of 90 degrees =
PF of 0
Phase angle of 0 degrees =
PF of 1
An Inductor is to current what a___________ is to water.
Paddle wheel
Regarding OSHA/OHSA compliance for the entertainment electrician______is a concern
Personel Protection Equipment
P.O.E.
Power over Ethernet allows 48vdc over 2 unused wires
To assemble a Cat 5 data cable, use a _________ tool
RJ-45 crimp tool, jacket stripper, cable shears
K - Factor
Rating of how well transformers can handle loads current in the neutral conductor
RMD
Remote device management
Lost power is proportional to the _________ in the circuit
Resistance
Power Factor of 1 is a______load
Resistive
Lost power is proportional to the________ of the_________ flowing thru the circuit
Square of the Current
When a 3phase motor runs incorrectly in reverse rotation you should...
Swap two of the phase connections
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)
Neutrals can be referred to as
The grounded conductor; a normally current-carrying conductor
The best reason to power up a large Rig in sections is?
The initial power surge can overload power sources
Power is
The rate of doing work
The best way to deal with a non-sinusoidal load is to use a _________
Transformer with a High K-rating or an HMT
Best diagnostic tool for working with SCR dimmer system is a ______
True RMS Digital Meter
DMX cable must be
Twisted pair, low capacitance, and 120-ohm characteristic impedance
Use a _______ type fire extinguisher on electrical fires.
Type C extinguisher
Hots can be referred to as
Ungrounded conductors, phase conductors, live conductors
Vpeak =
V
Power (Watts) =
V x I
10.0.0.1 is a ______
Valid IP address
8 LED fixtures are separately 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.
Apprent Power =
Voltage x Current
Peak Voltage formula
Vpeak = Vrms/1.414
VRMS =
Vpeak x 0.707
RMS Voltage formula
Vrms = Vpeak x 0.7071
If a lighting designer asks you to "Flag" a light what do you do?
Wave a hand in front of Luminaire
Loss of power due to resistance is known as
[I squared]R (copper loss/winding loss)
3-phase AC power per leg formula
[KVA / V x 1.732]/3
Electricity takes________________to return to source
as many paths available to it
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
Power Factor =
cos (phase angle between voltage and current)
Inductive loads have___________ fields
electromagnetic
Capacitive loads have_____________ fields
electrostatic
Three Phase kVA (formula)
kVA = (ILine x VLine x 1.732)/1000
Single Phase kVA (formula)
kVA = [Iphase x Vphase]/1000
AED UNIT will....
not shock if heartbeat is detected
Best Material for temporarily hanging 15 Luminares on ___?
schedule 40 iron pipe
NEC Code for: - Stage - Carnivals - Motion Picture
stage 520, carnivals 525, motion Picture 530
If fall protection has been used it must be
taken out of service
DMX "Slot to channel" best describes _______
the function of a Soft patch on a console
