1. Stage Electrical Tutorial
Brian Lincoln
12/5/18
Strand 300 Series Console with Fader Panels and Processor
Rev 9

2. Purpose of Electrical Tutorial
To explain the basic functions of electrical power needed on a typical stage and describe the terminology
What you will learn…
Fundamental definitions of electricity and circuit
Terminology used in electrical systems
Differences between AC and DC Power forms
Understanding of Voltage, Current, & Power
How a Dimmer Circuit works
Intro to Industry Plug Standards
How to Calculate loads (power) in circuits
4/2/2019

3. Why is Electricity Important to Theater?
Electricity provides the energy to operate all aspects of a modern stage
Electrical power is consumed by ….
Lighting Equipment / Light Board / Fixtures
Audio Gear / Amplifiers / Mics / Mixers
Motor Drives / Winches
Communications / WIFI
Computers / Printers
Stage Props / Foggers / Lamp post / Animatronics
Utility: Chargers / Microwave / Hair Dryers / Fridge
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4. Electrical Energy Provided in 2 Forms
Alternating Current (AC)
Wall Outlet
Dimmer Outlet
Transformer
Generator
Direct Current (DC)
Battery
Power Supply (Converts AC to DC via transformer)
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5. Electricity Performs Work
Electrical Energy is delivered to a load via a circuit
Load is any entity that consumes power to perform useful work, e.g., light bulb, motor, amplifier, drill, table saw, computer
The Electro Motive Force (EMF) or potential source (Voltage) provides electromagnetic pressure to push electrons down a wire (Current)
The combination of voltage and current create “Power” or energy per time
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6. Electrical Circuit – DC Analysis
Switch +
Potential
Source
(EMF)
Load -
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7. Electrical Circuit – Closed Loop
Switch
Current
(Amps) + +
Potential
Source
Voltage
Work
Load - -
Moves Something
Generates Light
Generates Heat
Amplifies Sound
Performs Calc
Transmits RF
Operates Cell Phone
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8. Electrical Circuit – Ohms Law
Switch
I - Current
(Amps) + +
Potential
Source
V – Voltage
(Volts)
Load
R – Resistance
(Ohms) V
Meter - -
Ohms Law
Where:
V = Voltage (Volts)
I = Current (Amps)
R = Resistance (Ohms)
V = I x R
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9. Electrical Circuit - Power
Switch
Work
(Power)
I - Current
(Amps) + +
Potential
Source
V – Voltage
(Volts)
Load
R – Resistance
(Ohms) - -
Ohms Law
Where:
V = Voltage (Volts)
I = Current (Amps)
R = Resistance (Ohms)
Power Law
Where:
P = Power (Watts)
I = Current (Amps)
V = Voltage (Volts)
V = I x R
P = V x I
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10. Electrical Circuit – Parallel Loads
Switch
ITotal I2 I1 + P1 P2 + + +
Potential
Source
V – Voltage
(Volts)
Load 1
Load 2 - - - -
R1– Resistance
(Ohms)
R2 – Resistance
(Ohms)
ITotal = I1 + I2
PTotal = P1 + P2
Loads Can Be Calculated using Current or Power
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11. Electrical Circuit – AC vs DC
Direct Current Circuit (DC)
Alternating Current Circuit (AC)
1st Half Cycle
Switch
Current
(Amps)
Current
(Amps) +
Switch +
FLOW AC
Voltage
Potential
Source
Work
Load
Current
(Amps) + - - +
Potential
Source
FLOW DC
Voltage
Work
Load - -
One Direction
2nd Half Cycle
Switch
Current
(Amps)
Current
(Amps) + +
FLOW AC
Voltage
Potential
Source
Work
Load - -
Reverse Direction
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12. AC vs DC Waveforms DC Power AC Power
Volts
Volts
AMAX = Peak Voltage
ARMS = AMAX x 0.707
AAVG = AMAX x 0.636
12V
+12V
Root Mean Square (ARMS)
Average (AAVG)
Peak
AMAX
Time
Time
Zero
Crossing
-12V
Period (T)
One Cycle
Frequency = 1 / T
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Example: 60 Hz => 16.67ms Period

13. Standard North American AC Power
Edison Power
(RMS)
Typical Wall Outlet (3 pin)
Always on… not dimmed
20 Amp Circuit Breaker
120V x 20Amp = 2400 Watts
Volts
+170V
Root Mean Square (RMS)
+120V
Peak
Time
-170V
Period (T)
16.667ms
60 Hz
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14. Where Does Edison Power Come From?
Neutral
Hot
Ground
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Service Panel
Outlet

15. Circuit Breaker Protects Over Current Draw
Circuit Breaker is designed to open the circuit loop if the current draw exceeds the rating of the breaker
Provides Protection…Watchdog
Without a Breaker, drawing too much current can over heat the wires and cause a fire
Circuit Breaker is triggered internally via thermal mechanism; High current results in temperature increase, tripping the breaker
If over current draw trips breaker,
it can be reset by flipping
switch off, then on again
4/2/2019

16. Dimmer Circuit Power Forms
Strand Dimmer Outlet
20Amps (2400 Watts) with 0 to 100% dimming capability typically for light fixtures
Found on the Electric Bars and various ground level stations around the stage walls
Use 3 pin Twist Connector (typically) but can also accommodate an Edison Nema 5-20 or 5-15; 3 pin plug
Do not run motors (inductive loads) on the dimming circuits; Only run Resistive loads such as incandescent bulbs
Dimmer packs located in the attic in Stack
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17. Basic Lighting System Block Diagram
Light Board Controller In
Tech Booth
DMX Bus
Dimmer Stack In
Attic
Dimmer
Dimmer
Dimmer
Dimmer
Dimmer
Dimmer
Back Stage or
on Electricals
Near Lights
Dimmer 1
Outlet
Dimmer 2
Outlet
Dimmer 3
Outlet
Dimmer 180
Outlet
120 VAC
120 VAC
120 VAC
On Gaffers,
Battens and
Electricals
(above stage)
Light 1
Light 2
Light 3
Light 4
Light 5
Light 6
Light 7
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18. How Does A Dimmer Work?
Dimmer Stack (In Attic)
DMX Bus
(Address and Data)
120 VAC
Power Source
Micro
Controller
Triac
Dimmer #123
Micro
Controller
Triac
Dimmer #124
Micro
Controller
Triac
Dimmer #125
Micro
Controller
Triac
Dimmer #126
DimmerOutlet
DimmerOutlet
DimmerOutlet
DimmerOutlet
Light
Bulb
Light
Bulb
Light
Bulb
Light
Bulb
Dimmer Units receive signal from Light Console through DMX Bus
Convert small signal to high current output to light fixture
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19. Dimmer Circuit – Pulse Width Modulation (PWM)
Volts
Volts
Volts
Time
Time
Time
0% (Off)
25%
50%
Area Under Curve
is “On Time”
Volts
Volts
Time
Time
90%
100% (Full On)
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20. Strand Dimmer Rack – Stage 192 Dimmer System
Dimmer Pack
Inserted in Rack
2 Control Computers
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Dimmer / Control Rack
2.4 kW Dual Dimmer Pack

21. 180 Dimmer Outlets – Located Around Stage
Dimmer Address and relative location on Electrical Bar
The 4 “Electrics” above Stage
The 2 Catwalk “Electrics”
In front of Stage
At Ground level
On Wall
In Ceiling
On Batten
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Dimmer Outlet Boxes
Dimmer Outlet Boxes (Above)

22. Typical DC Power Forms On Stage
12 VDC Wall 3 Amps (Transformer)
24 VDC Wall 5 Amps (Transformer)
USB 2 Amps (Transformer or Regulator)
Batteries
AAA 3 Amps
AA 3 Amps
500mA
12VDC Lead 300 Amps
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23. Power Plugs NEMA 5-20 or 5-15 for Edison Power
NEMA L5-20 Twist for Dimmer Power
Stage Pin Plugs (Not used at IRHS)
PowerCON for Edison Power
COAX 2.1mm for 12VDC and 5VDC Wall Warts
COAX 2.5mm for higher current draws
USB for 5VDC
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24. NEMA Plug /Outlet Edison Power Circuit For Stage Edison Power Circuit
For Home and Stage
Dimmer Power Circuit
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25. Typical Plugs Used on Stage
NEMA 5-15
NEMA 5-20
NEMA L5-20
Edison
Stage Pin
IEC
PowerCON
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Stage Pin

26. Typical DC Plugs & Transformers
2.1mm & 2.5mm Coax
6VDC Wall Wart 2.1mm Coax
12VDC Power Suppluy 2.5mm Coax
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USB 5VDC

27. Calculating Loads
Add up number of loads on a circuit using current or power rating and assess if greater than circuit breaker rating
Try not to load circuits to full capacity… leave margin of 25% to 50%
Example 1:
Qty 3 of the 575W Ellipsoids on a 2400W dimmer outlet circuit…
3 x 575W = 1725W which is less than 2400W (72% loaded) …OK!
Example 2:
Qty 2 foggers (12 Amps each) on a 20 Amp Edison outlet circuit…
2 X 12 Amps = 24 Amps which is greater than 20 Amp (120% loaded)…NOT OK!!
4/2/2019

28. Stage Light Fixture Examples
PAR
Cyc
Ellipsoidal
300W
500W
575W to 1000W
Slide Projectors
Scoop Flood
200W
Fresnel
200W
500W
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29. Motion Lights Fixtures
MAC 250
13 Channels
Q Spot 200
10 to 14 Channels
325W
334W
RUSH
16 Channels
Intimidator (Scanner)
5 Channels
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300W
165W

30. LED Intelligent Fixtures
100W
40W
50W
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50W
30W

31. Lumens and Watts Conversion Charts
Lumens for Light Source Watts
Lumens
Incandescent Watts
LED Watts
375 25 6
450 40 10
800 60 15
1100 75 19
1600
100
2600
150 38
3000
200 50
14,000
575
233
21,900
750
365
Luminous Efficacy
Light Source
Luminous Efficacy (Lumens/Watt)
Incandescent
12-18
Halogen
16-24
LED
30-90
Efficiency of Light Source
(How well it converts electrical power into light power)
Higher ratio is better
Light Output
(Luminous Power)
Electrical Power
Consumed
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32. Summary Electricity provides energy to perform work on a stage
Comes in Alternating Current (AC) or Direct Current (DC) forms
An electrical circuit must be closed to deliver power to load
120VAC power - Edison is always on whereas a Dimmer circuit is adjustable from 0 to 100%
Ohms Law and Power Law govern electrical behavior
Power plugs are sized and rated per their current capability; Come in various sizes and shapes
Circuit Breakers provide overload protection
Parallel Loads can be assessed by adding up current or power and compared to circuit breaker rating
LED Lights provide more Lumens than Incandescents with less power consumption
Understanding the concepts of electricity make you a smarter and safer stage tech
4/2/2019