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Night Lighting: Part 4
Continued from above.
To maximize the number of lights that you can run off your portable generator, I would suggest you run all your HMIs on Power Factor Corrected ballasts. This will not be easy because until recently Power Factor Correction (PFC) has not been readily available in 800 or 1200 Watt HMI ballasts in this country (the EU countries are further along in this respect), and not always available in 2500 and 4000 Watt ballasts. A name brand to ask for is Power-2-Light. Power-2-Light is the only ballast manufacturer to include Power Factor Correction (PFC) as standard in their 800w, 1200w, 2.5kw/4kw electronic ballasts. Formerly only available in the larger ballasts of other manufacturers, this advanced electronics reduces current spikes and harmonics in the power line and contributes to a more economical use of power than typical electronic ballasts. For this reason, Power-2-Light PFC electronic ballasts enable the operation of both larger HMIs, or more smaller HMIs, off of standard wall outlets and portable generators. Power-2-Light PFC ballasts, used in conjunction with our modified Honda EU6500is generator and a step-down transformer/distro, can go a long ways towards eliminating the need for large diesel generators, or dangerous tie-ins, in many situations.
Until the introduction of PFC circuitry in smaller HMI ballasts it was not possible to reliably operate more than a couple 1200W HMIs with non-PFC ballasts on a conventional generator because of the voltage waveform distortion they created. The harmonic noise that magnetic and non-PFC electronic ballasts kick back into the power stream has an adverse effect on the power waveform of conventional generators where it does not on grid power. Normally, when you plug an HMI light into a wall outlet you need not be concerned about current harmonic distortion producing voltage distortions. The impedance of the electrical path from the power plant is so low, the distortion of the original voltage waveform so small (1-3%), and the plant capacity so large, that inherently noisy loads placed upon it will not affect the voltage at the load bus.
However, it is an all together different situation when plugging HMIs and Kinos into conventional portable generators. Given the large sub-transient impedance of conventional portable generators, even a small degree of harmonic noise being fed back into the power stream will result in a distortion of its’ voltage. Add to that, the likely hood that the percentage of the generator’s capacity taken up by non-linear loads (HMI or Kino ballasts) will to be very high given its small size relative to typical lighting loads, and given the increasing prevalence of non-linear light sources (HMI & Kinos) in production. Finally, add that the original supply voltage waveform of a conventional generator is appreciably distorted to begin with, and you have a situation where the return of any harmonic currents by an HMI or Kino ballast will result in significant waveform distortion of the voltage in the distribution system.
In the past, the primary factors limiting the use of HMIs on portable generators has been their inefficient use of power and the harmonic noise they throw back into the power stream. The power waveform below left (from my article) is typical of what results from the operation of a 2.5kw non Power Factor Corrected HMI & Kino load (electronic ballasts) on a conventional portable generator. The adverse effects of the severe harmonic noise exhibited here, can take the form of overheating and failing equipment, efficiency losses, circuit breaker trips, excessive current on the neutral return, and instability of the generator’s voltage and frequency. For these reasons it has never been possible to reliably operate more than a couple of 1200W HMIs on a conventional 6500W portable gas generator. Harmonic noise of this magnitude can also damage HD digital cinema production equipment, create ground loops, and possibly create radio frequency (RF) interference. The increasing use of personal computers, hard drives, and microprocessor-controlled recording equipment in production has created an unprecedented demand for clean, reliable power on set.
Left: Conventional generator power w/ pkg. of non-PFC Elec. HMI Ballasts & Kino Flo Wall-o-Lite. Right: Inverter generator power w/ Pkg. of PFC Elec. Ballasts & Kino Flo Parabeam 400.
For this reason, when your lighting package consists predominantly of non-linear light sources, like HMI and Fluorescent lights, it is important to have power factor correction (PFC) circuitry in the ballasts and operate them on inverter generators. The combination of improved power factor and the nearly pure power waveform of inverter generators makes it possible to power larger lights, or more smaller lights, than has been possible before on a small portable gas generator. For example, the power waveform above on the right, is the same 2500W load but with power factor correction operating on our modified Honda EU6500is Inverter Generator. As you can see, the difference between the resulting waveforms is startling. Even though the load is the same, the fact that it is power factor corrected and the power is being generated by an inverter generator, results in virtually no power waveform distortion. For this reason, sensitive electronic production equipment will operate reliably and without damage. And, the generator is capable of operating larger, or more smaller, lights than has ever been possible before on a portable gas generator.
For example, the substantial reduction in line noise that results from using power factor corrected ballasts on the nearly pure power waveform of an inverter generator creates a new math when it comes to calculating the load you can put on a generator. In the past we had to de-rate portable gas generators because of the inherent short comings of conventional generators with AVR and Frequency governing systems when dealing with non-PFC electronic ballasts. The harmonic distortion created by non-PFC ballasts reacting poorly with the distorted power waveform of conventional generators limited the number of HMIs you could power on a portable generator to 60% of their rated capacity (4200Watts on a 6500W Generator). But now, where inverter generators have virtually no inherent harmonic distortion or sub-transient impedance and power factor correction (PFC) is available in small HMI ballasts, this conventional wisdom regarding portable gas generators no longer holds true.
Where before you could not operate more than a couple 1200W HMIs with non-PFC ballasts on a conventional generator because of the consequent harmonic distortion, now according to the new math of low line noise, you can load an inverter generator to 100% capacity. And if the generator is our modified EU6500is inverter generator, you will be able to run a continuous load of up to 7500W on it with our 60A Full Power Transformer/Distro as long as your HMI and Kino ballasts are Power Factor Corrected.
Wide Shot of Night exterior scene lit with a pkg. consisting of PFC 2.5 & 1.2 HMI Pars, PFC 800w Joker HMI, Kino Flo Flat Head 80, 2 ParaBeam 400s, and a ParaBeam 200 powered by a modified Honda EU6500is.
According to this new math, when you add up the incremental savings in power to be gained by using only PFC HMI ballasts, add to it energy efficient sources like the Kino Flo Parabeam fixtures, and combine it with the pure waveform of inverter generators, you can run more HMI lights on a portable gas generator than has been possible before. For example, the 7500W capacity of our modified Honda EU6500is Inverter Generator can power a lighting package that consists of a PFC 2.5kw HMI Par, PFC 1200, & 800 HMI Pars, a couple of Kino Flo ParaBeam 400s, a couple of ParaBeam 200s, and a Flat Head 80. Given the light sensitivity of HD cameras, this is pretty much all the light you will need to light both the foreground and deep background of your night exterior. (For more details on how this is accomplished I suggest you read my newsletter article on the use of portable generators in motion picture production. The article is available at www.screenlightandgrip.com/html/emailnewsletter_generators.html. )
Guy Holt, Gaffer, ScreenLight & Grip, Boston
Continued from above.
To maximize the number of lights that you can run off your portable generator, I would suggest you run all your HMIs on Power Factor Corrected ballasts. This will not be easy because until recently Power Factor Correction (PFC) has not been readily available in 800 or 1200 Watt HMI ballasts in this country (the EU countries are further along in this respect), and not always available in 2500 and 4000 Watt ballasts. A name brand to ask for is Power-2-Light. Power-2-Light is the only ballast manufacturer to include Power Factor Correction (PFC) as standard in their 800w, 1200w, 2.5kw/4kw electronic ballasts. Formerly only available in the larger ballasts of other manufacturers, this advanced electronics reduces current spikes and harmonics in the power line and contributes to a more economical use of power than typical electronic ballasts. For this reason, Power-2-Light PFC electronic ballasts enable the operation of both larger HMIs, or more smaller HMIs, off of standard wall outlets and portable generators. Power-2-Light PFC ballasts, used in conjunction with our modified Honda EU6500is generator and a step-down transformer/distro, can go a long ways towards eliminating the need for large diesel generators, or dangerous tie-ins, in many situations.
Until the introduction of PFC circuitry in smaller HMI ballasts it was not possible to reliably operate more than a couple 1200W HMIs with non-PFC ballasts on a conventional generator because of the voltage waveform distortion they created. The harmonic noise that magnetic and non-PFC electronic ballasts kick back into the power stream has an adverse effect on the power waveform of conventional generators where it does not on grid power. Normally, when you plug an HMI light into a wall outlet you need not be concerned about current harmonic distortion producing voltage distortions. The impedance of the electrical path from the power plant is so low, the distortion of the original voltage waveform so small (1-3%), and the plant capacity so large, that inherently noisy loads placed upon it will not affect the voltage at the load bus.
However, it is an all together different situation when plugging HMIs and Kinos into conventional portable generators. Given the large sub-transient impedance of conventional portable generators, even a small degree of harmonic noise being fed back into the power stream will result in a distortion of its’ voltage. Add to that, the likely hood that the percentage of the generator’s capacity taken up by non-linear loads (HMI or Kino ballasts) will to be very high given its small size relative to typical lighting loads, and given the increasing prevalence of non-linear light sources (HMI & Kinos) in production. Finally, add that the original supply voltage waveform of a conventional generator is appreciably distorted to begin with, and you have a situation where the return of any harmonic currents by an HMI or Kino ballast will result in significant waveform distortion of the voltage in the distribution system.
In the past, the primary factors limiting the use of HMIs on portable generators has been their inefficient use of power and the harmonic noise they throw back into the power stream. The power waveform below left (from my article) is typical of what results from the operation of a 2.5kw non Power Factor Corrected HMI & Kino load (electronic ballasts) on a conventional portable generator. The adverse effects of the severe harmonic noise exhibited here, can take the form of overheating and failing equipment, efficiency losses, circuit breaker trips, excessive current on the neutral return, and instability of the generator’s voltage and frequency. For these reasons it has never been possible to reliably operate more than a couple of 1200W HMIs on a conventional 6500W portable gas generator. Harmonic noise of this magnitude can also damage HD digital cinema production equipment, create ground loops, and possibly create radio frequency (RF) interference. The increasing use of personal computers, hard drives, and microprocessor-controlled recording equipment in production has created an unprecedented demand for clean, reliable power on set.
Left: Conventional generator power w/ pkg. of non-PFC Elec. HMI Ballasts & Kino Flo Wall-o-Lite. Right: Inverter generator power w/ Pkg. of PFC Elec. Ballasts & Kino Flo Parabeam 400.
For this reason, when your lighting package consists predominantly of non-linear light sources, like HMI and Fluorescent lights, it is important to have power factor correction (PFC) circuitry in the ballasts and operate them on inverter generators. The combination of improved power factor and the nearly pure power waveform of inverter generators makes it possible to power larger lights, or more smaller lights, than has been possible before on a small portable gas generator. For example, the power waveform above on the right, is the same 2500W load but with power factor correction operating on our modified Honda EU6500is Inverter Generator. As you can see, the difference between the resulting waveforms is startling. Even though the load is the same, the fact that it is power factor corrected and the power is being generated by an inverter generator, results in virtually no power waveform distortion. For this reason, sensitive electronic production equipment will operate reliably and without damage. And, the generator is capable of operating larger, or more smaller, lights than has ever been possible before on a portable gas generator.
For example, the substantial reduction in line noise that results from using power factor corrected ballasts on the nearly pure power waveform of an inverter generator creates a new math when it comes to calculating the load you can put on a generator. In the past we had to de-rate portable gas generators because of the inherent short comings of conventional generators with AVR and Frequency governing systems when dealing with non-PFC electronic ballasts. The harmonic distortion created by non-PFC ballasts reacting poorly with the distorted power waveform of conventional generators limited the number of HMIs you could power on a portable generator to 60% of their rated capacity (4200Watts on a 6500W Generator). But now, where inverter generators have virtually no inherent harmonic distortion or sub-transient impedance and power factor correction (PFC) is available in small HMI ballasts, this conventional wisdom regarding portable gas generators no longer holds true.
Where before you could not operate more than a couple 1200W HMIs with non-PFC ballasts on a conventional generator because of the consequent harmonic distortion, now according to the new math of low line noise, you can load an inverter generator to 100% capacity. And if the generator is our modified EU6500is inverter generator, you will be able to run a continuous load of up to 7500W on it with our 60A Full Power Transformer/Distro as long as your HMI and Kino ballasts are Power Factor Corrected.
Wide Shot of Night exterior scene lit with a pkg. consisting of PFC 2.5 & 1.2 HMI Pars, PFC 800w Joker HMI, Kino Flo Flat Head 80, 2 ParaBeam 400s, and a ParaBeam 200 powered by a modified Honda EU6500is.
According to this new math, when you add up the incremental savings in power to be gained by using only PFC HMI ballasts, add to it energy efficient sources like the Kino Flo Parabeam fixtures, and combine it with the pure waveform of inverter generators, you can run more HMI lights on a portable gas generator than has been possible before. For example, the 7500W capacity of our modified Honda EU6500is Inverter Generator can power a lighting package that consists of a PFC 2.5kw HMI Par, PFC 1200, & 800 HMI Pars, a couple of Kino Flo ParaBeam 400s, a couple of ParaBeam 200s, and a Flat Head 80. Given the light sensitivity of HD cameras, this is pretty much all the light you will need to light both the foreground and deep background of your night exterior. (For more details on how this is accomplished I suggest you read my newsletter article on the use of portable generators in motion picture production. The article is available at www.screenlightandgrip.com/html/emailnewsletter_generators.html. )
Guy Holt, Gaffer, ScreenLight & Grip, Boston
Night Lighting: Part 5
Continued from above.
If you have other night scenes, with a number of extras, and a preponderance of warm light sources like house lights or street lamps, I would suggest that in addition to using the HMI pkg. described above to light your deep background, you bounce a large tungsten light into a 8x8 Ultra bounce as a key for a large group. The most powerful tungsten light that you will be able to run off a portable generator or power off a wall outlet is Mole’s new 5KW Tungsten Par. Unlike traditional 5KW luminaries, the Tungsten Par uses a specifically designed General Electric 5KW Tungsten Halogen lamp intended for Axial Operation. Like an HMI par, the new Mole 5KW Tungsten Par places the lamp on its side and uses a highly polished parabolic reflector and converter lenses to adjust the field of light. Mole has computer engineered the interaction of lamp, reflector and converter lens to obtain unmatched light performance. This fixture is able to achieve output comparable to a standard 14 inch 10K Fresnel, but it draws only 42 Amps (compared to a 10k’s 84 Amps).
Distro System consisting of 60A Full Power Transformer/Distro, 2-60A GPC (Bates) Splitters, 2-60A Woodhead Box. Even though the generator is 100' away to reduce noise, plug-in points remain conveniently close to set.
To power the new Mole 5KW Tungsten Par without a large diesel generator or tie in, you can use a Transformer/Distro to step down the 240V output from our modified Honda EU6500is to a single 60A/120V circuit capable of running the 42 Amp load of the 5k. A Transformer/Distro will also enable you to safely access more “house power” on your locations. It is likely that, unless the house uses natural gas, it will have a 240V Range Plug and/or Dryer Plug. A Transformer/Distro can also step down these common 240V power outlets to a single 120V circuit capable of powering bigger lights (like the 5k Tungsten Par or 4k HMI Par) , or more smaller lights, than is possible on the house 120V circuits alone. By giving you access to more “house power” through common 240V household outlets, a Transformer/Distro can eliminate the need for dangerous tie-ins or expensive tow generators. Use this link - www.screenlightandgrip.com/html/HDPP_Transformer.html - for more details on the use of Transformer/Distros to access more “house power”.
If you have it in your budget, you might consider renting two transformer/distros and two Honda EU6500is inverter generators. I have found this to be an ideal set up for many of the situations you face in indie film production. For night exteriors, you could use one generator with a transformer distro to power a 4k Par to light the deep background. The second generator with a transformer distro would power smaller HMIs and/or Kino Flos that would light your talent action area. Two generators would allow you to light both foreground & background (the sign of good production values) without having to run tons of cable. You might also consider renting a 18 Gallon Extended Run Fuel Tank for the EU6500is supplying power to the 4K Par lighting the deep background. An extendend Run Fuel Tank will run the generator for a continuous 18 hours, so that you can set it and forget it, without worrying about it running out of fuel in the middle of a shot (use this link for more details http://www.screenlightandgrip.com/html/HDPP_Ext_Fuel_Tank.html.)
Where “house power” is available, you can use one of the transformers on a 240V range or dryer receptacle to power a 5k Tungsten Par; while using the other transformer to run a 4k Par along with a 1200 Par on the Honda 6500is to light the deep background and back edge your extras. I have used this same combination of wall outlets, 60A step-down transformer/distros, and modified Honda EU6500is generators to eliminate the need for tie-ins or a tow genny on many of the historical documentaries I have gaffed. For example, I have used this same package repeatedly at a historical mansion in Easton MA called the Ames Estate.
(Scene from "Unsolved History" powered from 50A/240V outlet through step-down transformer/distro)
A popular state fee free location, the Ames Estate, like many historical house/museums, does not permit tie-ins and the electrical wiring in the house is so antiquated that it is unusable. Fortunately, they have a 50A/240 volt circuit in the carriage house for a welder they use to repair the mowers they use at the park. Our standard mode of operation when shooting there is to run 250V extension cable from the welding receptacle to a 60A Full Power Transformer/Distro placed in the entry hall of the house. Using a 60A Siamese at the Transformer/Distro, we then run 60A 6/3 Bates extensions, down to the library, to the second floor, and back to the maid’s pantry. At the end of each run we put another 60A Siamese. A 60A Snack-box on one side of the Siamese gives us 20A branch circuits. The other side we leave open for a large HMI or Tungsten Light. Now we can safely plug 1200 & 2500W HMIs, or even a 5k Quartz, into our own distribution anywhere in the house.
(Typhoid Mary in quarantine on an island in New York's East River. Note the view out the window of the East River shoreline at the turn of the century.)
To maintain continuity between shots on these dramatic historical recreations, we usually bring a 4kw HMI Par in a window on one side of the room as a sun source and a 1200 par through a window on the other side as a northern light source. We usually power both heads off of a Honda EU6500is through a second 60A Full Power Transformer/Distro. Since the Honda EU6500is can be placed right on the lawn, we are saved from running hundreds of feet of feeder back to a tow generator in the drive.
(The exterior of the actual location used for the quarantine island. A 30' blowup of a picture of the East River at the turn of the century was rigged outside the windows of a house in Arlington MA.)
We have been able to use this same basic distribution package at numerous museums and historical houses throughout New England including Sturbridge Village. Fortunately for us, to make ends meet, many historical houses rent themselves out for events and weddings. For that reason, they usually have at least one updated service with 30 or 50 Amp 240 volt circuit for the warming ovens of caterers. I have included several production stills from these shows. Use this link - http://www.screenlightandgrip.com/html/HDPP_Transformer.html - for more production stills of PBS and History Channel historical documentaries shot entirely, or in part, with our 60A Full Power Transformer/Distro at the Ames Estate.
Guy Holt, Gaffer, ScreenLight & Grip, Boston
Continued from above.
If you have other night scenes, with a number of extras, and a preponderance of warm light sources like house lights or street lamps, I would suggest that in addition to using the HMI pkg. described above to light your deep background, you bounce a large tungsten light into a 8x8 Ultra bounce as a key for a large group. The most powerful tungsten light that you will be able to run off a portable generator or power off a wall outlet is Mole’s new 5KW Tungsten Par. Unlike traditional 5KW luminaries, the Tungsten Par uses a specifically designed General Electric 5KW Tungsten Halogen lamp intended for Axial Operation. Like an HMI par, the new Mole 5KW Tungsten Par places the lamp on its side and uses a highly polished parabolic reflector and converter lenses to adjust the field of light. Mole has computer engineered the interaction of lamp, reflector and converter lens to obtain unmatched light performance. This fixture is able to achieve output comparable to a standard 14 inch 10K Fresnel, but it draws only 42 Amps (compared to a 10k’s 84 Amps).
Distro System consisting of 60A Full Power Transformer/Distro, 2-60A GPC (Bates) Splitters, 2-60A Woodhead Box. Even though the generator is 100' away to reduce noise, plug-in points remain conveniently close to set.
To power the new Mole 5KW Tungsten Par without a large diesel generator or tie in, you can use a Transformer/Distro to step down the 240V output from our modified Honda EU6500is to a single 60A/120V circuit capable of running the 42 Amp load of the 5k. A Transformer/Distro will also enable you to safely access more “house power” on your locations. It is likely that, unless the house uses natural gas, it will have a 240V Range Plug and/or Dryer Plug. A Transformer/Distro can also step down these common 240V power outlets to a single 120V circuit capable of powering bigger lights (like the 5k Tungsten Par or 4k HMI Par) , or more smaller lights, than is possible on the house 120V circuits alone. By giving you access to more “house power” through common 240V household outlets, a Transformer/Distro can eliminate the need for dangerous tie-ins or expensive tow generators. Use this link - www.screenlightandgrip.com/html/HDPP_Transformer.html - for more details on the use of Transformer/Distros to access more “house power”.
If you have it in your budget, you might consider renting two transformer/distros and two Honda EU6500is inverter generators. I have found this to be an ideal set up for many of the situations you face in indie film production. For night exteriors, you could use one generator with a transformer distro to power a 4k Par to light the deep background. The second generator with a transformer distro would power smaller HMIs and/or Kino Flos that would light your talent action area. Two generators would allow you to light both foreground & background (the sign of good production values) without having to run tons of cable. You might also consider renting a 18 Gallon Extended Run Fuel Tank for the EU6500is supplying power to the 4K Par lighting the deep background. An extendend Run Fuel Tank will run the generator for a continuous 18 hours, so that you can set it and forget it, without worrying about it running out of fuel in the middle of a shot (use this link for more details http://www.screenlightandgrip.com/html/HDPP_Ext_Fuel_Tank.html.)
Where “house power” is available, you can use one of the transformers on a 240V range or dryer receptacle to power a 5k Tungsten Par; while using the other transformer to run a 4k Par along with a 1200 Par on the Honda 6500is to light the deep background and back edge your extras. I have used this same combination of wall outlets, 60A step-down transformer/distros, and modified Honda EU6500is generators to eliminate the need for tie-ins or a tow genny on many of the historical documentaries I have gaffed. For example, I have used this same package repeatedly at a historical mansion in Easton MA called the Ames Estate.
(Scene from "Unsolved History" powered from 50A/240V outlet through step-down transformer/distro)
A popular state fee free location, the Ames Estate, like many historical house/museums, does not permit tie-ins and the electrical wiring in the house is so antiquated that it is unusable. Fortunately, they have a 50A/240 volt circuit in the carriage house for a welder they use to repair the mowers they use at the park. Our standard mode of operation when shooting there is to run 250V extension cable from the welding receptacle to a 60A Full Power Transformer/Distro placed in the entry hall of the house. Using a 60A Siamese at the Transformer/Distro, we then run 60A 6/3 Bates extensions, down to the library, to the second floor, and back to the maid’s pantry. At the end of each run we put another 60A Siamese. A 60A Snack-box on one side of the Siamese gives us 20A branch circuits. The other side we leave open for a large HMI or Tungsten Light. Now we can safely plug 1200 & 2500W HMIs, or even a 5k Quartz, into our own distribution anywhere in the house.
(Typhoid Mary in quarantine on an island in New York's East River. Note the view out the window of the East River shoreline at the turn of the century.)
To maintain continuity between shots on these dramatic historical recreations, we usually bring a 4kw HMI Par in a window on one side of the room as a sun source and a 1200 par through a window on the other side as a northern light source. We usually power both heads off of a Honda EU6500is through a second 60A Full Power Transformer/Distro. Since the Honda EU6500is can be placed right on the lawn, we are saved from running hundreds of feet of feeder back to a tow generator in the drive.
(The exterior of the actual location used for the quarantine island. A 30' blowup of a picture of the East River at the turn of the century was rigged outside the windows of a house in Arlington MA.)
We have been able to use this same basic distribution package at numerous museums and historical houses throughout New England including Sturbridge Village. Fortunately for us, to make ends meet, many historical houses rent themselves out for events and weddings. For that reason, they usually have at least one updated service with 30 or 50 Amp 240 volt circuit for the warming ovens of caterers. I have included several production stills from these shows. Use this link - http://www.screenlightandgrip.com/html/HDPP_Transformer.html - for more production stills of PBS and History Channel historical documentaries shot entirely, or in part, with our 60A Full Power Transformer/Distro at the Ames Estate.
Guy Holt, Gaffer, ScreenLight & Grip, Boston