Everything you need to know about Inverters: Part 5
Cont. from above
The Honda EU6500is inverter generator is much quieter than the movie blimped Honda EX5500. Part of what makes the new Honda EU6500is so quiet is it's "Eco-Throttle." "Eco-Throttle" is Honda's trade name for a feature of inverter generators already discussed. It is the name Honda give to the fact that the generator's microprocessor automatically adjusts the generator's engine speed to produce only the power needed for the applied load. It can do this because the PWM inverter of the Honda EU6500is enables it to run at different RPMs and maintain a constant frequency and voltage. Where conventional generators like the Honda EX5500 and ES6500 have to run full speed at a constant 3600 RPM to produce stable 60 hertz (cycle) electricity, a Honda EU6500is only needs to run as fast as required to meet the load demand. Since their engines do not have to run at full speed, and the fact that an inverter generator generates 20% more power per revolution of the engine, makes the Honda EU6500is inverter generator substantially quieter than conventional models. To make them even quieter, Honda has designed a new separate triple chamber construction and a new centralized intake/exhaust system. The net result is that the EU6500is is half as loud (ten decibels) as the comparable EM7000is and ES6500 generators typically found at lighting rental houses. Honda's EU Series generators operate at 34 to 44 dBA at 50 ft. - well below what is required for trouble free location recording and quieter than your typical Crawford 1400 Amp "Movie Blimped" Generator. With sound specs this good all you need to record sound without picking up generator noise is a real distro system that will allow you to move the generator off set but yet keep your plug-in pockets conveniently on set.
My company, ScreenLight & Grip (SL&G), has developed a Gen-set that is designed to take advantage of the benefits of "True Sine Wave" Inverter genertors and recent technological advances in HMI ballast design to create clean stable set power that is capable of operating larger lights (HMIs up to 6kw or Quartz lights up to 6kw), or more smaller lights, off of portable gas generators than has ever been possible before. What we do is tap the Honda EU6500is inverter generator as it is designed for 230/240V markets like the UK, EU, Australia, & India (to name just a few.) By doing so, we gain access to the full 7650 Watt power capacity designed into the generator for these 230/240V markets, but not available in generators manufactured for 120V Markets like North America. We then use a proprietary step-down transformer/distro to convert the full 240V power into a single 60A/120V circuit (7500Watts) capable of power large lights. Finally, where PWM inverter generators, like the Honda EU6500is, generate a nearly pure power waveform, our modified Honda EU6500is is capable of reliably powering more lights than has been possible before.
To maximize the number of HMI & fluorescent lights that can run off our modified Honda EU6500is inveter generator, we offer HMIs and Kino Flo lights with Power Factor Corrected ballasts. For those of you not familiar with Power Factor Correction (PFC), a PFC circuit utilizes a RF Mains Filter to restrict the flow of harmonic currents back onto the supply service. In this fashion, the PFC circuit realigns voltage and current and induces a smoother power waveform at the distribution bus. Formerly only available in large HMI ballasts this advanced electronics reduces voltage waveform distortion and contributes to a more economical use of power than typical HMI and fluorescent electronic ballasts.
The substantial reduction in line noise that results from using PFC 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 portable gas generator. In the past we had to de-rate portable generators because of the inherent short comings of conventional generators when dealing with non-PFC electronic ballasts. The voltage waveform 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). The power waveform below left (from my article) is typical of what results from the operation of a 2500W non-Power Factor Corrected load (electronic HMI & Kino ballasts) on a conventional portable generator (a Honda EX5500 with a Barber Coleman Governor.) The adverse effects of the severe harmonic noise exhibited here - overheating and failing equipment, efficiency losses, circuit breaker trips, excessive current on the neutral return, and instability of the generator's voltage and frequency - limits the number of non-PFC HMIs and Fluorescent lights you can reliably operate on the generator.
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 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 on the same power. And, the generator is capable of operating larger, or more smaller, lights than has ever been possible before on a portable gas generator.
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.
The extremely low low line noise exhibited in the inverter generator power waveform above (right) creates a new math when it comes to calculating the lighting load you can put on a portable generator. 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 you can load an inverter generator to capacity. And if the generator is one of our modified Honda EU6500is inverter generators, you will be able to run a continuous load of up to 7500W as long as your HMI and Kino ballasts are Power Factor Corrected.
The PFC 2.5 & 1.2 HMI Pars, PFC 800w Joker HMI, Kino Flo Flat Head 80, 2 ParaBeam 400s, and a ParaBeam 200 of our HD P&P Pkg. powered by our modified Honda EU6500is through our 60A Full Power Transformer/Distro
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 night exteriors. For more details on how this is accomplished I suggest you read the article I wrote for our company newsletter (mentioned above) on the use of portable generators in motion picture production. Since, the power issues it discusses have been vexing set electricians for years, I highly recommend that anyone responsible for generating power on a set, whether large or small, read this article. The article is available at
www.screenlightandgrip.com/html/emailnewsletter_generators.html.)
A Distro System consisting of a 60A Full Power Transformer/Distro, 2-60A GPC (Bates) Splitters, 2-60A Woodhead Box distributes power from a modified Honda EU6500is. Even though the generator is 100' away to reduce noise, plug-in points remain conveniently close to set.
If tie-ing marine cells into the alternator of a car doesn't give you sufficient power, I would highly recommend our new Gen-set system. The generator is super quiet. The transformer/distro gives you access to more power (7500 Watts continuous)in a larger 60A/120V circuit that is capable of power larger lights or more smaller lights than has ever been possible on a portable gas generator. Use this
link for more information about using inverter generators with transformers for motion picture lighting.
Guy Holt, Gaffer, ScreenLight & Grip, Boston