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Generators for a Low Budget feature film


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#1 Thomas Chaves

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Posted 02 October 2009 - 09:46 PM

Hey there everyone.

This upcoming Novemeber, I'll be key gripping on a feature and the producer is debating whether to rent or buy a generator. Ideally, we would like to have a 5500W generator.

The average price for a Honda 5500W is about $200/day. I know Honda makes solid generators because I've used them on a number of shoots.

Today, while I was at Home depot, I saw a bunch of generators ranging between 5500-8000W going for $900-$1300. The brands were Ridged, Husky, & Yamaha. Have any of you guys ever used these generators on your shoots? Are they trust worthy?

What do you guys recommend?

Thanks.

Thomas Chaves

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#2 Daniel Wallens

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Posted 02 October 2009 - 10:00 PM

The first question to be answered is, if you are key gripping this thing, why on earth are you dealing with generators at all?

-DW


(and really, this shouldn't be in the Gripping section)
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#3 Matthew W. Phillips

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Posted 02 October 2009 - 10:10 PM

The first question to be answered is, if you are key gripping this thing, why on earth are you dealing with generators at all?

-DW


(and really, this shouldn't be in the Gripping section)


I was thinking the same way! That's the Electrical department (unless this is a super small shoot where grips double as electricians...ouch!)
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#4 monday sunnlinn

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Posted 04 October 2009 - 12:36 PM

the quality of the power the home depot gennies make is dangerous to sensitive electronics and lighting elements...

this was informative for me...

http://www.screenlig...generators.html

just keep in mind that a rental company posted this...so it might be somewhat biased...
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#5 Paul Bruening

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Posted 04 October 2009 - 10:37 PM

If you're going to buy, buy something with iron jugs. Aluminum jugs wear down and out too fast. All of those gennies with Briggs and Stratton engines are usually aluminum.

I'd recommend relocating to places where you can tie-in. But, then you get into all that electricity-is-the-devil stuff and will need someone who knows how to grab that tiger by the tail.
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#6 John Sprung

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Posted 05 October 2009 - 07:32 PM

Small portable generators like that are primarily used by building contractors to run power tools before the temp pole is in. What I gather from them, the best bang for your buck would be:

1. Army surplus "6 Horsepower" generators. They produce much more than the rated output, and are built to go thru a war. Find 'em on e-bay, etc. Check that you're getting 120/240 Volts AC, as some are low voltage DC.

2. Honda

3 Wacker with the Honda engine

4. Onan

The more people you have on your cast and crew, the more reliable your generator needs to be.




-- J.S.
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#7 JD Hartman

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Posted 10 November 2009 - 07:27 PM

Small portable generators like that are primarily used by building contractors to run power tools before the temp pole is in. What I gather from them, the best bang for your buck would be:

1. Army surplus "6 Horsepower" generators. They produce much more than the rated output, and are built to go thru a war. Find 'em on e-bay, etc. Check that you're getting 120/240 Volts AC, as some are low voltage DC.

2. Honda

3 Wacker with the Honda engine

4. Onan

The more people you have on your cast and crew, the more reliable your generator needs to be.




-- J.S.


Just my experience from hands-on with the EU series Hondas, they aren't quiet. They are better than a construction type genny, but not whisper quiet. There are no small engines that I'm aware of with cast iron blocks or liners, except the older engines like the Onan CK series
My list:
1) Onan: NH,NHC, NHE series 2) Kohler 3) Army surplus 4) Honda
The Yahamas, Kawis, Subarus, Coleman, Powermate (powermaybe) or anything sold at Home Dee, Lowes, etc. is just junk.

If you can't get a good long term rental deal for a small generator, I'd consider buying one for the production.
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#8 Phil Rhodes

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Posted 10 November 2009 - 08:25 PM

the quality of the power the home depot gennies make is dangerous to sensitive electronics and lighting elements


No, that's not what it says - what it actually says is that HMI ballasts without power-factor correction are dangerous to more or less everything else, which is extremely true.

The only behaviour I've ever seen on a film set that was dangerous to equipment was the electrical department's idle mindlessness with regard to properly earthing generators, which can result in poor unfortunate pieces of mains-powered video equipment which happen to be in contact with a grounded conductive object being asked to sink the earth leakage of every HMI ballast on the job down the video screen.

To drag the discussion even further offtopic the attitude seems to be that if you can't get a "proper" earth, where "proper" expands to "the solution causing whatever degree of difficulty the electrician requires to justify his excuse not to do it", it isn't worth bothering at all.

It is.

But to return to that article: this can "damage HD...equipment?" Well, actually, most of that stuff runs very capable switch-mode power supplies which are extremely good at avoiding problems with dirty mains, and by that metric, it's as likely to damage a $2500 DV palmcorder as a $250,000 D-cinema camera. I wonder if they're scaremongering.

And create ground loops? Christ, that's a good trick. Exploit ground loops, well, perhaps, but actively create ground loops? This is absolute unmitigated and completely partisan pigswill.

P
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#9 Keith Walters

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Posted 10 November 2009 - 10:47 PM

But to return to that article: this can "damage HD...equipment?" Well, actually, most of that stuff runs very capable switch-mode power supplies which are extremely good at avoiding problems with dirty mains, and by that metric, it's as likely to damage a $2500 DV palmcorder as a $250,000 D-cinema camera. I wonder if they're scaremongering.

Even so I would strongly recommend some sort of protected power distribution board, of the type that are readily available from electronics retailers. You generally get what you pay for, (except of course in specialist HiFi stores that cater to your briar-pipe tweed-jacket overstuffed-leather-armchair types looking for $90,000 valve amplifiers and $5,000 speaker leads :lol: )

In my experience, the biggest killer of electronic power supplies is the situation where someone has hired or bought the cheapest DIY-R-US generator they can find, and then used it to run both high-power lights and electronic equipment. The problem is that although a lot of those generators have reasonable voltage regulation, it works much the same way as a car's alternator: DC is supplied to a rotating electromagnet that generates the AC output; varying this current controls the output voltage.

Trouble is the magnetic field can't drop instantly to zero, so if there is a very large load attached to the circuit, when you switch that off, the output voltage can surge violently for a second or so, which is enough fry a lot of electronic power supplies. A commonly lethal combination is a hairdryer in parallel with an electronic appliance, because hairdressers repeatedly switch them on and off.

The very best compact generators actually generate DC and have a built-in sinewave inverter that converts it to the AC output, but of course these cost a lot more.

Generally, it is pretty easy to identify a piece of equipment that has been damaged by high mains voltages, so if you blow up a rental item, you're likely to find yourself paying for an insurance excess, if not the entire repair.
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#10 Phil Rhodes

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Posted 11 November 2009 - 08:45 AM

Yes sure.

But that's as likely to damage anything as it is to damage HD gear.

They're just trying to make it sound impressive :angry:

P
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#11 Jamie Metzger

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Posted 13 November 2009 - 11:43 PM

we used a honda 6500 EU series, and it worked just fine. if I were you, I'd figure out how much it costs vs how many days of rental vs $200/day and beat that price. You might just make your money back and then some, and then you have a generator for yourself.
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#12 Guy Holt

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Posted 17 December 2009 - 04:10 PM

But to return to that article: this can "damage HD...equipment?" Well, actually, most of that stuff (electronic production equipment) runs very capable switch-mode power supplies which are extremely good at avoiding problems with dirty mains,l[/i].


It has been suggested in this thread that the motives for my posts are suspect because "a rental company posted this...so it might be somewhat biased..." I would like to make clear that I post as a professional gaffer and can offer the following credentials:

IATSE Local 481 Certified Generator Operator

Certificate Holder of the MQ Power "MQP Special Generator (Crawford) Technical Service Seminar"

Gaffer, Set Electrician, and Generator Operator on numerous features and television productions (for a partial list of credits see my imdb listing at http://www.pro.imdb....name/nm1471247)

Owner of ScreenLight & Grip, a lighting and grip rental company renting Honda, MQ, and Crawford generators for motion picture production for 18 years.

But, don't take just my word that harmonic currents can cause problems for switch-mode power supplies: according to the Caterpillar Application and Installation Guide for "Electric Power Applications, Engine and Generator Sizing" *: "Most loads will continue to operate with THD at 15 to 20%. However, loads with sensitive electronic equipment can develop problems with THD greater than 5%." The THD value of the severe voltage waveform distortion, generated by two 1200 Pars (with non-PFC ballasts) operating on a conventional AVR gas generator, that can been seen in the oscilloscope shots in my article (available at www.screenlightandgrip.com/html/emailnewsletter_generators.html) is well over 100%. There is no question that THD values of this magnitude in a power waveform will cause erratic behavior in other equipment running on the same distribution system.

But don't just take my word for it. Here is a bit of anecdotal evidence relayed to me by Dave Talamas, the owner and chief engineer, of Talamas Broadcast Systems, in Newton Ma.: they sent several non-linear editing systems to the Iron Man Triathlon for field editing. The laptops kept inexplicably locking up. They put a scope meter on the power supply which was coming from a generator that was also supplying a large number of HMIs and found the voltage waveform was severely distorted. They moved the lap tops to the onboard generator of a satellite truck. Once they were moved from the highly distorted power supply of the lighting generator to the highly refined power supply of the satellite truck the laptops operated flawlessly. This incident clearly demonstrates that the switch-mode power supplies of production equipment are not as extremely good at avoiding problems with dirty mains, as Phil suggests. If you like I can present plenty more anecdotal evidence that harmonic currents kicked back into the power stream by HMI & Kino ballasts can cause problems on set. There is simply no question that THD values of this magnitude seen in the power waveforms in my article will cause such adverse effects such as overheating, circuit breaker trips, high currents on the neutral wire, and instability of the generator voltage and frequency. There is also no question that the severe harmonic noise exhibited in my oscilloscope shots can damage HD digital cinema production equipment, create ground loops, and create radio frequency (RF) interference.


And create ground loops? Christ, that's a good trick. Exploit ground loops, well, perhaps, but actively create ground loops? This is absolute unmitigated and completely partisan pigswill.


It is a well established fact that ground looping can be caused by total harmonic distortion of the magnitude we see in my oscilloscope shots. As Tomi Engdahl establishes in "Ground loop problems and how to get rid of them" ** current on neutral conductors with a high THD value will induce voltage in ground wires greater than the 2 volt maximum stipulated by IEEE Standard 1100-1992 (Recommended Practice for Powering and Grounding Sensitive Electronic Equipment.) To paraphrase Tomi Engdahl: neutral-to-ground voltages cause current to flow on the ground wires and under the right circumstances can lead to the creation of ground loops betweeen the tethered components of a production package. The circumstances under which a ground loop will occur is when there is more than one ground connection path between two pieces of equipment. The duplicate ground paths form the equivalent of a loop antenna that very efficiently picks up interference currents. Lead resistance transforms these currents into voltage fluctuations. As a consequence of ground loop induced voltages, the ground reference in the system is no longer a stable potential (a floating ground), so the signals ride on the noise. The noise becomes part of te program signal. The result is that the unwanted signal will be amplified until it is audible and clearly undesirable.

Small voltage differences just cause noise to be added to the signals. This can cause an audio hum, interference bars to video signals, and transmission errors in computer networks. Higher currents can cause more serious problems that can damage equipment like sparking in connections and burned wiring. As more and more electronic components, like lap top computers, hard drives, and HD monitors, are integrated into the typical location HD production package, ground loops become more of a hazard.

I wonder if they're scaremongering.


I'm not scare-mongering when I warn that harmonic currents can cause problems for electronic production equipment. But again, don't just take my word for it: apparently, harmonics when using a generator for lighting is enough of a problem to warrant several sections in the third edition of the "Set Lighting TechnicianĂ­s Handbook." *** To quote Harry Box (Page 337 under "Power Problems from Electronic Loads"):

"Much of today's lighting technology relies on electronics such as DC rectifiers (electronic HMI ballasts), silicone-controlled rectifiers (SCRs), capacitors (magnetic & electronic HMI ballasts), and high-frequency switching power supplies (the IGBTs of electronic ballasts). These kinds of load can have undesirable effects on the current waveform, revealing themselves in the form of overheating or failing equipment , efficiency losses, circuit breaker trips, excessive current on the neutral wire, interference and instability with generators, noisy or overheating transformers and service equipment, and even loosened electrical connections. In the following sections, we discuss the power factor and current harmonics and look at their effects. Your awareness of these effects will help you to build systems that avoid or mitigate problems and show how to test for problems.(the parenthesis are mine)"

Now does this sound like harmonics is not a problem when using a generator for lighting and I am just "scaremongering"? Or, does Phil want to also accuse Harry Box of trying to scare the ignorant public into buying a solution to a problem that doesn't exist. The problem exists. Now you can either deny it and be worse off for it; or as Harry Box suggests, you can accept it and "your awareness of these effects will help you to build systems that avoid or mitigate problems (on set.)" Which, incidentally, is all that I have tried to do in my posts.

Harmonic distortion has just recently become a problem because small conventional generators like the Honda ES6500 and EX6500 were not designed to deal with the abundance of non-linear loads like electronic HMI and Kino Flo ballasts in use today. Running incandescent lights on these generators was never a problem because as purely resistive loads they didnĂ­t create harmonic currents. While the inductive reactance of magnetic ballasts running on these generators created voltage spikes, they operated pretty reliably if the generator was equipped with an AC frequency governor. The problem began with the increasing use of non-linear lighting loads, like electronic HMI and Kino Flo ballasts, that generate harmonic currents. The problem is being further compounded by the increasing prevalence on set of sophisticated electronic production equipment like computers, hard drives, and HD monitors which require clean stable power to operate, but are themselves sources of harmonic distortion. Where in the past, much attention was given to portable generator features such as automatic voltage regulation, speed regulation and AC Frequency. Given the increasing prevalence of harmonic currents and the problems they cause, an increasingly more important feature today is the quality of the generated waveform.

I have put many hours into researching generators, the harmonic noise generated by electronic ballasts, and the adverse effect it has on set power because I have run into them repeatedly in my professional life as a Gaffer and Generator Operator. I have spent many more hours trying to put what I have learned down in writing so that others can benfit by it as well. I have made this information available for free in this forum rather than selling it to a trade magazine or publisher that would make you pay for it. Finally, I have gone to great length to explain the electrical engineering principles behind our new gen-set system to show that the claims I make are not " somewhat biased...." And, as I think I have demonstrated without a doubt in this post, it is not so much "pigswill."

To return to the topic of this thread:

while I was at Home depot, I saw a bunch of generators ranging between 5500-8000W going for $900-$1300. The brands were Ridged, Husky, & Yamaha. Have any of you guys ever used these generators on your shoots? Are they trust worthy?



Thomas, so that you don't have to take my word alone on this issue, it has been heavily discussed on RedUser.net ( see http://reduser.net/f...ead.php?t=24768

- Guy Holt, Gaffer, ScreenLight & Grip, Boston

* Caterpillar. "Application and Installation Guide for Electric Power Applications, Engine and Generator Sizing (CAT publication LEBE5294." (Online) Availabe at the Caterpillar Electronic Media Center.

**Engdahl, Tomi. "Ground loop problems and how to get rid of them." (Online) Available www.blueguitar.org/new/articles/other/ground_loop.pdf,1997-2000

*** Box, Harry. Set Lighting Technician's Handbook, Third Edition. London: Elsevier Press, 2008
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#13 David Rakoczy

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Posted 17 December 2009 - 04:21 PM

What you say makes sense. Though, we have and continue to use the 'Lowes' & 'Home Depot' models as well. Without issue (so far).

You wouldn't happen to be related to the famous Hollywood Gaffer Gary Holt would you? I used to room with his son Kenny.
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#14 Guy Holt

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Posted 17 December 2009 - 05:41 PM

What you say makes sense. Though, we have and continue to use the 'Lowes' & 'Home Depot' models as well. Without issue (so far). You wouldn't happen to be related to the famous Hollywood Gaffer Gary Holt would you?


Unfortunately for me, there is no relation. And you are right that every tool has an application. The added expense of a Honda EU6500is is not necessary if you are not recording sound and using predominantly tungsten light instruements.

Just my experience from hands-on with the EU series Hondas, they aren't quiet. They are better than a construction type genny, but not whisper quiet.


In my experience, when you do need to power HMI & Kino ballasts and record clean audio tracks a Honda EU6500is can do the job. It comes down to how you use the generator. If you know how to use it, it is possible to record location audio without picking up generator noise - especially if you use them with a transformer. The Honda EU6500is inverter generator to begin with is much quieter than the older movie blimped Honda EX5500. Part of what makes the new Honda EU6500is so quiet is it's "Eco-Throttle." The Eco-Throttle'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 inverter technology 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 given the fact that an inverter generator generates 20% more power per revolution of the engine, makes the Honda EU series of inverter generators substantially quieter than conventional models.

The net result is that the EU6500is operates between 34 to 44 dBA at 50 ft. - half as loud (ten decibels) as the comparable EM7000is and ES6500 generators and comparable to our Crawford 1400A. But you can't park a Crawford right on set and record sound without picking up the generator either. 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 EU6500is off set (like you would a Crawford), minimize line loss over a long cable run, and provide plug-in pockets conveniently close to set. That is where the transformer comes in.

My company, ScreenLight & Grip (SL&G), has developed a Gen-set that is designed to provide clean quiet set power from a modified Honda EU6500is. 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 the US. We then use a proprietary step-down transformer/distro we have developed to convert the full 240V power into a single 60A/120V circuit (7500Watts) capable of powering large lights. And, 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. Finally, to record sync sound without picking up any generator noise, all you need to do is add 100' - 150' of heavy duty 250V twist-lock extension cable between the generator and our Full Power Transformer/Distro. This is usually enough cable to place the generator around the corner of a building, or to run it out of a van or truck - which is usually all the additional blimping you need with these generators. The heavy-duty 250V twist-lock cable eliminates multiple long cable runs to the generator and minimizes line-loss; as well as, eliminates the voltage drop you would have using standard electrical cords.

Posted Image
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.


To assure full line level (120V) on set, our 60A Full Power Transformer/Distro is designed to compensate for the slight line loss you will have over an extended cable run. That is, it is designed to slightly boost the voltage on the load side (secondary) so that if you were to feed the supply side (primary) of the transformer 240 volts from the generator, 127 volts would come out on the secondary side where you plug in the lights. This slight boost enables you to place the generator further from set where you won't hear it, yet assure that the supply voltage on set does not drop too low. Our 60A Full Power Transformer/Distro is equipped with a 60A Bates and three 20 A Edison circuits so that you have plug-in pockets conveniently on set.

Posted Image
60A GPC (Bates) Splitters and Woodhead Box.


Our new 60A Full Power Transformer/Distro offers a number of other benefits as well. Without our Transformer/Distro you can never fully utilize the full power of the generator because the load of a light has to go on one circuit/leg of the generator or the other. For example, when plugging lights into the factory installed power outlet panel of a Honda EU6500is, you quickly reach a point where you can't power an additional 1200W HMI because there is not 11.5 amps (w/ a PFC ballast) available on either one of the factory installed 20A outlets/leg of the generator. With our Full Power Transformer/Distro you can still add that 1200W HMI because the Transformer/Distro not only accesses more power (7500 Watts) through a higher rated circuit (60 Amps), but it also splits the load evenly over the two legs (5.75A/leg) of the generator. The end result is that the generator is capable of handling a larger load more easily because it is a perfectly balanced load.

Posted Image
60A Woodhead Box running Power-to-Light PFC 800W ballast (left) and PFC 1200W ballast (right.)


Another benefit to using our Transformer/Distro is that it greatly simplifies set electrics by splitting the load of what ever you plug into it automatically. This means you no longer have to carefully balance the load over the generator's two 20A/120 circuits/legs as you plug in lights because the Transfomer/Distro does it for you. With our modified Honda EU6500is you simply plug in lights until the load wattage displayed on the generator's iMonitor reaches 7500 Watts. Now that you are able to fully utilize the generator's available power, you are able to power larger lights, or more smaller lights, than you could without a transformer/distro. For more details on the use of transformers for set power, I suggest you read the article I wrote for our company newsletter (mentioned above) on the use of portable generators in motion picture production. Use this link - www.screenlightandgrip.com/html/emailnewsletter_generators.html for more information about using inverter generators with transformers for motion picture lighting.

Guy Holt, Gaffer, [url="http://www.screenlightandgrip.com""] ScreenLight & Grip [/url], Boston
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#15 John Sprung

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Posted 17 December 2009 - 08:41 PM

The only behaviour I've ever seen on a film set that was dangerous to equipment was the electrical department's idle mindlessness with regard to properly earthing generators, ....


Yes, absolutely, generators should be properly grounded. Even if you're out in the middle of some soggy wilderness, pound a couple yards of re-bar into the ground and bond to it. That gives your GFCI's a fighting chance to do their job. If you're anywhere near mains power, bond to its ground.

Grounding is like the seat belts and air bags in your car. 99+% of the time, you'd get there just fine with or without them. But once in a great while, they save your life.




-- J.S.
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#16 Hal Smith

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Posted 17 December 2009 - 09:48 PM

Yes, absolutely, generators should be properly grounded. Even if you're out in the middle of some soggy wilderness, pound a couple yards of re-bar into the ground and bond to it. That gives your GFCI's a fighting chance to do their job. If you're anywhere near mains power, bond to its ground.

Grounding is like the seat belts and air bags in your car. 99+% of the time, you'd get there just fine with or without them. But once in a great while, they save your life.


More Hal Smith arcane knowledge: If you're in a situation where you need an absolutely bulletproof ground and there's money to burn, have a local water well outfit drill a well to 40-50' below the water table and drop enough 4" copper strap into it to get to the bottom of the well. That'll give you a ground that can take a lightning strike and hardly notice it. Recommended for rocky terrain, sand, and all the other situations where ground rods are a joke. I've fixed tower installations with that method that nothing else had stopped recurrent lightning damage.

PS: If you've got a friendly power company around, ask them to drive your ground rods. Line trucks often have a hydraulic ground rod installer on them that shoves them into the ground in about ten seconds flat.
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#17 John Sprung

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Posted 18 December 2009 - 12:37 AM

PS: If you've got a friendly power company around, ask them to drive your ground rods. Line trucks often have a hydraulic ground rod installer on them that shoves them into the ground in about ten seconds flat.


Before the big drought, I sank a ground rod by the "hydraulic" method that I learned from a guy who used to use it on Mt. Wilson for big TV transmitter grounds. I had room to support a piece of pipe about 30 ft. vertically, so I put together 30 ft. of 1" type K copper with a 3/4 NPT female on the top end, and the bottom end hammered almost flat. I ran a hose to the top, and had it on a rope and pully rig to lower it as the water washed out a path. It took about six hours to sink that thing 30 ft. into the ground, but it sure makes an excellent ground. Plus, an inspector can take the brass plug out of the top end and run a tape down inside to check how far it goes.



-- J.S.
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#18 Brian McGee

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Posted 18 December 2009 - 10:35 AM

Unfortunately for me, there is no relation. And you are right that every tool has an application. The added expense of a Honda EU6500is is not necessary if you are not recording sound and using predominantly tungsten light instruements.



In my experience, when you do need to power HMI & Kino ballasts and record clean audio tracks a Honda EU6500is can do the job. It comes down to how you use the generator. If you know how to use it, it is possible to record location audio without picking up generator noise - especially if you use them with a transformer. The Honda EU6500is inverter generator to begin with is much quieter than the older movie blimped Honda EX5500. Part of what makes the new Honda EU6500is so quiet is it's "Eco-Throttle." The Eco-Throttle'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 inverter technology 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 given the fact that an inverter generator generates 20% more power per revolution of the engine, makes the Honda EU series of inverter generators substantially quieter than conventional models.

The net result is that the EU6500is operates between 34 to 44 dBA at 50 ft. - half as loud (ten decibels) as the comparable EM7000is and ES6500 generators and comparable to our Crawford 1400A. But you can't park a Crawford right on set and record sound without picking up the generator either. 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 EU6500is off set (like you would a Crawford), minimize line loss over a long cable run, and provide plug-in pockets conveniently close to set. That is where the transformer comes in.

My company, ScreenLight & Grip (SL&G), has developed a Gen-set that is designed to provide clean quiet set power from a modified Honda EU6500is. 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 the US. We then use a proprietary step-down transformer/distro we have developed to convert the full 240V power into a single 60A/120V circuit (7500Watts) capable of powering large lights. And, 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. Finally, to record sync sound without picking up any generator noise, all you need to do is add 100' - 150' of heavy duty 250V twist-lock extension cable between the generator and our Full Power Transformer/Distro. This is usually enough cable to place the generator around the corner of a building, or to run it out of a van or truck - which is usually all the additional blimping you need with these generators. The heavy-duty 250V twist-lock cable eliminates multiple long cable runs to the generator and minimizes line-loss; as well as, eliminates the voltage drop you would have using standard electrical cords.

Posted Image
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.


To assure full line level (120V) on set, our 60A Full Power Transformer/Distro is designed to compensate for the slight line loss you will have over an extended cable run. That is, it is designed to slightly boost the voltage on the load side (secondary) so that if you were to feed the supply side (primary) of the transformer 240 volts from the generator, 127 volts would come out on the secondary side where you plug in the lights. This slight boost enables you to place the generator further from set where you won't hear it, yet assure that the supply voltage on set does not drop too low. Our 60A Full Power Transformer/Distro is equipped with a 60A Bates and three 20 A Edison circuits so that you have plug-in pockets conveniently on set.

Posted Image
60A GPC (Bates) Splitters and Woodhead Box.


Our new 60A Full Power Transformer/Distro offers a number of other benefits as well. Without our Transformer/Distro you can never fully utilize the full power of the generator because the load of a light has to go on one circuit/leg of the generator or the other. For example, when plugging lights into the factory installed power outlet panel of a Honda EU6500is, you quickly reach a point where you can't power an additional 1200W HMI because there is not 11.5 amps (w/ a PFC ballast) available on either one of the factory installed 20A outlets/leg of the generator. With our Full Power Transformer/Distro you can still add that 1200W HMI because the Transformer/Distro not only accesses more power (7500 Watts) through a higher rated circuit (60 Amps), but it also splits the load evenly over the two legs (5.75A/leg) of the generator. The end result is that the generator is capable of handling a larger load more easily because it is a perfectly balanced load.

Posted Image
60A Woodhead Box running Power-to-Light PFC 800W ballast (left) and PFC 1200W ballast (right.)


Another benefit to using our Transformer/Distro is that it greatly simplifies set electrics by splitting the load of what ever you plug into it automatically. This means you no longer have to carefully balance the load over the generator's two 20A/120 circuits/legs as you plug in lights because the Transfomer/Distro does it for you. With our modified Honda EU6500is you simply plug in lights until the load wattage displayed on the generator's iMonitor reaches 7500 Watts. Now that you are able to fully utilize the generator's available power, you are able to power larger lights, or more smaller lights, than you could without a transformer/distro. For more details on the use of transformers for set power, I suggest you read the article I wrote for our company newsletter (mentioned above) on the use of portable generators in motion picture production. Use this link - www.screenlightandgrip.com/html/emailnewsletter_generators.html for more information about using inverter generators with transformers for motion picture lighting.

Guy Holt, Gaffer, [url="http://www.screenlightandgrip.com""] ScreenLight & Grip [/url], Boston

Guy, Thanks for the detailed response,over the top! In short if you want to be a professional, use professional equipment, not a toy from home depot.
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#19 Lucas Griego

Lucas Griego
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Posted 02 August 2012 - 10:42 PM

Thanks for posting! Valuable info in this thread!
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