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How safe is this? HMI and 6500 generator


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#1 Jason Anderson

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Posted 13 February 2008 - 03:40 PM

I have a 6500 watt generator and will be plugging in a 4k hmi and a 800 hmi and perhaps some additional lights, How close do you think I am able to get to the ceiling of this generator before I have problems.

Do the HMI's have a spike in wattage when they first start up?
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#2 Adrian Sierkowski

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Posted 13 February 2008 - 03:42 PM

They have a spike a voltage, and also you might be overloading the circuits for the genny, If it's a 6500W genny from Honda I think it onyl have 20A breakers, so a 4K HMI will overload it. Alos, I'm not 100% sure, but I think for HMIs you need a crystal governor in order to run an HMI
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#3 Jason Anderson

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Posted 13 February 2008 - 03:57 PM

It is a crystal sync genny, and it is supposed to have a 60 amp plug on it according to the rental house. I am not certain if it is made by Honda or not.

Thanks for the reply
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#4 Adrian Sierkowski

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Posted 13 February 2008 - 04:23 PM

60A and synced you should be totally fine.
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#5 Matthew Parnell

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Posted 13 February 2008 - 07:46 PM

6500w x 0.85 (safeish power factor for an unknown genie) = 5525w max constant draw.

So a 4k and a 800w = 4800w. So you have headroom to add about 700w of extra lamps, BUT I would also suggest turning the 4k on first then the 800w then adding more load after that. The HMI's have huge voltage spikes when striking.
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#6 Mathew Rudenberg

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Posted 13 February 2008 - 09:15 PM

Also, beware that HMI's don't behave like regular tungsten lights in terms of amperage - a 1k will always pull 8.3A at 120V (not considering line loss etc.), but depending on the ballast a 1200 can pull between 16 and 20A - so you may end up closer to the limit than you think.

Actually I always wondered why they call it a 1200w if it pulls 17 amps (powergems ballast)... shouldn't it be called a 2K? (or a 2040w)

Anyway, your '4k' could actually be eating 50 or more amps... look at the ballast.
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#7 Walter Graff

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Posted 13 February 2008 - 10:35 PM

Wow there is a lot of misinformation in this post!

You can use a 4k on a 6500 genny without a problem using the 4 pin twist lock 220 volt connector. Use the electronic ballast. I've done it numerous times. Problem is you can't run more than the 4k and then the genny must be in good working condition. Newer gennys are more reliable. Older ones can make a slight flicker. I would make sure to test it at the rental house to make sure the genny is working properly under load. Rental house often don't do much maintance on gennys and unless there is a problem they jsut refill it.

Yes HMIs spike in current draw to start then the draw drops considerably once the lamp balances.
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#8 Sean Conaty

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Posted 14 February 2008 - 01:46 AM

Hold the Phones!

The Honda 6500 generator is not a 65 Amp generator, as one would guess. I made this mistake in plotting out an equipment package and was fortunately told that the genny was rated at around 45 amps. In other words, the number following the generator is not the wattage. I may be totally mistaken and have played it safe as a result, but I would double check it with the rental house before trying to plug in a 4k and an 800 (especially because of the initial power draw necessary to strike an HMI).

-sean
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#9 Adrian Sierkowski

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Posted 14 February 2008 - 01:49 AM

I don't think it's a Honda 6500W genny. The ones of those I've seen here in Philadelphia aren't crystal governed and his rental house is saying this one is.
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#10 JD Hartman

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Posted 14 February 2008 - 12:22 PM

Hold the Phones!

The Honda 6500 generator is not a 65 Amp generator, as one would guess. I made this mistake in plotting out an equipment package and was fortunately told that the genny was rated at around 45 amps. In other words, the number following the generator is not the wattage. -sean


Not true, the model number represents the peak watts the alternator will deliver for a brief time before overheating. Honda and other mis-represent their generators by stating the peak instead of the continuous output. The same holds true for the Honda EU 2000 and 3000, they will not deliver 2kw and 3kw continuously.

The only small generator manufacturer I know of that doesn't do this is ONAN.
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#11 Sean Conaty

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Posted 14 February 2008 - 01:00 PM

Not true, the model number represents the peak watts the alternator will deliver for a brief time before overheating. Honda and other mis-represent their generators by stating the peak instead of the continuous output. The same holds true for the Honda EU 2000 and 3000, they will not deliver 2kw and 3kw continuously.

The only small generator manufacturer I know of that doesn't do this is ONAN.


good to know.
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#12 Walter Graff

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Posted 14 February 2008 - 01:08 PM

Hondas EB6500 genny works with a 4k electronic ballast. We use them all the time although I prefer two 2k HMIs in case of trouble. A generator is always rates in watts. 6500 means it can produce a max of 6500 watts. Amps are not watts. This generator produces a max of 54.2 amps at 120 or half that for both legs of 220. Generators are always rated at maximum wattage. But it is always a good idea to give yourself headroom with a genny because new out of the box they work great but over time do not work at 100% capacity. HMI have a strike current and a draw current once the ballast is equalized. Obviously the strike curent is the greatest and the draw curent usually a third of that. The 6500 gives you enough to strike a 4k while hte 55oowatt does not. While this set up works you must make sure the genny is in good shape. Here is an example where we used 2 2.5ks with the Honda genny.

Wait till the middle to end when they are playing at night with NYC in the background and we are using a nightvision lens:

http://tinyurl.com/2dg8jy
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#13 Guy Holt

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Posted 14 May 2009 - 06:16 PM

Wow there is a lot of misinformation in this post!


I run a rental house in Boston by the name of ScreenLight and Grip and we rent and sell small portable generators for film production. The conventional wisdom regarding portable generators reflected in these posts went out the window with the recent development of inverter generators and power factor correction (PFC) in smaller (575-1200W) HMI ballasts. It is now possible to get 7500W of clean stable power in a single 120V circuit from a portable generator. And, when you add up the incremental savings in power to be gained by using PFC HMI ballasts, add to it the energy efficiency of light sources like LEDs and Kino Flos, and combine it with the increased light sensitivity of film stocks and digital imaging systems, you have what, I would argue, amounts to a paradigm shift in lighting with portable generators.

In the past, it was not possible to reliably operate more than a couple of 1200w HMIs on a portable generator. 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 adverse effects of the harmonic distortion generated by HMI ballasts (see power waveform below left), can take the form of overheating and failing production equipment, circuit breaker trips, overheating of the neutral wire, and instability of the generator voltage and frequency. Severe harmonic noise can also damage HD digital cinema production equipment, create ground loops, and create radio frequency (RF) interference.


www.screenlightandgrip.com/images/waveform_AVR-Inv_Pkg.jpg

If one knows how, it is possible to take advantage of recent technological advances in HMI ballast design and power generation, to create clean stable set power (like that in the power waveform above right) that is capable of reliably operating larger lights (HMIs up to 6kw or Quartz lights up to 5kw), or more smaller lights, off of portable gas generators than has ever been possible before.

For example, on a recent independent short shot on the Red, I used a modified Honda EU6500is Generator to power a lighting package that consisted of a 2.5kw, 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 the Red Camera, this was all the light we needed to light a large night exterior.

But, given the wide variety of generators manufactured, it is important to understand the benefits and drawbacks to each when it comes to their use in motion picture production. Especially, given that the increasing use of personal computers and microprocessor-controlled recording equipment in HD production has created an unprecedented demand for clean, reliable power on set at a time when the trend in lighting is toward light sources that can generate dirty power. For this reason, I have tried to compile a comprehensive survey of the prevalent lighting and portable power generation equipment. Test how well they work together and make the results available to the production community. Where Harry Box, the author of the Set Lighting Technician’s Handbook is interested in incorporating this material in the 4th edition of the handbook I am making it available for peer review first.

I feel the need to make this material available prior to publication in the handbook because specific details of the inner workings of the latest portable power generation equipment is in short supply and harmonic noise has only recently become an issue. Why is harmonic distortion suddenly an issue in motion picture production? Because, the power generation and electrical distribution systems developed for motion picture production were never designed to deal with the abundance of non-linear loads like the electronic HMI and Fluorescent lighting ballasts so prevalent in production today. It’s a problem that has only recently begun because of the increasing use of these types of non-linear lighting loads. 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 are themselves sources of harmonic distortion.


In the past, attention was given to generator features such as automatic voltage regulation and speed regulation. But, given the rise in production problems associated with harmonic noise, an increasingly more important feature today is the quality of the generated power waveform and how well it interacts with today's light sources. For that reason, I did a series of tests that have resulted in oscilloscope shots of the power waveforms of different light sources on different portable generators. I have attempted to interpreted the artifacts of harmonic distortion exhibited in these power waveforms, but where this is a relatively new issue, I welcome the input of other film/video production professionals so that the material can be as complete as possible for the handbook.

To see the results of my tests, use the link below to our website where I have posted my analysis of the compatibility of the latest lighting and portable power generation technology

www.screenlightandgrip.com/html/emailnewsletter_generators.html

I welcome any and all feed back.

- Guy Holt, Gaffer, ScreenLight & Grip, Boston
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