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Arri 1800w pars - anyone used them? M18?


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#1 Michael E Brown

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Posted 24 August 2010 - 11:38 PM

Have any of you guys (and gals) used one of the Arri 1800w pars yet? I'm considering a few as my market rents 1200w pars like crazy so they don't have to use generators. I think the 1800w could be popular also. Plus you can pop a 1200w lamp back in it and just use it as a 1200w fixture. The head itself doesn't cost much more than the 1200w head - it's the Arri 1800w ballast that costs a bunch more. The lamp is expensive because it's new, about double the 1200w lamp.

I'm particularly interested in the M18 lens less version. I'm curious how well this works (I've heard the 12/18K fixtures work well with the same reflector design). I'm also curious what my customers would say about not getting any lenses and being limited to a minimum 20 degree beam angle. Arri claims up to 70% more output than a 1200w - but comparing data sheets the 1800w seems closer to twice the output in most cases, which is impressive.

If you've used one - which ballast did you use? Arri's ballast is considerably more expensive than the Power Gems ballast, and Power Gems claims their ballast uses less than 17a instead of the Arri's 18a. Doesn't seem like much, but I think this could end up being a big factor with older buildings/breakers. I'm generally curious how often a customer will be able to plug in this kind of amperage draw into a wall outlet without any issues. It's close to a 2K tungsten fixture, which people plug into the wall all the time. The last thing I need is vidiots calling all the time whining that the breaker keeps tripping.
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#2 Stuart Brereton

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Posted 25 August 2010 - 10:43 AM

I'm generally curious how often a customer will be able to plug in this kind of amperage draw into a wall outlet without any issues. It's close to a 2K tungsten fixture, which people plug into the wall all the time. The last thing I need is vidiots calling all the time whining that the breaker keeps tripping.


US power outlets are rated 15amps @ 120v. That's 1800w, so you would be running the lamps right at the limit of the outlet. Remember that HMIs draw considerably more than their rated current when you strike them. The spike in current will almost certainly be enough to trip the breakers on a domestic circuit. Although people do run 2k tungstens on a domestic circuit, you can bet that outlet is getting pretty hot. It's always a good idea to leave a little headroom in terms of your draw from a wall outlet.
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#3 Michael E Brown

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Posted 25 August 2010 - 10:17 PM

US power outlets are rated 15amps @ 120v. That's 1800w, so you would be running the lamps right at the limit of the outlet. Remember that HMIs draw considerably more than their rated current when you strike them. The spike in current will almost certainly be enough to trip the breakers on a domestic circuit. Although people do run 2k tungstens on a domestic circuit, you can bet that outlet is getting pretty hot. It's always a good idea to leave a little headroom in terms of your draw from a wall outlet.


Stuart, as gaffer and rental company owner - I'm well aware of standard outlet ratings and how HMIs work. The non-ALF or non-power factor corrected 1200w ballasts already pull 16-17a which run on regular outlets all the time.

I'm more curious if the Arri ratings are accurate, real world experiences plugging the lights in, and what they look like.

Edited by Michael E Brown, 25 August 2010 - 10:18 PM.

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#4 Stuart Brereton

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Posted 25 August 2010 - 11:27 PM

Michael, it would be helpful then if you listed your occupation as Gaffer in your profile, so that you are not provided with redundant information. Also, bear in mind that you are not the only person who reads these responses, and there are many on this forum who do not share your knowledge.
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#5 Michael E Brown

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Posted 26 August 2010 - 08:07 AM

Michael, it would be helpful then if you listed your occupation as Gaffer in your profile, so that you are not provided with redundant information. Also, bear in mind that you are not the only person who reads these responses, and there are many on this forum who do not share your knowledge.



Good points. I will update my profile.
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#6 Guy Holt

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Posted 26 August 2010 - 09:25 AM

US power outlets are rated 15amps @ 120v. That's 1800w, so you would be running the lamps right at the limit of the outlet. Remember that HMIs draw considerably more than their rated current when you strike them. The spike in current will almost certainly be enough to trip the breakers on a domestic circuit.


I am afraid that Stuart is confusing two issues: the higher “Apparent Power” of Electronic HMI ballasts and the higher striking current of Magnetic HMI ballasts.

Magnetic ballasts draw more current during the striking phase and then they “settle down” and require less power to maintain the HMI Arc. For this reason you can’t load a wall circuit or a generator to full capacity with HMIs with magnetic ballasts because you must leave “head room” for their higher front end striking load. By contrast, an electronic ballast “ramps up.” That is, its’ current draw gradually builds until it “tops off.” But, unless the ballast is Power Factor Corrected (PFC), an electronic ballast will draw more current than a magnetic ballast of the same wattage. What makes the new Arri 1800W ballast so expensive is that it is Power Factor Corrected and so draws even less current than a magnetic ballast. Why ballasts of the same wattage will draw appreciably different current has to do with the Power Factor of the ballast.

Since Power Factor Correction is not mandatory in this country as it is in Europe, you will encounter many non-Power Factor Corrected HMI, Kino, CFL, & LED power supplies. And since, the adverse effects caused by a poor Power Factor go beyond an inefficient use of power, it is well worth understanding Power Factor and why it should be corrected. Besides, it explains why the Arri 1800W ballast is so much more expensive than other electronic ballasts and is worth every penny.

To understand Power Factor lets first look at a magnetic HMI ballast in more detail. Between the power input and the HMI lamp is a transformer that acts as a choke coil. The transformer provides the start-up charge for the igniter circuit, rapidly increasing the potential between the electrodes of the head’s arc gap until an electrical arc jumps the gap and ignites an electrical arc between the lamp electrodes – hence the higher striking current. The transformer then acts as a choke, reducing the current to the lamp to maintain the pulsating arc once the light is burning – hence the lower running current.

Essentially a large coil of wire that is tapped at several places to provide for various input voltages and a high start-up voltage, the transformers of magnetic HMI ballasts exhibit high self-inductance. Self-inductance is a particular form of electromagnetic induction characteristic of coils (like those in magnetic HMI ballasts) that inhibits the flow of current in the windings of the coil. This opposition to the flow of current is called inductive reactance. In the case of a magnetic HMI ballast, the multiple fine windings of the ballast transformer induces appreciable voltage and considerable current that is in opposition to the primary current, causing the primary current to lag behind voltage, a reduction of current flow, and an inefficiency in the use of power supplied to it. Put simply, the ballast draws more power than it uses to create light.

If, in the case of a magnetic ballast, you were to measure the current (using a true RMS Amp Meter) and voltage (using a Volt Meter) traveling through the cable supplying the magnetic HMI ballast and multiply them according to Ohm’s Law (W=VA) you would get the “apparent power” of the ballast. But, if you were to instead, use a wattmeter to measure the actual amount of energy being converted into real work (light) by the ballast, after the applied current overcomes the induced current, you would get the “true power” of the ballast. The ratio of “true power” to “apparent power” is a measure of the “power factor” of the ballast and is expressed by a number somewhere between 0 and 1. Where a typical 1200W magnetic HMI ballast takes 13.5 Amps at 120 Volts to generate 1200 Watts of light the power factor is .74 (13.5A x 120V= 1620W, 1200W/1620W= .74). The favorite analogy electricians like to use to explain power factor is that if apparent power is a glass of beer, power factor is the foam that prevents you from filling it up all the way. When using lights with a power factor (HMI, Kino, CFLs, & LEDS), you must size your distribution system and generator to supply the apparent power (beer plus foam.)

By comparison to magnetic HMI ballasts, electronic HMI ballasts are quite a bit more complicated. In an electronic HMI ballast, AC power is first converted into DC. Then, a high-speed switching device (micro processor controlled IGBTs) turns the flat current into an alternating square wave. Hence, they are commonly referred to as square wave ballasts. Electronic square wave ballasts utilize solid state electronic components which use only portions of the input power sine wave. Put simply, they place a disproportionately larger load on the peak values of the power waveform. These devices then return the unused portions to the power stream as harmonic currents.

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As illustrated above, these harmonic currents stack on top of one another creating harmonic distortion that likewise creates an opposition to the flow of current, pulls the voltage and current out of phase, and when the power is supplied by a generator can lead to severe distortion of the voltage waveform in the power distribution system. For example, the power waveform below left 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 severe harmonic noise exhibited here can cause overheating and failing equipment, efficiency losses, circuit breaker trips, excessive current on the neutral return, and instability of the generator's voltage and frequency. This harmonic distortion is called capacitive reactance. Since an electronic ballast also puts current and voltage out of phase with one another, it also has a power factor. An electronic square wave HMI ballast typically has a power factor less than .6, meaning the ballast has to draw 40 percent or more power than it uses. Where a typical 1200W non-power factor corrected electronic HMI ballast takes 18.5 Amps at 120 Volts to generate 1200 Watts of light the power factor is .54 (18.5A x 120V= 2220W, 1200W/2220W= .54).

When using a lighting package with low power factor (like the pkg. of non-PFC electronic HMI & Kino ballasts depicted above), the conventional wisdom in the past has been to not load the generator beyond 75% for more than a short period. Where the maximum recommend continuous load on a 6500W generator is 5500W, the de-rated continuous load rating would be roughly 4000 watts. By de-rating the load capacity in this fashion, the Gaffer minimizes the adverse effects of high THD so that both the generator and the loads placed upon it operate more reliably. However, this conventional wisdom no longer holds true if the HMI & Kino ballasts are Power Factor Corrected and powered by an inverter generator.

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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 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. What this means is that an inverter generator can be loaded to capacity with PFC HMI and Kino Flo 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 continuous load you can put on a portable gas generator (in the case of our modified Honda EU6500is generator a capacity of 7500 Watts.)

As the oscilloscope shots above illustrate, Power Factor Correction can be of tremendous benefit when operating HMIs and Kinos on portable gas generators because a PFC circuit realigns voltage and current and induces a smoother power waveform at the distribution bus. PFC circuits successfully increase the power factor to as much as .98, making ballasts with it near linear loads. As a result, the ballast uses power more efficiently with minimized return current and line noise and also reduces heat, thereby increasing their reliability. A typical 1200W power factor corrected electronic HMI ballast takes 11 Amps at 120 Volts to generate 1200 Watts of light the power factor is .91 (11A x 120V= 1320W, 1200W/1380W= .91).

Power Factor Correction makes the newest electronic ballasts, like the Arri 1800W ballasts, worth the extra money when it comes to lighting with portable generators. Where before you could not operate more than a couple 1200W HMIs with non-PFC electronic 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 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.

If you haven't already, I would suggest you read the article I wrote for our company newsletter on the use of portable generators in motion picture lighting. In it I cover some of the basic electrical engineering principles behind poor Power Factor, the harmonic distortion it can generate, and how it can adversely affect generators. These power generation issues have been vexing set electricians for years. Use this link for an informative newsletter article that explains the electrical engineering principles behind these issues and how to resolve them.

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This article is cited in the just released 4th Edition of Harry Box's "Set Lighting Technician's Handbook" and featured on the companion website "Box Book Extras." Of the article Harry Box exclaims:

"Great work!... this is the kind of thing I think very few technician's ever get to see, and as a result many people have absolutely no idea why things stop working."


"Following the prescriptions contained in this article enables the operation of bigger lights, or more smaller lights, on portable generators than has ever been possible before."


The article is available online at http://www.screenlig...generators.html.

Guy Holt, Gaffer, ScreenLight & Grip, Lightng & Grip Rental in Boston
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#7 Josh Fritts

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Posted 27 August 2010 - 12:35 AM

I used them last week and was very impressed. They are considerably more powerful than 1200w pars. I was shooting a commercial in a indoor skate park that had large overhead sky lights and they had plenty of stop after being shaped up pretty heavily. I would almost compare them to 4k pars. When you think about it, once you put a lens in front of a 4k par, the amount of light that the glass eats will bring the light down into the world of the 1800s.


Its a little vague, but hopefully this helps
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#8 Michael E Brown

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Posted 27 August 2010 - 09:29 PM

I used them last week and was very impressed. They are considerably more powerful than 1200w pars. I was shooting a commercial in a indoor skate park that had large overhead sky lights and they had plenty of stop after being shaped up pretty heavily. I would almost compare them to 4k pars. When you think about it, once you put a lens in front of a 4k par, the amount of light that the glass eats will bring the light down into the world of the 1800s.


Its a little vague, but hopefully this helps


Thanks for the feedback. Arri says 70% brighter in all their literature, but a comparison of photometric data shows pretty much double the output of a 1200w all around.

Did you tie in power or did you plug them into some house circuits in the skate park? Did you use the M18 lensless fixture or the AS18? Your comparison seems to indicate the lensless model, just wanted to clarify.

I'm a bit concerned that the 20 degrees of the M18 would not be narrow enough for some uses. The conversion kit to AS18 is only $300ish (no lenses).
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#9 Josh Fritts

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Posted 28 August 2010 - 10:26 AM

Thanks for the feedback. Arri says 70% brighter in all their literature, but a comparison of photometric data shows pretty much double the output of a 1200w all around.

Did you tie in power or did you plug them into some house circuits in the skate park? Did you use the M18 lensless fixture or the AS18? Your comparison seems to indicate the lensless model, just wanted to clarify.

I'm a bit concerned that the 20 degrees of the M18 would not be narrow enough for some uses. The conversion kit to AS18 is only $300ish (no lenses).



We did have a tie in, so I'm not to sure how they would handle on regular household circuits and I'm not to sure how the electric department was handling their distro.

We were using the lensless fixtures. I don't remember ever having too much problem with spread. That being said, I almost alway start the light through a 4x4 frame of something and then either through another larger diffusion or into a bounce.

The quality that stood out the most was definitely the light output. It was extremely powerful.
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#10 timHealy

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Posted 31 August 2010 - 08:30 PM

A friend has been raving about them. Used them instead of 4k's. Don't recall if they had a tie in, generator, or wall outlet.

I look forward to using them.

Tim
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#11 Michael E Brown

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Posted 31 August 2010 - 08:39 PM

Couple other people I talked to said they were great, and lots of great reviews of the lensless M18 also.

Apparently they are selling well also, Arri says they won't have any for 5 weeks.
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#12 Albert Smith

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Posted 02 September 2010 - 11:18 PM

US power outlets are rated 15amps @ 120v. That's 1800w, so you would be running the lamps right at the limit of the outlet. Remember that HMIs draw considerably more than their rated current when you strike them. The spike in current will almost certainly be enough to trip the breakers on a domestic circuit. Although people do run 2k tungstens on a domestic circuit, you can bet that outlet is getting pretty hot. It's always a good idea to leave a little headroom in terms of your draw from a wall outlet.




although a lot of old buildings are all 15amp alot of boxes are full of 20's now especially in places like kitchens.


these lights are without a doubt designed to run on household.....why else make a 1800W light.
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#13 Michael E Brown

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Posted 06 September 2010 - 12:27 PM

although a lot of old buildings are all 15amp alot of boxes are full of 20's now especially in places like kitchens.


these lights are without a doubt designed to run on household.....why else make a 1800W light.


Stuart's point was not about the breakers - he specifically mentioned the actual outlet.

As you said, most breakers are 20a now but with 15a receptacles as the NEC allows over rating the breakers for circuits with multiple receptacles. Only in commercial buildings (and maybe garage/shop areas) will you see 20a receptacles.

Each outlet on a duplex receptacle can supply the full rated current. In the case of a 15a receptacle, if you needed to plug in 16a - you could plug 12a into the bottom outlet and 4a into the top outlet and stay under the 15a rating while taking advantage of the 20a circuit breaker.

However, I have found there to be no difference between quality 15a/20a hardware except for the ability to accept/reject 20a turned blade plugs. 15a and 20a Hubbells are identical except the direction of the blades. Same goes for Hubbell outlets. The original reason for creating a difference in these plugs probably came about before this standard. Manufacturers were trying to keep you from plugging in a 20a plug into a 15a outlet - which at the time, also had a 15a breaker.

Now, this probably does not hold true for the $.35 cheapo outlets at Home Depot. I wouldn't plug 15a into any of those.
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#14 Guy Holt

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Posted 12 November 2010 - 10:47 AM

I would almost compare them to 4k pars. When you think about it, once you put a lens in front of a 4k par, the amount of light that the glass eats will bring the light down into the world of the 1800s. Its a little vague, but hopefully this helps


There is a lot of hyperbole like this flying around regarding the output of the new Arri M18 "Baby Max." As a Gaffer, Rental House, and Arri dealer I have had the opportunity to work extensively with these heads. While it is difficult to compare a Par, Fresnel, and a Baby Max because they are such different lights, to shed some light on this debate I undertook tests using a common denominator and here is what I found.

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Comparison between 2.5 Par w/ 20 deg. Med Lens (left), 1800 Baby Max in 20 deg. Spot (Center), and 1800W Par w/ 20 deg. Med Lens (Rght)



A med lens in a 2.5 Par is about equivalent to the wide angle of the Baby Max - 20 degrees. So I took photometric measurements of those two (see fist table below.) Where there is no easy way to find the 20 degree point on the spot/flood of a 4k Fresnel, what I did is find the point on the 4k Fresnel spot/flood where the beam diameter to 50 percent drop off was the same as on the Baby Max and took measurements there (see 2nd table below.)

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What I found was that 1800W Baby Max has a comparable output to a 2.5kw Par and 4k Fresnel, but with a light distribution and quality closer to a Fresnel than a Par. For instance, if you were to spot down the Arri 1800W Baby-Max to the same beam diameter as the 2.5kw Par with Medium Lens in the photometric table above, it would achieve an output comparable to that of the 2.5k Par. But, as is evident in the picture above and the photometric table below, the light distribution is more similar to that of a 4k Fresnel.

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What accounts for the even light distribution is the Baby Max’s unique reflector which creates diverging rays to produce a crisp shadow from an open face fixture. And, since there is no light lost to a lens, the Baby Max has considerably more output than that of a par – but not nearly the output of a 4k Par.

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Still, to have the output of a 2.5kw Par with the light quality of a Fresnel from an instrument that you can operate on a 20A circuit* is impressive. With a beam angle of 20 to 60 degrees, the Baby Max doesn’t have the long throw of a par with narrow lens, but then how often do you use a narrow lens. Most of the time I find I am using the wide or super wide lens and in that regard the wide of the Baby Max is considerably wider a field angle than the widest par lens (60 degrees vs. 40 degrees.)

While definitely not a substitute for a 4k par, the Baby Max’s unique reflector design enables it to achieve an output comparable to that of a 2.5kw Par, but with a light quality and spread comparable to a 4k Fresnel.

Guy Holt, Gaffer, ScreenLight & Grip, Lightng & Grip Rental in Boston

* There is also a lot of hyperbole flying around regarding plugging 1800w Baby Maxs into wall outlets. But, I will have to address that issue in a later post.
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#15 Guy Holt

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Posted 13 November 2010 - 05:50 PM

...these lights are without a doubt designed to run on household.....why else make a 1800W light.


I am afraid that Arri is engaging in a bit of hyperbole when they claim the Baby Max is “the brightest light that you can plug into the wall.” Lately, they have been footnoting that claim as follows: ““Into the wall” denotes a single, 20A 120VAC electrical outlet on a single circuit.” The reason for the footnote is that, as discussed above, many wall outlets are on 15 Amp circuits, and those that are on 20 Amp circuits probably use receptacles only rated for 15 Amps. This is a problem because the Arri 1800W ballast has an Apparent Power of 2250VA which means that it will draw 19.5 amps at 115V so it will always trip the common 15amp house circuit and will trip a 20 Amp circuit if there is something else, like a computer or light, on the same circuit. Where you can't always know what else is on the same circuit, or even if it is a 20 or 15 Amp circuit, it is risky to plug the Baby Max into the wall. Especially since the house odds are stacked against you.

The problem is that the draw of the 1800W Baby Max – 19.5A at 115V – is just too close to the threshold to operate reliably. If there is any line loss from a long cable run, or increased resistance from an overheated plug end, the draw of the ballast climbs over 20 Amps and trips the breaker. It has been my and other Gaffer’s experience that the stinger plug-ends overheat because most are only rated for 15 Amps. The increased resistance that results from the heat causes the voltage to the ballast to drop and so it has to draw more power to maintain the 1800W load. At 110V it will draw 20.5 Amps. In my experience the power drawn by the 1800W Baby Max is just too near the operating threshold of a 20A circuit for it to operate reliably plugged into a U-Ground Edison Outlet.

The same is true of operating them on the 20A circuits of portable generators. Even though the generator’s Edison receptacles are rated for 20Amps and the generator has two 20A circuits, it has been my experience that you can not run a 1800W Baby Max reliably on the 20A receptacles on the generator’s power panel. To the problem of line loss and overheating plug ends, you have the added problem that as you add load the voltage drops on portable generators. It is not uncommon for a generator to drop 10-15 volts under full load. The 1800W ballast that drew 19.5 Amps at 115 Volts will draw 21.4 Amps at 105 Volts.

As the other posters here have attested, the Arri 1800W Baby Max works best on a real film distribution system where every circuit is 20 Amps, you know what is on the circuit because you are loading it yourself, and you are bringing the receptacle to the light because you are distributing the power yourself from a tie in or generator. When you can run a 100A whip and drop a Lunch Box next to the ballast you won’t have a problem. But, if your style of shooting requires that you run multiple stingers to plug into a wall or generator outlet, you will likely have problems with the plug ends or receptacle overheating and causing the breaker to overheat and trip.

I have found that the only reliable way to power a 1800W Baby Max on wall out-lets or on portable gas generators is from a 240V circuit through a 240v-to-120v step down transformer. A transformer will convert the 240V output into a single large 120V circuit that is more than capable of powering the 19.5A load of a 1800W Baby Max. And, if the transformer is outfitted with a 60A Bates receptacle, it will enable you to use a distro system that will allow you to move the generator off set (where it won’t be heard), minimize line loss over a long cable run, and provide plug-in pockets conveniently close to the ballasts.

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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 record sync sound without picking up any generator noise, all you need to do is add 200' of heavy gauge 250V twist-lock extension cable between the generator and the transformer. 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 the Honda EU generators. By using a single heavy-gauge feeder cable, you eliminate multiple long cable runs to the generator and the appreciable voltage drop you would have using standard electrical cords. Unlike 15 Amp U-Ground Edison plugs, the 30A/250V twist-lock plug ends won’t overheat and so won’t add resistance and won’t cause additional voltage drop that will cause the ballast to draw more power and trip the breaker.


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60A GPC (Bates) Splitters and Woodhead Box.


To assure full line level (120V) on set, use a "boost transformer" like ours that is designed to compensate for the slight line loss you will inevitably have over an extended cable run. If you were plug it directly into the generator and feed the supply side (primary) of the transformer 240 volts, a "boost transformer" will give you 127 volts on the secondary side where you plug in your lights. This slight boost enables you to run 200’ or more of cable to get the generator further from set where you won't hear it, yet assure that the supply voltage on set does not drop below 120V and cause the 1800W ballast to draw more power and trip its’ 20A breaker. If the transformer is like ours and equipped with a 60A Bates you can use standard film distribution equipment like 60A Siameses, 60A Whips, and 60A Snack Boxes to run power to the light (breaking out to 20A Edison pockets next to the ballast), rather than having to run multiple stingers from the ballast back to the generator.

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


If you want to be extra cautious, you can swap the Edison plug end on the ballast for a 60A Bates that won’t overheat under any circumstances. In our shop, when we lamp the M18 Baby Max head with the 1800W globe for a student production, we use a 60A Bates plug on the ballast. We do this in order to eliminate the possibility that an inexperienced student “electrician” will run multiple stingers to the ballast which is a recipe for disaster. Since we started doing this the number of late night emergency calls has dropped to zero. We use the 60A Bates simply because it is the next size up connector that is standard in distro systems. You could use a 30A/120V twist-lock connector when operating them on a generator, but 30A Twist isn’t very common in film distros, so you will have to run multiple ones all the way back to the genny, and where there is only one 30A receptacle on most portable genertors, you are limited to powering only one 1800W Baby Max. By contrast, if the generator is one of our modified Honda EU6500is generators, a transformer will convert the enhanced 7500W output of the generator into a single 60A/120V circuit that is capable of powering up to three 1800W Baby Maxs. And where the 1800W Baby Max has an output comparable to a 4k that is a lot of fire power on a portable generator.

A transformer will also enable you to run 1800W Arri Baby Maxs on “house power” from common 240v household outlets as well. Just like it does with a generator, a transformer will step down the 240V power of common high voltage household outlets to a single 120V circuit capable of powering multiple 1800W Baby Maxs. Common 240V sources found on interior locations include Range Plugs, Dryer Plugs, and special receptacles installed for Window Air Conditioners. By giving you access to more “house power” through common 240V household outlets, a transformer also enables you to run a real distro system without the need for a dangerous tie-in or expensive tow generator. The ability to run multiple 1800W Baby Maxs off of common 240V house receptacles, or the 240V receptacle of portable generators, is one of the best reasons that I can think of to use transformers on set.

For more detailed information on using transformers on set, I would suggest you read an article I wrote on the use of portable generators in motion picture production. Harry Box, author of “The Set Lighting Technician’s Handbook” has cited my article in the just released Fourth Edition of the handbook. In addition, he has established a link to it from the companion website for the Fourth Edition of the Handbook, called “Box Book Extras.”

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If you haven't yet read the article, or looked at it in a while, it is worth reading. I have greatly expanded it to be the definitive resource on portable power generation for motion picture production. Of the article Harry Box states:

"Great work!... this is the kind of thing I think very few technician's ever get to see, and as a result many people have absolutely no idea why things stop working."

"Following the prescriptions contained in this article enables the operation of bigger lights, or more smaller lights, on portable generators than has ever been possible before."



The “Box Book Extras,” site is also worth checking out because it includes other source material used for the handbook, articles by Harry Box published in other periodicals, related websites, a list of production oriented i-phone apps, as well as more in depth discussion of topics touched upon in the handbook. You can log onto the Box Book Extras site at http://booksite.focalpress.com/box/setlighting/ with our pass-code "setlighting." Use this link for my news letter article on the use of portable gas generators in motion picture production.

Guy Holt, Gaffer, SceenLight & Grip, Lighting and Grip Rental in Boston.
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