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Used HMI Light. Good investment?


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Hi I have been debating about buying a used HMI light for my small grip truck. Right now I have bunch of aputure led lights, Qusar tubes and Tungsten lights. I am based in Los Angeles and can rent them for 100-250 a day. 

But does any one have thoughts if this is a good deal and worthy investment. https://www.usedlighting.com/19692/arri-arrisun-1200w-plus-hmi-par-kit?ref=products.categories

Arri Arrisun 1200W Plus HMI Par Kit for $2700 after shipping and tax. They do not say how old or how much they have been used. But offer 180 day warranty. 

My concern is how long will it last before it needs to be repaired and is it crazy expensive to get HMI repaired in Los Angeles? What are you're thoughts? Are these like a 90s Toyota engines that just keep going and going or will it be every time before I strike it I'll need to make a animal sacrifice to the lighting gods to get it to work?   

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I’d buy a used HMI. I’ve purchased one before. All it needs is a new bulb and sometimes if they come with a old ballast (magnetic) I buy it a new electronic one. 

However I’ve purchased only one 1.2 HMI par Arrisun in the past second hand. It was for 1300 AUD. About 850 USD on eBay. Now some could say ‘risk factor’. Which there is. However if your buying a second hand Arri HMI and want a quicker return on investment I’d find a better deal. Also the factor of ‘do you need it’. A 1.2k is a great light. However it sounds like you already have a pretty strong package if your buying a HMI to let’s say punch through a window. I’d buy something bigger than a 1.2k. 

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Pretty bullet proof though.

I can't see the head feeder connectors but if it is a new one made by LEX that are molded type connectors,  plan on a repair for that and don't repair it with the same style connector.
Contact Galaxy HMI repair and have them put on the metal connectors.

Guaranteed to fail.

IMG_3536.JPG

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Bear in mind that doing what's been suggested above, buying a new ballast for it, is likely to be a tremendously expensive operation in its own right. The one that's there looks like a reasonably early generation electronic ballast, but you definitely don't want a magnetic one.

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On 2/9/2020 at 8:06 PM, Alexander Sutton Hough said:

Hi I have been debating about buying a used HMI light for my small grip truck....does any one have thoughts if this is a good deal and worthy investment. https://www.usedlighting.com/19692/arri-arrisun-1200w-plus-hmi-par-kit?ref=products.categories

Given the evolution of HMI technology over the years you can easily get stuck with a lemon if you are not careful. The history of HMI ballast design can be characterized as the proverbial two steps forward while making one step back.  When electronic square wave HMI ballasts came on the market, they were at first thought to be the solution to all the problems inherent in running HMIs with magnetic ballasts on portable generators. Since they are not frequency dependent, it was thought at first that electronic square wave ballasts would operate HMIs more reliably on generators – even those without frequency governors. By eliminating the flicker problem associated with magnetic ballasts, they also eliminated the need for the expensive AC governors required for flicker free filming with magnetic HMI ballasts and portable generators.

For these reasons, as soon as electronic square wave ballasts appeared on the market, many lighting rental houses replaced the expensive crystal governed Honda EX5500 with the less expensive non-synchronous Honda ES6500. The theory was that an electronic square wave ballast would operate reliably on a non-governed generator and allow filming at any frame rate, where as a magnetic HMI ballast operating on an AC governed generator allowed filming only at permitted frame rates. In practice, electronic square wave ballasts turned out to be a mixed blessing. The leading power factor caused by the capacitive reactance of the then new electronic ballasts proved to have a more severe effect on conventional AVR generators than did the old magnetic ballasts. In response lighting manufacturers introduced a second generation of electronic ballasts that incorporated power factor correction. But, Power Factor Correction (PFC) is not mandated in this country, as it is in Europe for any electrical device that draws more than 75W., and so in this country most HMI ballasts smaller than 6kW continued not to be power factor corrected.

The early line of Lightmaker electronic ballasts were nick named by film electricians “Troublemaker” ballasts because they were not Power Factor Corrected and proved that PFC circuitry was absolutely necessary in large ballasts to reduce heat and returns on the neutral, and to increase ballast reliability (beware, some are still kicking around ebay). But, because of the added cost, weight, and complexity of PFC circuitry, ballast manufacturers in the US only offered PFC circuitry as an option in medium-sized 2.5-4kw ballasts. And, until fairly  recently manufacturers did not offer PFC circuitry in HMI ballasts smaller than 2.5kw in the US (in the EU PFC circuitry in mandatory in all HMI ballasts sold.) Part of the reason was that PFC circuitry did not offer a huge advantage when plugging into house power. A typical 1200W Power Factor Corrected electronic HMI ballast will draw 11 Amps at 120 Volts verses the 19 Amp draw of a non-PFC electronic ballast. While not a huge advantage when plugging into house power, the added efficiency of a PFC 1200 ballast can make a huge difference when powering a lighting package off of a small portable generator or when using GFCIs.  For example, when you consider what LEDs draw, the 8 Amp difference between using a PFC 1200W electronic ballast and standard non-PFC 1200W electronic ballast, can mean the difference between running a lot more lights on a portable generator or not – I think you would have to agree that is a major boost in production capability. 

A second drawback to non-pfc ballasts is that the harmonic distortion they create  reacts poorly with the distorted power waveform of conventional AVR generators, which severely  limits the number of them you can power on a portable generator. The adverse effects of this harmonic noise, can take the form of overheating and failing equipment, efficiency losses, circuit breaker trips, excessive current on the neutral wire, and instability of the generator’s voltage and frequency. For these reasons it has never been possible to operate more than a couple of non-pfc 1200W HMIs on a conventional 6500W portable gas generator. Harmonic noise of this magnitude can also damage HD digital cinema production equipment, create ground loops, and possibly create radio frequency (RF) interference. The increasing use of personal computers, hard drives, and microprocessor-controlled recording equipment in production has created an unprecedented demand for clean, reliable power on set. Unfortunately, it is the case that almost every 575 - 1200 W electronic ballast that you will find for sale used in North America will be a non-PFC electronic ballast.

While older HMIs with non-pic ballasts are less expensive, Power Factor Correction (PFC) makes the newest electronic ballasts worth the extra money when it comes to lighting with portable generators. The substantial reduction in line noise that results from using power factor corrected ballasts on the nearly pure power waveform of an inverter generator creates a new math when it comes to calculating the load you can put on a generator. In the past we had to de-rate portable gas generators because of the inherent short comings of conventional generators with AVR and Frequency governing systems when dealing with non-PFC electronic ballasts. The harmonic distortion created by non-PFC ballasts reacting poorly with the distorted power waveform of conventional AVR generators limited the number of HMIs you could power on a portable generator to 75% of their rated capacity (4200Watts on a 6500W Generator). But now, where inverter generators have virtually no inherent harmonic distortion or sub-transient impedance and power factor correction (PFC) is available in small HMI ballasts, this conventional wisdom regarding portable gas generators no longer holds true. Where before you could not operate more than a couple 1200W HMIs with non-PFC 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 LED ballasts are Power Factor Corrected (a lot of LED ballasts are not.) 

For more detailed information on HMIs I would suggest you read an article I wrote for our company newsletter on operating HMIs on portable generators. This article is cited in the 4th Edition of Harry Box's "Set Lighting Technician's Handbook" and featured on the companion website. 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.screenlightandgrip.com/html/emailnewsletter_generators.html.

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

 


 

 

 

 

 

 

 

 

Guy Holt, Gaffer, 

ScreenLight & Grip 

Lighting Rental & Sales in Boston

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