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Using HMI with a regular generator? Questions

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#1 Roger Alexander

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Posted 22 May 2018 - 11:37 AM

I read online that you can ONLY use HMI lights with inverter generators.

 

Question 1:  What would happen if I tried to power an M18 with a generator that was not inverter? It's just a regular gas genny. Would that damage the light or ballast? Would it just not work?

 

Questions 2: I have a Ryobi 1800w running watt, 2300 starting watt generator seen here: I'm told that hmi's require a higher wattage when striking. Would I be able to strike an m18 with this Ryobi generator? Is 2300 enough to strike it? What's the wattage required to strike?

 

Question 3: If I tried to strike the m18 on that ryobi genny and it was not enough power, what would happen? Would the light just not turn on? Is there any risk of damaging the light when you try to strike it and there is not sufficient power?


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#2 Guy Holt

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Posted 22 May 2018 - 12:45 PM

I read online that you can ONLY use HMI lights with inverter generators.

 

Question 1:  What would happen if I tried to power an M18 with a generator that was not inverter? It's just a regular gas genny. Would that damage the light or ballast? Would it just not work?

 

Questions 2: I have a Ryobi 1800w running watt, 2300 starting watt generator seen here: I'm told that hmi's require a higher wattage when striking. Would I be able to strike an m18 with this Ryobi generator? Is 2300 enough to strike it? What's the wattage required to strike?

 

Question 3: If I tried to strike the m18 on that ryobi genny and it was not enough power, what would happen? Would the light just not turn on? Is there any risk of damaging the light when you try to strike it and there is not sufficient power?

 

There is a lot of misinformation on the web about running HMIs on generators because it is a complicated subject. It matters not only what type of generator you use but also what type of ballasts your lights use. The harmonic noise that magnetic and non-PFC electronic ballasts (both HMI & Kino) kick back into the power stream can have a severe adverse effect on the power waveform of conventional AVR generators like yours. The harmonic noise these light sources generate will not have nearly as bad an effect on the power supplied by an inverter generator. But, since the M18 ballast is power factor corrected it will not effect the power quality of either types of generators.  You also don’t have to worry about the ballast drawing a lot of current when it strikes.  Magnetic ballasts strike high and then settle down.  Electronic ballasts like the one the M18 uses strikes low and then ramps up to its’ full load. But, since the 1800W rating for your generator is for a continuous load, and the 1800W M18 will operate continuously, you are right on the threshold of the generator’s capacity so there is no telling if it will work until you try.  The worst that will happen is that the ballast will shut down from under voltage.

 

For more details on what type of generator to use with HMIs and fluorescent lights read the article I wrote for our company news letter on the use of portable generators in motion picture production.

 

BoxBook.jpg

 

This article is cited in the 4th Edition of Harry Box's "Set Lighting Technician's Handbook." 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, Lighting Rental & Sales in Boston


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#3 Roger Alexander

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Posted 06 August 2018 - 12:06 AM

Thank you for your answer. So just to be 100% clear, I CAN power my m18 off of a regular, non-inverter generator, and still operate safely without damaging the light, correct?


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Willys Widgets

Media Blackout - Custom Cables and AKS

FJS International, LLC

New Pro Video - New and Used Equipment

Ritter Battery

Aerial Filmworks

rebotnix Technologies

Abel Cine

Metropolis Post

Broadcast Solutions Inc

Rig Wheels Passport

CineTape

CineLab

Wooden Camera

Technodolly

Gamma Ray Digital Inc

Paralinx LLC

Visual Products

Glidecam

Tai Audio