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Using cheap generators with an HMI


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#1 Tim Tyler

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Posted 11 May 2005 - 08:38 PM

Anybody have any advice about using a < $500 portable generator with a magnetic ballast HMI?

Is there a risk of ruining the ballast, unit, or globe with that quality of A/C?
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#2 David Mullen ASC

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Posted 11 May 2005 - 09:17 PM

Anybody have any advice about using a < $500 portable generator with a magnetic ballast HMI?

Is there a risk of ruining the ballast, unit, or globe with that quality of A/C?

<{POST_SNAPBACK}>


No, the only risk is that you might get HMI flicker or that the light might not strike -- I once tried to use a 2500 watt HMI PAR in a small put-put gennie that seemed to have enough amps but it wouldn't strike. The 1200 watt did.
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#3 timHealy

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Posted 11 May 2005 - 09:18 PM

Anybody have any advice about using a < $500 portable generator with a magnetic ballast HMI?

Is there a risk of ruining the ballast, unit, or globe with that quality of A/C?

<{POST_SNAPBACK}>



Is it crystal synced with a Barbra Coleman or similiar technology?

if no, don't use it unless you like HMI flicker.

If yes, than as long as the light doesn't draw more than 75% or so of the amperage rating. You should be good to go without damaging the light.

I would be interested to know if anyone got away with using a non crystal sync generator and an electronic flicker free ballast??


Tim

PS Honda makes great and quiet generators.
http://www.hondapowe...delName=eu2000i
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#4 Paul Marschall

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Posted 11 May 2005 - 10:19 PM

I ran a 4K Par with electronic ballast off a 6500watt put-put. I haven't seen the footage myself, but I'm told it's fine.

I wouldn't do this regularly, it was out of neccessity.
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#5 Dominik Muench

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Posted 11 May 2005 - 11:29 PM

i can only second what dave said, with those cheap generators you can never be sure if they run 100% on 50herz or whatever the current is, a friend of mine got pretty bad hmi flicker when he used a normal construction site generator.
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#6 Bob Hayes

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Posted 12 May 2005 - 01:24 AM

Hello from Bangkok.

I am about to do just that. So I would love to get some info. 2 1.2 on a 5500 no crystal gennie.

In South Africa I did just this but I was shooting 25fps. This gives you a larger window. Also my gaffer installed an inline sync meter and constantly adjusted the gennie to 50 cycles. No flicker.
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#7 Jake Kerber

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Posted 12 May 2005 - 01:50 AM

I wouldn't touch a non-modified, Home Depot available 5500w putt putt for use with HMI's--magnetic or flicker-free.

Often, the governor on those things cannot handle the way HMI's draw power and will try to compensate, thus creating fluctuations or pulsing. Having said that, they will sometimes work without problems, so you can try it but you're taking a big risk.

I have successfully used the Honda EU series portable generators with HMI's. I think the largest one available is 3500w or 3000w. The 2000w gennies are great because you can easily carry them and they are fairly quiet.

-Jake Kerber
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#8 Kevin Zanit

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Posted 12 May 2005 - 02:34 AM

I ran a 4k w/ magnetic ballast on an E&E modified 6500 with no problems.

My gaffer did what Bob's did. He ran the 60amp the distance it needed to go, and then put a splitter on (at the end of the run). On one connector, he put the ballast, on the other he put the in line meter. You need to put it at the end of the run to account for the line loss, etc.

My gaffer really did not want to do this arrangement, but we had no choice. It worked fine, but barley. We got a very new generator that was well maintained. Without that, I doubt it would work.


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#9 Dominik Muench

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Posted 12 May 2005 - 02:50 AM

stupid questin: can a generator or those magnetic ballasts cause any electromagnetic interferrences ? with other electronic equipment on set ?
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#10 Sam Wells

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Posted 12 May 2005 - 10:34 AM

I would be interested to know if anyone got away with using a non crystal sync generator and an electronic flicker free ballast??
Tim

http://www.hondapowe...delName=eu2000i

<{POST_SNAPBACK}>


Yes, 'got away with it' is the operative phrase.

What the others have said.

-Sam
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#11 Tim Tyler

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Posted 12 May 2005 - 12:01 PM

Thanks, all.

Looks like I'll go for the Honda EU2000 for about $1k.
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#12 Laurent Andrieux

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Posted 13 May 2005 - 03:50 PM

... and plan to check voltage and frequency as was said !
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#13 Tomas Koolhaas

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Posted 13 May 2005 - 08:24 PM

Hello,
A while back I shot with a construction generator 5,500w (if I remember correctly).
We used a 1,200w arri fresnel HMI w/ magnetic Ballast, it flickered like crazy!! so much so that the flicker was visible to the human eye.
I would not recomend ever using a HMI with magnetic ballast with a generator that wasn't puprose built for production usage (one with governed power) niether would my gaffer.
Cheers.
Tomas.
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#14 Mark Sasahara

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Posted 15 May 2005 - 12:08 AM

The producer bragged about what a deal he got for a Honda putt-putt genny. The genny was a bargain because it wasn't crystal controlled. The magnetic ballasts flickered badly. There was nothing we could do since it was too late to get a crystal genny. We shot and the footage looked like poop. I wasn't happy that they disregarded my insistence on the "expensive" generator.
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#15 Paul Bruening

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Posted 17 May 2005 - 09:44 PM

Hello,

You can use 1K Dichroic pars and forget about the flicker hassles of HMIs. I blimp my putt-putts and get good service out of them. I just stay away from the pricier HMIs.

Hope that helps.
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#16 Kevin Zanit

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Posted 18 May 2005 - 12:39 AM

Yes, but the 1k dichroics are expensive, and far less efficient.

I knew a DP who hated HMIs, so he would use Dinos and 9-lights with the dichroics (which I might add are several hundred dollars more than their non- dichroic counterparts) and they would get destroyed by a 4k PAR. They are not very efficient, and they have a rather short life.


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#17 Gilbert

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Posted 23 May 2005 - 12:45 AM

I would be interested to know if anyone got away with using a non crystal sync generator and an electronic flicker free ballast??
Tim


You can always use a non crystal sync generator with an electronic flicker free ballast such as an Arri, Power gems, LTM or Lightmaker, because they all self regulate the output power to the globe, even, for example a 120vac ballast, if the the voltage from the generator is fluctuating from 100vac to 130vac .
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