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diff lights amps


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#1 Natalie Saito

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Posted 13 June 2007 - 12:32 PM

what are the typical amperage for each below?

(1) 1.2K HMI (fresnel)? are they consistent like tungsten? ex: tungsten (approx.)-- 1K = 8 amps, 2K = 16 amps
(1) 2 or 4 bank kinoflo

thanks!
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#2 Jonathan Bowerbank

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Posted 13 June 2007 - 02:01 PM

what are the typical amperage for each below?

(1) 1.2K HMI (fresnel)? are they consistent like tungsten? ex: tungsten (approx.)-- 1K = 8 amps, 2K = 16 amps
(1) 2 or 4 bank kinoflo



Watts/Volts = Amps

This doesn't change, regardless of the type of light you're using.

However, for example, the light output of a "2K HMI" would be stronger than a "2K Tungsten"...and it uses the same amount of energy.

Edited by Jonathan Bowerbank, 13 June 2007 - 02:02 PM.

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#3 Rick Sharf

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Posted 13 June 2007 - 06:15 PM

i was under the impression that kino's pull much less than frensels.
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#4 Jonathan Bowerbank

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Posted 13 June 2007 - 07:47 PM

They do, because they're fluorescent and use less wattage than incandescents.
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#5 robert duke

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Posted 13 June 2007 - 11:36 PM

on the kino ballast you will find a placard that tells you the amperage, same for the 1200 hmi. 4x4 kino draws 5.5amps, hmi's draw more power than the w/v=a formula and it differs with magnetic vs electronic. 1200 hmi draws roughly 13.5 amps. most electronic say on a small placard the amperage draw.
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#6 edward read

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Posted 15 June 2007 - 08:07 AM

what are the typical amperage for each below?

(1) 1.2K HMI (fresnel)? are they consistent like tungsten? ex: tungsten (approx.)-- 1K = 8 amps, 2K = 16 amps
(1) 2 or 4 bank kinoflo

thanks!



HMI's don't follow the w=va formula because of what is called "power factor". Essentially the lamp has a certain current load but the ballast that powers the unit also has a certain amount of current load. That's why a 1200 hmi can pull as much as 13.5 amps as stated above.

Kino Flo's follow the same principle except on a much smaller scale (their lamps have a smaller current draw)

1000watt light at 120volts pulls 8.33333amps a=w/v
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#7 Daniel Madsen

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Posted 15 June 2007 - 12:56 PM

You must treat tungsten lights completely different from HMIs. With tungsten lights you just use electricity to heat a filament- it's relatively simple. With HMIs you have to power a ballast which requires much more current because it is an inductive source. With an inductive source voltage lags behind amperage requiring more current at one time for the same power output. A 1.2 watt HMI actually requires between 18 and 20 amps. A 4ft 4 bank requires around 5 amps I think.

Edited by Danielle Frankinshten, 15 June 2007 - 12:56 PM.

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#8 JD Hartman

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Posted 16 June 2007 - 01:51 PM

An older ARRI 575/1200 mag. ballast draws 12a. But why post this question here? The answers are: on the web, just a Google search away; available from your rental house; in the equipment manufacturer's catalogs. Or are the members here your personal reserch service?
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#9 Natalie Saito

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Posted 16 June 2007 - 04:41 PM

A 1.2 watt HMI actually requires between 18 and 20 amps. A 4ft 4 bank requires around 5 amps I think.


so hmis of equal wattage requires more power..got it. but 1.2k requires 400 or 200w?? thats a lot. im thinking 400 or 300k i wont be able to or do I want to rent a generator. i was leaning toward hmi because its daylight balanced.
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#10 Matt Sandstrom

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Posted 19 June 2007 - 05:09 AM

Watts/Volts = Amps

This doesn't change, regardless of the type of light you're using.

while that's true when the current and voltage aren't in phase the calculation gets more complicated than i think you realize. hmi's typically draw a bit more than tungsten since they're inductive and thus turn the current out of phase, and it also depends on the power source.

/matt

EDIT: that was a bit redundant, but what i mainly wanted to say is that there's nothing wrong with the formula, but as so often before there's more than meets the eye. everybody knows that e=mc^2 but we're probably few here who know why that is important. :-)

Edited by Matt Sandstrom, 19 June 2007 - 05:13 AM.

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