AC/DC inverter for fluos at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > Photon Management

Photon Management
Shine an ever-loving light on you.


Reply
 
Thread Tools Search this Thread
Old January 25th, 2007, 03:39 AM   #1
Trustee
 
Join Date: Oct 2003
Location: Rio de Janeiro, Brasil
Posts: 1,137
AC/DC inverter for fluos

I am a great fan of U-shaped fluos, in 36W and 55w versions. Spiral types are also on the same group, but their housings protect them less.

Both make great, cheap, light and reliable soft light units.

What do they still depend on? AC power.

So I was pleasantly surprised when I found this DC to AC inverter:

http://www.all-battery.com/index.asp...ROD&ProdID=447

It's affordable, light and is pure sine-wave. That means it may be used on many things and have less noise.

In any case it would be a great partner for a portable set of fluo heads.



Carlos
Carlos E. Martinez is offline   Reply With Quote
Old January 25th, 2007, 07:05 AM   #2
Trustee
 
Join Date: Nov 2005
Location: Sydney Australia
Posts: 1,570
From my work with these kinds of inverters and fluro lights the term "pure sine wave" is a bit wobbly. I have one inverter that is real pure sine wave, <1% distortion and it's quite a bit more heavy and expensive and the fluros sound much happier running of it than the cheap inverters. HMIs on the other hand don't seem to care as much.

If you're into building your own stuff here's a tip.
Most of the electronic ballasts for those "D" tubes and even some CFLs will run off DC. The manufacturers may specify the correct voltage, it's typically around 350V DC for 240V inverters. So the thing is you can then use a DC to DC inverter which is more efficient and smaller than DC to AC. Just be warned, unless the lamp or ballast says it can run off DC it might die when you try. Never worried me killing a CFL but an Osram ballast is a bit too expensive.

Here's a kit for doing just this:

http://www.oatleyelectronics.com/kits/k111b.html
Bob Grant is offline   Reply With Quote
Old January 25th, 2007, 07:16 AM   #3
Trustee
 
Join Date: Oct 2003
Location: Rio de Janeiro, Brasil
Posts: 1,137
Quote:
Originally Posted by Bob Grant
From my work with these kinds of inverters and fluro lights the term "pure sine wave" is a bit wobbly. I have one inverter that is real pure sine wave, <1% distortion and it's quite a bit more heavy and expensive and the fluros sound much happier running of it than the cheap inverters. HMIs on the other hand don't seem to care as much.
I wouldn't dare put an HMI on an inverter.

Yes, I'm sure the term "pure sine-wave" is vague. They probably just filter it better or use better parts. Which is the one you are using? Do you power it from a car battery?

Quote:
If you're into building your own stuff here's a tip.
Most of the electronic ballasts for those "D" tubes and even some CFLs will run off DC. The manufacturers may specify the correct voltage, it's typically around 350V DC for 240V inverters. So the thing is you can then use a DC to DC inverter which is more efficient and smaller than DC to AC. Just be warned, unless the lamp or ballast says it can run off DC it might die when you try. Never worried me killing a CFL but an Osram ballast is a bit too expensive.
Not really too interested in doing such mod. Besides that we have 110v/60Hz in Brazil, even if electronic ballasts don't care about the frequency and are usually 110v/220v switchable.
Carlos E. Martinez is offline   Reply With Quote
Old January 25th, 2007, 08:02 AM   #4
Inner Circle
 
Join Date: Dec 2002
Location: Augusta Georgia
Posts: 5,413
I find the "Pure Sine Wave" claim to be suspicious.

It is difficult to create a "pure sine wave" with electronics.

It is possible with ferro-resonant transformers and motor-generators.

I suspect that "Pure Sine Wave" is the brand name.

I would like to see the output on an oscilloscope.
__________________
Dan Keaton
Augusta Georgia
Dan Keaton is offline   Reply With Quote
Old January 25th, 2007, 09:41 AM   #5
Trustee
 
Join Date: Oct 2003
Location: Rio de Janeiro, Brasil
Posts: 1,137
Quote:
Originally Posted by Dan Keaton
I find the "Pure Sine Wave" claim to be suspicious.
It certainly is.

Quote:
It is difficult to create a "pure sine wave" with electronics.

It is possible with ferro-resonant transformers and motor-generators.

I suspect that "Pure Sine Wave" is the brand name.

I would like to see the output on an oscilloscope.
No need to go so far. Let's assume they are a heavily filtered design, using large inductors, and we will probably get close to it.

If the source of this supply is a low level signal generator, which it probably is, it's not so hard to create that sine wave starting with a square wave.

The question are the amplification and the transformers.
Carlos E. Martinez is offline   Reply With Quote
Old January 25th, 2007, 07:32 PM   #6
Major Player
 
Join Date: Mar 2006
Location: Los Angeles
Posts: 439
What's wrong with running an HMI off an inverter? If you've ever used the DC versions of K5600's Jokerbugs, they are AC jokers that use simple square-wave inverters (separate box). Why no sine wave? Well, one of the great advancements of HMI technology was the invention of the flicker-free electronic ballast. That was in part due to ultrafast switching within the power supply, a.k.a. square-wave. While many electronics (and lamps for that matter) are designed for low frequency, 60hz power, electronic HMI's actually function just fine with square-wave supplies. Obviously, not all inverters are made equal, and the variance in the output voltage will sometimes fluctuate depending on the quality... however, I have never hesitated to use simple and inexpensive square-wave inverters with electronic HMI ballasts.

As for flo's, I've occasionally used cheap inverters with my fulham electronic ballasts, and they work just fine. Maybe there is some crazy reason why I shouldn't do it, but thus far, it seems to be in similar behavior as with HMI ballasts.
Jaron Berman is offline   Reply With Quote
Old January 26th, 2007, 01:34 AM   #7
Trustee
 
Join Date: Oct 2003
Location: Rio de Janeiro, Brasil
Posts: 1,137
You are right: why not use an HMI with an inverter?

I try it when I get the inverter.
Carlos E. Martinez is offline   Reply With Quote
Old January 26th, 2007, 08:23 AM   #8
Regular Crew
 
Join Date: Dec 2006
Location: Tampa-Orlando, FL
Posts: 124
Few years back I bought a 1000w inverter to power a K5600/400 HMI. When I first plugged-in the light the power supply made a loud buzzing sound. I was told by the K5600 engineer that the noise was caused by the unstable power source and it would eventually damage the power supply. He suggested that if I intended to use the light off my car to get a pure sine wave inverter, so I did, I spent over 1K for a 1200w pure sine wave inverter. I used a few time successfully until someone pointed out that that much drain could eventually cause some serious damage to my van electrical system. I did some research and they were right. I also know somebody who went as far having installed a second generator in his suburban just to maintain the added drainage, I wasn’t about to do that, instead I bought the largest and the best battery that I could find and started using the inverter off a separate battery. It worked well but I could only plug-in one light and was getting only about 15 minutes out of a full charge, and the whole thing was just too heavy for one person to move around. So two years ago I decided to buy a EU2000 Honda generator, something that I should have done in the first place, I could have saved money and aggravations.

www.EFPlighting.com
Nino Giannotti is offline   Reply With Quote
Old January 26th, 2007, 09:00 AM   #9
Trustee
 
Join Date: Oct 2003
Location: Rio de Janeiro, Brasil
Posts: 1,137
I take back what I said about the HMI. I won't try it when I get the inverter.

Can we go back to simple 55w fluo banks?...

This had been my initial proposal, mostly thinking on low-budget portable lighting for doc situations.


Carlos
Carlos E. Martinez is offline   Reply With Quote
Old January 26th, 2007, 09:15 AM   #10
Trustee
 
Join Date: Oct 2003
Location: Rio de Janeiro, Brasil
Posts: 1,137
Quote:
Originally Posted by Nino Giannotti
Few years back I bought a 1000w inverter to power a K5600/400 HMI. When I first plugged-in the light the power supply made a loud buzzing sound. I was told by the K5600 engineer that the noise was caused by the unstable power source and it would eventually damage the power supply. He suggested that if I intended to use the light off my car to get a pure sine wave inverter, so I did, I spent over 1K for a 1200w pure sine wave inverter. I used a few time successfully until someone pointed out that that much drain could eventually cause some serious damage to my van electrical system. I did some research and they were right. I also know somebody who went as far having installed a second generator in his suburban just to maintain the added drainage, I wasn’t about to do that, instead I bought the largest and the best battery that I could find and started using the inverter off a separate battery. It worked well but I could only plug-in one light and was getting only about 15 minutes out of a full charge, and the whole thing was just too heavy for one person to move around.
To start with I never thought of using this inverter to connect to a car: only to a separate car battery. What battery was the one you used?

How much current did the 400 HMI ballast need? It probably is more than 400W.

In any case, if you take that value as a basic consumption, if I am not wrong, it would take us to around 40 amp consumption. Which would provide about 60 minutes from a 12v battery. That is: around 4.0A at 110v, multiplied for the DC/AC boost ratio (~9 times), would provide aproximately that. But I wouldn't trust the inverter working linearly up to its top power.

The probable reason to blame for it lasting only 15 minutes is that it might be designed to work with 14.5v, which is what cars supply. Same thing as with car audio amplifiers. And other loses they do not compute and are in small letterings somewhere.;)

Quote:
So two years ago I decided to buy a EU2000 Honda generator, something that I should have done in the first place, I could have saved money and aggravations.
How much could you get out of it? What about the noise?

That was something that I also considered, at least for rental.


Carlos
Carlos E. Martinez is offline   Reply With Quote
Old January 26th, 2007, 10:03 AM   #11
Regular Crew
 
Join Date: Dec 2006
Location: Tampa-Orlando, FL
Posts: 124
As I said, I should have bought it in the first place. I owned a dozen of generators throughout my career but I canít say enough about this little beauty. It weight 46lbs, itís the size and carries like small suitcase, it has a DB noise level of apx.55 and it supplies ultra clean power. I have a reel with 100ft 10/3 cord and unless you are in the middle of the night in very silent forest under normal daytime conditions you can not hear it over 75 feet away or at least is not affecting the audio in any way. In less noisy environments and if you are using a wide pattern mike just put it behind anything, a bush, your car or around a corner and any sound disappears. I use it a lot mostly with 2 K5600/400w or one 800w and when hot outside also a small fan for me. One tank of gas and forget it, but I always carry a one gallon safety gas can with me. At less than $1,000 itís a bargain and considerably less that good pure sine wave inverted of equal capacity. And when hurricanes hit here in FL itís ready to get hooked from my outside porch right into my fridge. Check out the specs.

http://www.hondapowerequipment.com/M...elName=eu2000i
Nino Giannotti is offline   Reply With Quote
Old January 26th, 2007, 11:04 AM   #12
Trustee
 
Join Date: Oct 2003
Location: Rio de Janeiro, Brasil
Posts: 1,137
Quote:
Originally Posted by Nino Giannotti

Cool!

For the noise I guess a foldable wooden box with foam on the inside walls might damp it quite easily.

Great!
Carlos E. Martinez is offline   Reply With Quote
Old January 26th, 2007, 04:56 PM   #13
Major Player
 
Join Date: Mar 2006
Location: Los Angeles
Posts: 439
It's true that for certain wattages, basically more than a couple hundred, it's FAR more efficient to just get a genny. The honda EI (?) series, or whatever the name of their small inverter gens is...are simply amazing. Extremely quiet, easy to use and small/light. Definitely lighter than the inverter/battery route most of the time. The reason one would choose an inverter is if you already have a cache of batteries (like film battery belts), or there's simply no way to use a genny. But runtimes are VERY short. With two battery belts, I get about 20 minutes out of a joker 400. That includes strike/stabilization time.

Back to the topic at hand. The reason tungsten lamps whine when you dim them or power them off odd sources is because the have a filament which physically vibrates. Sometimes, the switching of power (square wave) can cause the filament to jolt and vibrate fast enough to oscillate, and make a hum. Fluorescents don't have filaments. Fast switchin of square-wave power is not as big a problem, because there's no filament to vibrate. Usually, when you hear fluo's whine, it's either because of an old magnetic ballast, or because one of the electrodes had corroded enough to act like a filament and oscillate. As long as the ballast is fairly modern, it should have no problem using square-wave power, like that from a cheap inverter. So if you're trying to DIY some Kino's to light inside a car, I wouldn't worry too much about powering off a low-cost inverter. If you're outside, or not moving, then the sugestion to use a genny is a VERY good suggestion, much more practical. Beware, though, of cheap genny's. They sometimes put out unregulated power and are usually EXTREMELY noisy. Only the newest inverter genny's from companies like Honda and Yamaha are truly quiet enough to use near set (in this size range). If you have large power demands, it's probably best to rent a manned grip truck with an onboard genny. If you're under 4K of total wattage, you can get away with ganging 2 honda genny's in parallel.
Jaron Berman is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Photon Management

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 10:37 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network