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So I bought a mini kino flo dimmable ballast

kino flo ballast

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#1 Freya Black

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Posted 16 October 2015 - 11:11 AM

Well I picked up this little ballast for a mini kino flo which is a little thing for lighting car interiors etc. It normally powers special little kino tubes but I wondered if I could get away with powering more off it and what kind of limitations such a ballast might have.

 

Freya


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#2 Freya Black

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Posted 16 October 2015 - 11:21 AM

Kino_Flo_BAL_139X_Mini_Flo_Ballast_4_Pin


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#3 Freya Black

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Posted 16 October 2015 - 11:23 AM

and heres a link to it:

 

http://www.bhphotovi...last_4_Pin.html

 

Freya


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#4 Edward Lawrence Conley III

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Posted 16 October 2015 - 11:55 AM

Contact KinoFlo directly :)


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#5 Will Barber

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Posted 16 October 2015 - 10:39 PM

I don't know what the exact watt output on that thing is, but I know the Kinos it powers aren't very strong. May be possible to run LED's off it, but you'd have to solder on the 1/4" connector. 


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#6 Phil Rhodes

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Posted 17 October 2015 - 04:34 AM

No, you can't run LEDs from it. Entirely different animal.

 

You can probably just get a small T5 fluorescent tube and run that. I'm not sure what the design wattage is. Full-size Kino tubes are more powerful than the equivalent size of standard types, but I'm not sure that's true of the miniature ones. Compare like for like size-wise and work it out.

 

P


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#7 Freya Black

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Posted 17 October 2015 - 05:27 AM

No, you can't run LEDs from it. Entirely different animal.

 

You can probably just get a small T5 fluorescent tube and run that. I'm not sure what the design wattage is. Full-size Kino tubes are more powerful than the equivalent size of standard types, but I'm not sure that's true of the miniature ones. Compare like for like size-wise and work it out.

 

P

 

The listing I linked to claims that you can use both 9 and 12 inch tubes (although I thought the actual original fixture took a 9 inch tube) and it claims to draw 1A with the 12 inch tube so that would suggest a rather pathetic maximum of 12 watts.

 

The unit normally comes with a little 12v power supply tho. I could obviously replace that with something more substantial but I'm wondering what is going on inside the ballast and whether the ballast itself will be power limited in some way.

 

Freya


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#8 Mark Dunn

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Posted 17 October 2015 - 05:28 AM

deleted


Edited by Mark Dunn, 17 October 2015 - 05:28 AM.

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#9 Freya Black

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Posted 17 October 2015 - 05:54 AM

The other possibility might be running multiple tubes off the ballast. Is this possible or does each tube need its own ballast.

 

I'm just curious about it all more than anything else.

 

Freya


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#10 Phil Rhodes

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Posted 17 October 2015 - 06:03 AM

whether the ballast itself will be power limited in some way.

 

Yes, it is.

 

No, you can't run more than one tube from the same ballast. Well, you possibly could, in series, but it wouldn't work as specified.


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#11 Freya Black

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Posted 17 October 2015 - 06:33 AM

 

Yes, it is.

 

No, you can't run more than one tube from the same ballast. Well, you possibly could, in series, but it wouldn't work as specified.

 

 

Would you get dimming effects or colour temp effects or both do you think?

Ballasts are strange devices. I find the idea of stabalising the current rather than the voltage a bit odd and difficult to think about.

 

Freya


Edited by Freya Black, 17 October 2015 - 06:35 AM.

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#12 Phil Rhodes

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Posted 17 October 2015 - 10:58 AM

Both.

 

The current through (most) loads is (generally) proportional to the voltage. So, what it's doing is measuring the current then adjusting the voltage until the current is at the desired level.

 

P


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#13 Guy Holt

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Posted 17 October 2015 - 01:07 PM

 

...... I'm wondering what is going on inside the ballast and whether the ballast itself will be power limited in some way.

 

Kino fluorescent ballasts are a Switch-mode Power Supply (SMPS) designed to perform all the same functions as a magnetic fluorescent  ballast but at a higher frequency. They first rectify the 60 Hz AC input to DC and then produce a very high frequency alternating current (20,000 - 50,000 Hz depending on the fixture) from the DC using an inverter and power conditioning components.

 

 

Kino_Ballast_Comparison..jpg

 

The high frequencies at which Kino ballasts operate is what makes them a suitable light source for film and television production. By converting the 60 Hz input frequency to between 20,000 - 50,000 Hz, Kino ballasts eliminate the problem of light intensity fluctuation associated with standard magnetic ballasts. At those frequencies the period of time between the off and on pulse of each cycle is so short that the illuminating phosphors do not decay in light output. 


 

Kino_Tube_Operation..jpg

Like the glowing tungsten coil of an incandescent lamp, the fluorescent phosphors become essentially flicker free. Electronic fluorescent ballasts also weigh less and don’t have the characteristic hum of magnetic ballasts. These characteristics of the Kino Flo high frequency electronic ballasts make them well suited for motion picture lighting.

 

 

Kino_Ballast_Schematic.jpg

Schematic of typical  of electronic ballast: L-to-R consists of half-bridge rectifier, conditioning capacitor, DC/AC Inverter.

 

All Kino ballasts utilize a Diode-Capacitor circuit on the front end (to the left of the dashed line in the schematic above) to first convert the AC line input to DC. A pair of MOSFETS (to the right of the dashed line in the schematic above) act as a high frequency DC to AC inverter to create the high frequency alternating current (20,000 - 50,000 Hz depending on the fixture) that drives the fluorescent tubes.

 

So that they can operate off of a car battery, the 9” Kinos separate these two stages in separate boxes - the MOSFETS in one and the Diode-Capacitor circuit in another.  This way 12V DC from a car battery can be fed directly to the MOSFETS to invert to high frequency alternating current. To operate them on wall outlets, there is a separate box that contains the Diode-Capacitor circuit that converts the 60Hz AC to 12V DC.

 

Unless power factor corrected the Diode-Capacitor circuit of an electronic ballast generates a high level of capacitive reactance, which leads to an inefficient use of power and the generation of harmonic currents (use this link more detailed information about how Fluorescent ballasts, as well as HMI & LED ballasts, operate.)

 

 

Guy Holt, Gaffer

ScreenLight & Grip

Lighting Rental & Sales in Boston 


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