Correct inductance of choke for running a 40w T12 on 220-240v mains?

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Topic: Correct inductance of choke for running a 40w T12 on 220-240v mains? (Read 492 times)

Laurens
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I have a plethora of inductors and chokes sitting around. But barely any 'official' fluorescent ballast chokes.

There's nothing that special about a choke for a fluorescent lamp, any inductor with the right power handling capability and inductance will do.

So does anyone have a list of how many Henry each type of magnetic ballast is? That way i can figure out if i can use certain transformer primaries with different taps as a magnetic ballast for tubes i don't have a 'proper' ballast for. Hell, i could even use a variac wired up as as a 'normal' inductor for setting exactly the right inductance.

Related: the correct running voltage and current for a 40w t12 is also welcome

Also related: the picture below.

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RRK
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Roman

Here is the reference data from an old Soviet book. In Russian, but pretty understandable. Left table is the reference for lamps, fluorescent and mercury (1970's data, but not much changed since) right table is the data for 'reference' low loss measurement chokes. Columns are Lamp power - Impedance - Nominal current - Power factor (only choke itself). Note that first two chokes are tabulated for 127V line voltage. Modern 18 and 36W tubes run on 20 and 40W ballast impedances, too.

Knowing an impedance, you can easily calculate the inductance. The aim is to get the right lamp current, and to verify it with an ampermeter. Remember, as tube voltage is non-sinewave, simple circuit theory gives only approximate results, exact formulas are rather bulky.

« Last Edit: February 03, 2024, 12:06:02 PM by RRK »

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Laurens
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Thanks, this is very useful! Engineering is an international language, although i can't speak russian, i can transliterate cyrillic a bit to make sense of datasheets.

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WorldwideHIDCollectorUSA
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HID, LPS, and preheat fluorescents forever!!!!!!

For virtually all 4 foot 40W T12 fluorescent tubes in the world, the arc voltage drop is about 100V while the operating current is about 430mA.

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Desire to collect various light bulbs (especially HID), control gear, and fixtures from around the world.

DISCLAIMER: THE EXPERIMENTS THAT I CONDUCT INVOLVING UNUSUAL LAMP/BALLAST COMBINATIONS SHOULD NOT BE ATTEMPTED UNLESS YOU HAVE THE PROPER KNOWLEDGE. I AM NOT RESPONSIBLE FOR ANY INJURIES.

WorldwideHIDCollectorUSA
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HID, LPS, and preheat fluorescents forever!!!!!!

Quote from: Laurens on February 03, 2024, 12:14:19 PM

Thanks, this is very useful! Engineering is an international language, although i can't speak russian, i can transliterate cyrillic a bit to make sense of datasheets.

I also recommend using Google Translate to be able to read the document in your native language. I often use google translate to read Japanese lighting documents in English.

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Mandolin Girl
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Oil Lamp Addict

*Other translations websites are available.

We won't touch anything associated with Google because they'll track you to within an inch of your life if they can.

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Hugs and STUFF Sammi xXx (also in Aberdeen)
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RRK
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Just use a separate Firefox profile and clear cookies and cache before and after. Google will not have a chance to link your request to your other web activity. Until your browser or your provider do not forcibly insert an 'advertising id' cookie. Likely not practiced outside mobile networks and outside US and probably a violation of GDPR in Europe.

I too do not like that 'metadata hoover' behavior of Google though most people do not care...

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