Inductances of single Choke ballasts

Topics relating to lighting control gear, including magnetic & high frequency ballast and ancilliary devices such as starters, ignitors and switchgear.
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Globe Collector
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Joined: Tue Apr 24, 2012 12:37 pm
Favourite Manufacturer: General Electric Company of England
Area of interest: High Intensity Discharge Lamps_ Lamp Chemistry_Spe
Location: Hobart, Tasmania

Inductances of single Choke ballasts

Postby Globe Collector » Tue Jun 12, 2012 9:45 am

Here is a topic I'm sure nobody has addressed, just what are the inductances of lamp ballasts!
Well I have measured every damn choke I've got my hands on, so I'll share my findings with everybody!
There is quite a lot of data besides the inductance. I used two methods of measuring the inductance, an impedance bridge, a Philips PM 6302 was used for one method and a second method employing resonance was also employed. This method involves placing a known capacitance in parallel with the unknown inductance then sweeping the parallel resonant circuit with a sine signal generator in series with a 1K resistor and using the oscilloscope, connected across the resonant circuit to find the resonant peak, i.e. the frequency at which the voltage across the LC circuit peaked. From this frequency and the value of the capacitor, the inductor value was calculated.
I'll call these "Lbgr" and "Lres" respectively. So starting at the chokes for the lowest power rated lamps and working up we have.....


Brand......................................ATCO
Type.......................................EC13
Lamp......................................13w C.F.L.
Tap.........................................240v
Lbgr........................................2.78 Henrys
Lres........................................2.43 Henrys
Parasitic Resistance......................133 Ohms
I squared R loss............................3.62W EDIT (21.8% of Circuit Power)
Resonant Frequency with 1uF Cap.....102Hz
R.M.S. Current............................165mA
P.F.C. Cap value for 0.9..................2uF
Inductive reactance at 50Hz.............765 "Ohms"
Inductive reactance at 60Hz.............917 "Ohms"


Brand............................................ATCO
Type.............................................ECLL18
Lamp............................................SOX-18
Tap.................................................C..................................................La
Lbgr...............................................200mH.............................................1.2H
Lres...............................................210mH.............................................1.17H
Parasitic Resistance.............................2 Ohms............................................33 Ohms
I squared R loss...................................250mW.............................................4.0w Edit (18% of Circuit Power)
Resonant Frequency with 1uF...................N/A................................................147Hz
R.M.S. Current.............................350mA.............................................350mA
P.F.C. Cap value for 0.9..........................N/A.................................................5uF
Lamp Arc Drop.....................................N/A.................................................57v
Inductive Reactance at 50Hz.....................70 "Ohms"...........................................367 "Ohms"
Inductive Reactance ar 60Hz..................... 79 "Ohms"..........................................441 "Ohms"

O.K., There's two of about 22. From my viewpoint the first two parameters, "Brand" and "Type" mean a lot less to me than they would to someone like Kev, who sees these things every day in the course of his work, but it is all the other things which place them into a wider electrical context.
I'll list two more, for 18w T9/20w T12 tubes. One is a European one taken out of a Polish Zyweic Beer sign.


Brand...................................................Vosslo-Schwbe
Type.....................................................L18
Lamp...................................................18w, 2' T9 Fluoro Tube
Tap......................................................230v
Lbgr.....................................................1.28H
Lres.....................................................1.20H
Parasitic Resistance...................................51 Ohms
I squared R loss...........................................5.5W Edit (23.4% of Circuit Power)
Resonant Frequency with 1uF.........................145Hz
R.M.S. Current.........................................330mA
P.F.C. Cap for 0.9......................................2.9uF
Power Factor Without any Cap........................0.34
Xl at 50Hz..............................................377"Ohms"
Xl at 60Hz..............................................452 "Ohms"

Brand...................................................ATCO
Type.....................................................EC18/20
Lamp.....................................................18w, 2' T9 "20w, 2' T12 Fluoro Tube
Tap........................................................240v
Lbgr........................................................1.42H
Lres........................................................1.34H
Parasitic Resistance......................................53 Ohms
I squared R loss...........................................7.25W Edit (Approx 25% circuit Power)
Resonant Frequency with 1uF............................137Hz
R.M.S. Current.............................................370mA
P.F.C. Cap for 0.9.........................................3.8uF
Power Factor Without any Cap...........................0.31
Xl at 50Hz..............................................437"Ohms"
Xl at 60Hz..............................................524 "Ohms"


If anybody shows interest I will list another 30 odd chokes I have measured. The largest was an ATCO OGB700 for an MBF/U 700w Mercury lamp with an inductance of 86.5mH.
Last edited by Globe Collector on Wed Jun 13, 2012 7:01 am, edited 1 time in total.

Todd-uk
Posts: 66
Joined: Fri May 13, 2011 6:03 pm
Area of interest: Fluorescent lamps

Re: Inductances of single Choke ballasts

Postby Todd-uk » Tue Jun 12, 2012 2:56 pm

I squared R loss...........................................7.25W for an 18 watt tube? thats almost half the power of the tube no wonder the eurocrats want rid of inductive ballasts

Is my comment treason?
Todd

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Globe Collector
Posts: 73
Joined: Tue Apr 24, 2012 12:37 pm
Favourite Manufacturer: General Electric Company of England
Area of interest: High Intensity Discharge Lamps_ Lamp Chemistry_Spe
Location: Hobart, Tasmania

Re: Inductances of single Choke ballasts

Postby Globe Collector » Wed Jun 13, 2012 6:49 am

I'ts nowhere as bad for the bigger chokes, but these little ones with thousands of turns of really fine wire do tend to be rather lossy. Same applies to tiny transformers, little ones, below 10VA, you know the little P.C.B. mounted ones, can be as much as only 50% efficient. But take a big one, say 2.5KVA, typically it will loose about 25 watts in I squared R and eddy current losses in the core, so about 1% for these bigger ones. Real big distribution ones in the 500KVA area are more like 0.05% lossy.
Similar situation exists with lamp chokes. The figures above do not include eddy current losses in the cores, but these are actually worse for the bigger cores (because the currents have a greater volume to circulate through and the laminations have greater contact area) and for a bigger choke contribute a greater proportion of the total losses even though the total is proportinately a lot less.

I'll list figures for some of the bigger ones....


Brand....................................................ATCO
Type......................................................OGS150
Lamp.....................................................SON/ SON/T 150w
Tap.......................................................240v
Lres......................................................305mH
Lbge......................................................310mH
Parasitic resistance......................................3.5 Ohms
I squared R loss...........................................11.3 watts (7% of circuit power)
Resonant Frequency with 1uF............................280Hz
R.M.S. Current............................................1.6A
Start Current..............................................2.3A
Power Factor without Cap...............................0.34
P.F.C. for 0.9.............................................17uF
Lamp Arc Drop............................................100v
Xl at 50Hz................................................96 "Ohms"
Xl at 60Hz...............................................115 "Ohms"



Brand....................................................ATCO
Type......................................................OGS250
Lamp.....................................................SON/ SON/T 250w
Tap.......................................................240v
Lres......................................................199mH
Lbge......................................................198mH
Parasitic resistance......................................1.9 Ohms
I squared R loss...........................................17.1 watts (6.4% of circuit Power)
Resonant Frequency with 1uF............................357Hz
R.M.S. Current............................................3.0A
Start Current..............................................3.9A
Power Factor without Cap...............................0.38
P.F.C. for 0.9.............................................28uF
Lamp Arc Drop............................................100v
Xl at 50Hz................................................63 "Ohms"
Xl at 60Hz...............................................75 "Ohms"


Brand....................................................ATCO
Type......................................................OGS400
Lamp.....................................................SON/ SON/T 400w
Tap.......................................................240v
Lres......................................................115mH
Lbge......................................................114mH
Parasitic resistance......................................1.0 Ohm
I squared R loss...........................................21.2 watts (5% of circuit power)
Resonant Frequency with 1uF............................470Hz
R.M.S. Current............................................4.6A
Start Current..............................................c5.6A
Power Factor without Cap...............................0.38
P.F.C. for 0.9.............................................28uF
Lamp Arc Drop............................................100v
Xl at 50Hz................................................36 "Ohms"
Xl at 60Hz...............................................43 "Ohms"


Brand....................................................G.E.C.
Type......................................................FN884
Lamp.....................................................SON/ SON/T 4000w (HPS/U 400)
Tap.......................................................240v
Lres......................................................122mH
Lbge......................................................118mH
Parasitic resistance......................................1.1 Ohms
I squared R loss...........................................21.8 watts (5.1% of circuit Power)
Resonant Frequency with 1uF............................456Hz
R.M.S. Current............................................4.45A
Power Factor without Cap...............................0.41
P.F.C. for 0.9.............................................42uF
Lamp Arc Drop............................................105v
Xl at 50Hz................................................38 "Ohms"
Xl at 60Hz...............................................46 "Ohms"


Brand.............................................ULTRA TECH ELECTRICAL
Type......................................................HPSA600
Lamp....................................................HPS/U 600
Tap.......................................................240v
Lres......................................................91mH
Lbge...................................................Not Measured
Parasitic resistance......................................0.9 Ohms
I squared R loss........................................Not Calculated
Resonant Frequency with 1uF............................526Hz
R.M.S. Current..........................................Not Measured or Specified
Power Factor without Cap..............................Not Calculated
P.F.C. for 0.9.............................................60uF
Lamp Arc Drop..........................................Unspecified
Xl at 50Hz................................................28.3 "Ohms"
Xl at 60Hz...............................................34.3 "Ohms"


These are all the SON, elliptical bulb with a diffusing coating, can be used in the same fitting as mercury lamps, but require different control gear. 2/ SON / HPS lamps.">SON-T, tubular clear hard glass for floodlighting. 3/ SON-TD, tubular double ended clear quartz, the length and cap are equivalent to those of tungsten halogen lamps.">High Pressure Sodium Chokes I have measured. The 600w one at the bottom is rather scant on information, probably because I did not measure everything when I had it set up. Lamp voltages are difficult to measure without a true R.M.S. reading instrument because the waveform is almost square, however an average reading instrument would suffice if you are prepared to correct the reading mathematically. Actually, to get the I squared R losses you only need the lamp current, which is roughly sinusoidal and relatively easily measured on an average reading meter and the parasitic resistance of the choke, which can be measured on the resistance ranges of most meters.


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