I wish to understand fully the starter circuit integrated into Philips' 13 watt Compact Fluorescent Lamps like the 13W PL-S GX23; 2-Pin Base 046677230104. So this 2 pin tube is actually a conventional 4 pin tube that utilizes a preheater. In which case, I may have to surgically remove the starters before power is applied for the first time. My current understanding is that a bimetal strip gets hot and connects the tube's electrodes to a series circuit to boil off some ions in the "preheat" stage then the bimetal strip cools, breaks the circuit, and the tube should light up if enough ions and mercury are present. My ballast does not do that, it just punches the arc through the cold cathodes and does a great job doing it that way when driving a single tube. The $64 dollar question is: "Can it do that with three of these little tubes in series?"
Three possible outcomes of leaving the bimetal starter in place in order of most desirable:
1. Successful strike of the lamps and starter circuits never comes into play.
2. 200 volts melts/overloads some non important part of the the starter circuit and then is no longer a concern.
3. Bimetal strip fuses to post and creates a permanent series circuit which includes the tubes electrodes and that tube is ruined due to electrode meltdown. My luck would be that the tube cracks and the yucky mercury vapor escapes.
I have an experiment set up to put three of these CFLs in series. Ready to apply power, at the last moment I read on the box that they have integrated starters. Hold the phone - lets just step back and think about this for a bit.
The electronic ballast I have available and intend to use is a Sylvania QHE3x40DL/UNV ISN-SC. It puts out 20kHz AC @600 volts. Current flow would be 40W/600V = 67mA. If the series leg has 67 mA flowing through it then the voltage drop across each 13 watt bulb would be 13W/.067A = 194V. That is 3% below the desired 200V but this was assumed when the decision was made to go ahead with this experiment: 39 total watts instead of 40 watts. I wonder what the variability of the actual electrical load is from one 40 watt tube to the next. Can it be as much as +/- 2.5% and still meet the required quality standards?
An interesting demonstration and discussion was found here about driving tubes with DC. Once the lamp strikes; the power being input to the tube must be throttled back. I can only assume that my ballast handles that all on its own. OR I could go measure it - maybe now is the time to learn how to use my new clamp meter from Harbor Freight.
If I ever acquire a box full of 7.5 watt tubes, I can share with you my theory of using a 4 kHz chopper circuit ( using IGBTs of course ) to drive two "parallel" legs each containing 3 bulbs in series.
