Thanks. But I've heard about US rapid-start electronic ballasts, that had the same behaviors to the classical US magnetic rapid-starts with lamp EOL (EOL lamp not working, rest lamps glows dimly), whats don't occurs with our non programmed-start electronic ballasts for 2 lamps or more.
The question is, what exactly is called "RS". Many programmed start ballast have the starting sequence lasting around the 0.5s, with the brightness increasing gradually after ignition (just slow frequency sweep during start). These qualify as Programmed start (if we take the meaning as first heating and only then ignition), just because it suffices with less than 1s, it earned the marketing designation as "RS".
What you describe looks like quite dumb implementation without any protection circuits (likely just a IRS2153 with few components extra for the frequency sweep) just without any EOL protection. I think the main reason is, similar European ballast will have the EOL protection, which will shut the ballast down. Why it is missing in the US design? Could be because they want to decouple the multiple parallel lamp resonator circuits from each others failure (and then use the same inverter even for single lamp ballasts), with series connection that is of course not physically possible.
And even when the protection is there, but is based on e.g. hard switching frequency rampup and and a core saturation detection, the working lamps on the inverter prevent the circuit from hard switching, (so frequency rampup, so core saturation in the failed channel), so causing the protection to not trigger.
In Europe the higher power lamps (those needing parallel configuration) are very rarely used more than one on a single ballast, the reason is it does not bring that much saving anymore, but it brings wiring problems (the HF ballast impose limitation on certain wire lengths, with larger lamps it could be problematic to have all sensitive wires short with more than one lamp). In the US they seems to care way less about that (long wiring with 4 lamp instant start,...)
Also, if SRS should be Series Rapid-Start and not Semi-Resonant Start, so why the starting of the british SRS ballasts looks different than the starting of the US rapid-start ballasts?
How different? You mean the US ballast first glows dimly and then slowly brightens, vs the RSRS does not glow at all and then suddenly lights up (not that I have any experience with the SRS, it is just a hint of a kind of difference would suspect given the circuit)?
There are three details, which may make some differences between the US RS and the SRS (note, the differences below are just the tendencies towards that behavior, both of these may behave in the compete range from delay-with-nothing-immediate-full-brightness to gradual increasing of the brightness from zero to full):
- The US RS may use higher OCV, the SRS has just the mains voltage as OCV. That means the US may ignite some (glow) discharge before the electrodes warm up andf the warming up only represents itself by the slow current increase.
- The US RS use to use series capacitor as the ballasting impedance, while the SRS are only inductive. That means at the moment the lamp start to rectify, the SRS feeds way higher currents (nearly the full rated current even when just one cathode is emitting) and these currents then provide quite significant heating to the other cathode as well, so practically make the startup from that point practically instant. The series capacitor in the US RS then causes the curent to correspond to a kind of average voltage between both polarities, so once one cathode reaches emission, the brightness ramps up partially and after the other cathode reaches it, it does other step to the full brightness.
- The filaments are supplied in the US RS by a voltage source (filament winding), but in the SRS by a current source (the compensation capacitor current). The constant voltage source means way higher heating power, so fast temperature rampup when the filaments are cold and slower when they warm up a bit, while the current feed of the SRS means the cold filaments are warming up very slowly and only when theu heat up a bit and so increase their resistance, the warming up gets quicker. That means the US reaches the onset of emission quicker and then slower builds up the strength, while the SRS "nothing happens" for most of the time and then the rampup of the emission happens way quicker.
Plus one additional: The US lamps have thicker filaments (3.6V rated), which way less respond to the actual arc current (mainly on the anode side) than the thinner European lamps used for SRS (~9V or so rated). That means the warming up of the SRS is strongly affected by the actual discharge, so once the lamp ignites at least partly, the warming up speed up a lot. With the heavier gauge of the US lamps the warmup is less affected, so just continues slower.