I have the following questions regarding US-style IS ballasts.

1: Similarities
I know that most magnetic rapid-start ballasts are very similar to CWA HID ballasts, but is this also true for magnetic instant start ballasts? Or are they more like HX HID ballasts?

2: Configuration
I also know that dual-lamp RS ballasts in the US operate the lamps in series. Is this also true for instant start ballasts? If they do indeed have capacitors in the circuit (like CWA) it could maybe have 2 capacitors and operate the lamps in series but I am not sure if this is the case or not.

3: Striking
I also know that magnetic instant-start ballasts just use a very high OCV to strike the lamps, but is this also true for electronic instant start ballasts? I wouldn’t be too surprised if they just used a high voltage pulse.

Thank you all again!

3. Both magnetic and electronic instant-start ballast use high OCV to start the lamp with cold cathodes and connects one wire to each end of the tube.
1. I think magnetic instant start ballast are considered an autoleak transformer. Some can even start LPS lamps like SOX 180W, SOX-E 135W and the linear Thorn SLI-H 200W HO LPS lamps.

2. Yes, it (along with the bleeder across one lamp) reduces the need for OCV per lamp, so reduces the OCV*Ilamp product, which is a figure dictating how big and expensive the ballast will be. But it to some extend complicates the safety - it becomes more difficult to prevent the ballast from generating high voltage when the lamps are not fully inserted (need for interlock switches in the sockets insulated from the lamp contact,...), so when the worker is manipulating with the lamps when the power is ON (if the "hot" side is inserted into the socket and the worker touches the other lamp terminal, the lamp may ignite and the worker may get shocked)...



3. Fluorescent (and also LPS) electronic ballasts use to use high frequency drive and use resonance boost to generate the high voltage for ignition, so the main circuit can work way more efficiently (even for its frequency) when the lamp is completely started (ignited and electrodes warmed up). Magnetic ballasts need to be wound for sufficient OCV, or need some OCV booster capable to deliver sufficient power (like electronic SOX ignitors). The thing is, with low pressure lamps is not enough just to ionize the gas, you also need to drive the lamps at sufficient power when the electrodes are still cold (so have high cathode drop, 100's V per lamp), so the cathode losses warm them as quickly as possible, in order to limit their sputtering damage.

High pressure lamps usually need the high voltage only for an initial ignition, as the anode column drop (the part of the discharge voltage drop dictated by the gas fill properties like pressure or so) on cold lamps is low enough so there is sufficient room for the extra cathode drop of cold electrodes.