I like to run older rounded top Philips SOX lamps with metallic arc tube supports on dedicated electronic ballasts (Philips EXC). I wonder if this can cause problems and shorten the life of such SOX lamps as maybe the metallic parts gets capacitively charged due to higher frequencies of such a ballast may alter their functionality. What do experts say about this?

Thanks in advance.

Michael

I don't expect any particular issues in the case you are mentioning because although capacitive currents between the burner and the metal frame will be higher, this will not necessarily cause any electrolysis of sodium in glass. For that problem to arise you need much lower frequencies (mains) or DC.

Ok I see. That make sense. Thank you Max for the explanation. 

We found that running a 35W SOX lamp on an electronic ballast versus the good old magnetic lump made quite a difference. 

Despite both ballasts being the correct rating the electronic one was outperformed hands down by the magnetic one.

Ok I find that the lamp on an electronic ballast runs up slower than on magnetic.
The reason why I have chosen the electronic gear for my to SOX converted fixture is that it is weights much less than that with a leak transformer and capacitors. This is a important point as these fixtures are often used as stage lighting in our theater.

That sounds reasonable, we don't have to bother with weight considerations for our ballast boards