Necessity of "photoflash" caps for strobe?

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Oznog

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I need to get a good storage cap for flashing a pretty big strobe tube.

I have noted that HV caps for camera flashes and strobes usually have a "photoflash" in their description, often marked on the cap. However this larger strobe tube requires a higher voltage than those camera flash caps. Of course two could be put in series but this will halve the capacitance, there are issues with keeping the voltage in the middle balanced. This would probably require more than 4 of these "photoflash" caps.
A cap like this would be perfect:
https://www.allelectronics.com/cgi-bin/category.cgi?category=140300&item=EC-1545&type=store

But it doesn't have a "photoflash" rating AND the tube has a 450V nominal voltage so it will need to be driven up there. The temp will be not be high though- temp strongly affects voltage ratings and that rating is probably for 105C. There is a significant voltage rating margin running 450V at say 35C. I will probably also need 2 caps which should halve the current from each cap which I think is the primary issue.

Any educated opinions on whether it will work in this duty?
 
Howdy
I have a relatively small flash unit which has a 330V, 280 uF cap ..
That photo flash rating means what...?
 
I assume photoflash means it is capable of high current discharge. A flash can take amps. If the cap's plates are thin foil this can tear them up. Also a capacitor's dielectric is always stressed more when high dV/dT rates occur. Still I don't have any hard information on what constitutes a "photoflash" cap in industry terms.
 
Yea an photoflash is made to stand more high curent discharges than normal caps.Thats all.They are also high voltage becose the flash tube needs high voltage to spark.(It also needs about 10kV to fire up)
 

I'm presuming you're looking at something like a disco strobe?, they commonly use normal electrolytics - I've never seen any specific capacitors used, I doubt anyone makes anything like that?.
 

The link you posted shows an electrolytic suitable for mains voltage levels (450 standard rating). It will have a higher than desirable ESR so perhaps you will not be able to get the peak current in the discharge you are looking for for the tube.

2 caps in series share the same current (definition of series) with double the voltage rating (provided they share equally - ballast resistors is common). To maintain the quality performance of the "flash" rated caps, you will probably want to just build a network using these types to get the capacitance you need at the voltage you need. More parts, but it could save you alot of headaches down the road if the alternatives keep destroying themselves (due to temps)
 
Mallory makes cap's just for this purpose, ( type EAF ), they have very low ESR, high ripple current ratings, low leakage, and are generally "overbuilt" compared to the low-cost standard ( read crappy ) general purpose electrolytics.

They are similar to the old "computer grade" capacitors with screw terminals or heavy snap-in leads in the larger sizes.

I have built strobes with normal caps before, but the first thing to pack it in was always the electrolytic.
 
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