Burnout of 6300 Lumen Light Bulb: Why?

[russ_watters]

Welcome to PF!

InterestedCRL -- I think incandescent filament bulbs have greatly lost their lasting quality since Congress passed laws allegedly to 'save enengy', which affected that type of bulb quality. But I think more unnecessary burnouts and more sales were the real motivation of the law, and not consumer health, safety, nor 'pro-environment'.

Erm, huh? The sales of most common incandescents were banned, so their sales plummeted to essentially nothing. So no, the law certainly did not increase sales of incandescents.

 

[Tom Rauji]

InterestedCRL -- I think incandescent filament bulbs have greatly lost their lasting quality since Congress passed laws allegedly to 'save enengy', which affected that type of bulb quality. But I think more unnecessary burnouts and more sales were the real motivation of the law, and not consumer health, safety, nor 'pro-environment'.

Why would you think that? Logically, a more energy efficient incandescent bulb of a given basic style would have to run a hotter filament. This would increase efficiency, but reduce life. Also, bulbs are now largely produced in China.

Filament type vacuum tubes produced in the USA lasted 20-30 years and were nearly 100% good out of box. The same tube, produced in China, has an out-of-box infant mortality rate of about 50%. Those that do go beyond infant failure last about 2-3 years at best. It seems pretty strange to come up with a government conspiracy theory when multiple facts point to production issues.

I'm not saying short life is not an issue, but it is a fact that more efficient incandescent bulbs have shorter life (all things equal) and Chinese products are often terrible quality.

 

[sophiecentaur]

Too many wives tales about filaments. Shut down speed or ramp-down of the filament is meaningless.

That's an interesting observation and it makes sense; the peak current will certainly be during the initial 100ms or so and that will be when most power is dissipated by the filament. I have noticed that high power filaments (300W and 500W stage lights) do seem to develop 'rough' sections along their length. That could be what you are referring to.