@Caroline
That is quite the system! Very impressive. How low is your typical wall voltage (if you don't mind me asking)? There has to be some sort of rule in place to govern how low it can legally be in a supply.

Nine months without power is outrageous! That must have been fun...

Your power situation sounds like a nightmare!

I experience it pretty much constantly, brownouts, not drunkards crashing against utility poles, that's another fun story.

Had to come up with a way to step-up the power for the lights because they're all incandescent (regular and halogen) and choke fluorescents for the kitchen, I ended up adding a subpanel next to the fusebox that takes care of that by using autotransformers and a custom control board, there's an override contactor that's supposed to close and bypass the circuit when the voltage gets past 230, but in the almost 4 years that system has worked it never happened, the xfrms can only bump 20% of the input V, they're made with an absolute low of 200V in mind, but ours can go much lower, to around 170 on a hot summer day, that if nothing blows up on the supply side.


The only limitation is it's only for the lighting circuits, the sockets remain at low voltages so that's why all of our desk/table lamps are low voltage driven by electronic power supplies, they can tank the low input and output stable 12V, if they were straight to mains most lamps would be really dim and flickery.


The only crash incident involved a drunkard smashing his truck at 180km/h against an utility pole nearby, it ripped the wiring on both directions and we were out of power and phone for 9 months. Generator can't run constantly so it was only to keep the fridge working twice a day, no landline = no internet so I didn't even use the computer. No such thing as same-day fix here, and power is state-owned.

Snappy strip itself has higher stresses, so higher risk of fatigue cracking...

Some well-made glow starters actually snap because of momentarily sticking the electrodes, giving a well defined preheat time on a first try.
 

AFAIK, LPS lamps were not especially popular in USA compared to Europe. May be no one really bothered to optimize ballasting for somewhat niche product. You can also consider reduced service costs vs saved electricity cost.

Sure, poor ballast efficiency very much likely driven system efficiency of American LPS luminaries below of what is achievable with HPS lamps.

@LightBulbFun
Very interesting, I don't think any choke ballasts were ever made for LPS in the US but I may be wrong. Are there any US-based ballasts for LPS lamps that use ignitors that you know of?

@RRK
But isn't the whole point of LPS to have higher efficiency than HPS? Unless we are talking about the pre-HPS years here. I thought that was the whole LPS mission statement, to be the most efficient lamp. Were they still more efficient than HPS even when considering these high ballast losses?

Lamps like HPS and PSMH have relatively low open-circuit voltages because they use ignitors to strike the lamp.

MV lamps use an OCV of around 240V to strike, which is around as low as you can get considering the running voltage of ~130V. I hear that the OCV has to be around double the running voltage for an arc to be stable. MH is very similar (around 300VOC).

But with LPS this doesn't seem to be the case. For example, a 90W SOX lamp has an arc drop of 112V. This means that this lamp can run with an OCV of around 230V. But it can't strike on voltages that low, which is why the ballasts output ~480VOC. But isn't this wasteful? Why not just have a ballast with 230VOC with a ~1kV ignitor? I feel like this would be easiest to manufacture and also more efficient.

Any thoughts?

Almost certain, since electricity is relatively inexpensive in USA, manufacturers preferred extremely robust, but really inefficient high-OCV leak transformers. Back in 1970-1980s semiconductor circuits were still considered a big step back in terms of reliability.

@LightBulbFun
Yes! Exactly like that, I didn't know those existed. Why aren't they all like that?

you mean like the

WRTL Thryactor?

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-184846

or the Venture SZ090K245

https://ledspares.co.uk/products/sz090k245

or the


ok ill stop now


most modern SOX ballasts *are* like that.... (for those with arc voltages compatible with 240V OCV, those of higher arc voltages are run on lower-loss CWA setups sometimes)

@LightBulbFun
Yes! Exactly like that, I didn't know those existed. Why aren't they all like that?

Lamps like HPS and PSMH have relatively low open-circuit voltages because they use ignitors to strike the lamp.

MV lamps use an OCV of around 240V to strike, which is around as low as you can get considering the running voltage of ~130V. I hear that the OCV has to be around double the running voltage for an arc to be stable. MH is very similar (around 300VOC).

But with LPS this doesn't seem to be the case. For example, a 90W SOX lamp has an arc drop of 112V. This means that this lamp can run with an OCV of around 230V. But it can't strike on voltages that low, which is why the ballasts output ~480VOC. But isn't this wasteful? Why not just have a ballast with 230VOC with a ~1kV ignitor? I feel like this would be easiest to manufacture and also more efficient.

Any thoughts?

you mean like the BSX90?

https://www.lighting-gallery.net/gallery/displayimage.php?pos=-204553