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 Post subject: Re: SOX lamps
PostPosted: Fri Dec 19, 2014 3:10 pm 
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meppso wrote:
Thanks phosco152 for the info. The first tube I tried only the electrodes glowed.

I have seen lanterns running red all night. What would cause this?

Regards,

Andrew.



The link below has lots of info about SOX failure modes...

http://www.soxlamps.com/diagnostics_sub.htm


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 Post subject: Re: SOX lamps
PostPosted: Tue Jan 06, 2015 10:31 am 
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There is a more detailed explanation on James`s Lamptech site explaining `red burneres`, this exact conversation came up on another lighting site about SOX red burning, to which James pointed us to his information.
See here, its an interesting read!


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 Post subject: Re: SOX lamps
PostPosted: Wed Jan 07, 2015 1:12 pm 
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Hi All,

Some interesting information there about SOX tubes, thank you.

I agree with GreatNorburyStDepot's comment about SOX lighting being the most interesting out of all lights sources. I think this is because as a child in the 80s/90s a massive amount of Carlisle was illuminated by this light source including the area in which I lived. The road on which I lived had Revo Baby Daleks, the main roads had MA90s, my Gran's street had top entry Beta 5s and the road on which my school was on had GECZ9491s. So I think a lot of my love for SOX is nostalgic but compared to the new LED lanterns which just switch on SOX is fascinating.

Regards,

Andrew.


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 Post subject: Re: SOX lamps
PostPosted: Wed Jan 21, 2015 10:29 pm 
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It was the 180W lanterns on motorways that I always enjoyed seeing when I was younger. The sheer size of them, even to a kid who has no clue, were still noteworthy. I never liked the SON highmasts much, which I always remember as just being too glary.

Question: Am I right in thinking that SOX35 runs on SOX-E26 gear, albeit without the energy saving of SOX-E? I might need a replacement bulb soon for my MI26, 35W ones are going cheap on ebay and 26W is harder to find.


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 Post subject: Re: SOX lamps
PostPosted: Thu Jan 22, 2015 7:30 am 
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Yes "normal" SOX lamps should run on SOX E gear if the lamp is new. It will be run at the lower power rating of the E lamp as the operating current is reduced. This reduced operating current may not however properly run an old or used lamp.

However - and this is a common mistake by lighting contractors - an E rated lamp when run on conventional gear will not operate at the lower rating as the current provided by the conventional gear is higher than for E gear.


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 Post subject: Re: SOX lamps
PostPosted: Thu Mar 19, 2015 10:50 pm 
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GreatNorburyStDepot wrote:
sotonsteve wrote:
SOX lamps are becoming very expensive.


In the days when SOX was pretty much the universal choice for local authorities, manufacturers and wholesalers had a good, stable market for their products. I recall that the lighting departments in my area were generally supplied through a purchasing consortium of several authorities. Buying in a greater bulk would achieve better savings in the cost of SOX lamps, than on a single purchase order from a single authority. Whether this continues now is unclear, especially with the PFIs etc.

The other situation now however, is that SOX is a threatened species hereabouts, therefore a manufacturer that finds itself gaining an increasing share of this diminishing market is unlikely to be sustainable in the long term.

At the end of the day, the price of lamps is based on their production run quantity - more output, cheaper price. Will LEDs go the same way?



Is the Philips factory in Scotland the only one in the world still making SOX lamps?


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 Post subject: Re: SOX lamps
PostPosted: Fri Mar 20, 2015 5:39 am 
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The Philips plant at Hamilton is the only plant in Europe that is still making SOX lamps - for the UK, Dutch and Belgian markets.

The market for SOX lamps in the rest of the world is limited, one small area in California uses them although LED conversions are making in roads. China and Brazil also use them but all 3 are likely to have their own production facilities.


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 Post subject: Re: SOX lamps
PostPosted: Tue Apr 07, 2015 12:04 am 
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Anyone got any thoughts on running a Philips 135W SOX cap up vertical in a shock free environment? Most people will no doubt blindly say "don't do it!!" but I'm struggling to actually find compelling reasons why.

Philips themselves state their smaller SOX tubes can be ran in a universal burn position when installed in a shock free environment, most likely because of the dimples they employ on the tubes.  The design of larger lamps is largely identical to the smaller ones except they're simply longer. The same principle surely applies; but is not really tried and tested as there are few if any SOX lanterns which use a vertical lamp.

Weak spots of the lamp include the seal near the electrodes, that sodium can attack, but a cap up burn prevents this. Sodium may gather near the U bend if run cap up - but it does this anyway on used lamps.

Apart from "erm you're not really supposed to do that" does anyone have scientific reasons why it shouldn't be done?


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 Post subject: Re: SOX lamps
PostPosted: Tue Apr 07, 2015 4:20 am 
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The dimples in the arc tube are a Philips patent and other makes can't use the design without paying a royalty.

Smaller lamps can be run cap up, but not cap down as the sodium can migrate to the electrode end of the lamp. The electrode/glass seal is a weak point in SOX lamp design and pooling of sodium at that point aggravates the issue. Apparently there is a rumour that Philips changed the Mi26 to "cap at street end" from "cap at kerb" on the Mi50 to overcome this issue when the lanterns were used on 7 brackets which often had a slight up tilt.

Another issue with running lamps vertically is that the temperature gradient along the lamp becomes significant and the loss of heat from the ends is made worse. The U bend end is a major heat loss point, hence why for smaller lamps it is recommended to run cap up to minimise the loss. For the larger diameter 90/135/180W lamps, it will be much worse (area squared) and combined with the longer lamp which will create greater convection currents in the arc tube, is likely to mean that the U bend may not get hot enough for full vapouristaion.

There is also the risk that on non dimple arc tubes, the sodium will migrate entirely to the U bend and that on starting, the heat loss may exceed that generated by the neon meaning that vapourisation will never occur.

Running cap down, will make it even worse for heat loss and the risk of sodium contamination of the electrodes - more metal in the bigger lamps.


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 Post subject: Re: SOX lamps
PostPosted: Tue Apr 07, 2015 8:47 am 
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Ok so heat loss is a bigger problem than I thought. Considered the fatter arc tubes but not being very good at math I forgot to consider that the marginally fatter visual appearance equalled an actually much larger than is apparent area. The sodium distribution in my two 135 watt'ers is very good along the tube so I won't be trying this, then.

Philips do state, somewhere on their website, that their smaller 55W and under lamps are universal burn *if* the luminaire is in a shock free environment (so, not road lighting). It bothers me because a) I now can't find this reference and b) it goes against what is commonly known about them! Unless by universal they somehow don't mean all positions including cap down...

If I can find it again I'll post it here, because I swear I'm not going mad.


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