Hi I've been wondering that obviously there is SON-T street lighting which use electronic ballasts- particularly the newish iridium 1 lanterns that have a slimmer canopy and are in an olive green colour. I've seen them being erected in the Basingstoke town, which is a neighbour town to Reading.

From what I notice of these new olive green slim looking iridiums (yes them classic shoe shaped lanterns  ) have SON-T bulbs that cast a deep amber gold yellow colour which is not very far off from the SOX ish colour. Could it be the use of electronic ballasts on SON-T bulbs or is it a certain HPS lamp maker that make them to have a deep gold amber colour.

I've looked at the iridiums installed on that road that replaced a LED conversion (good thing) that are the usual white colour with a bigger or bulgier canopy and the light they give off is a bright orangish white colour (not pinkish white associated with mercury loss cos they're newly installed) and I thought the magnetic ballasts are supplying the ideal power to the SON-T bulbs and the electronic ballasts in the Basingstoke green iridiums are under driving them SON-T lamps and I thought this is how energy saving with HPS electronic ballast lanterns work, by underdriving the lamp

If these HPS are dimmed at midnight, they would cool down to a SOX colour. Otherwise, they have the same colour as the magnetically ballasted SONs.
Here is a video of a 100W HPS lamp on an Eltam electronic ballast.

Hi I've been wondering that obviously there is SON-T street lighting which use electronic ballasts- particularly the newish iridium 1 lanterns that have a slimmer canopy and are in an olive green colour. I've seen them being erected in the Basingstoke town, which is a neighbour town to Reading.

From what I notice of these new olive green slim looking iridiums (yes them classic shoe shaped lanterns  ) have SON-T bulbs that cast a deep amber gold yellow colour which is not very far off from the SOX ish colour. Could it be the use of electronic ballasts on SON-T bulbs or is it a certain HPS lamp maker that make them to have a deep gold amber colour.

I've looked at the iridiums installed on that road that replaced a LED conversion (good thing) that are the usual white colour with a bigger or bulgier canopy and the light they give off is a bright orangish white colour (not pinkish white associated with mercury loss cos they're newly installed) and I thought the magnetic ballasts are supplying the ideal power to the SON-T bulbs and the electronic ballasts in the Basingstoke green iridiums are under driving them SON-T lamps and I thought this is how energy saving with HPS electronic ballast lanterns work, by underdriving the lamp

Quite possible that they choosed the wrong lamp like a 70W SON-T on 50W tap...?
Here it happens sometimes when some stupid electricians choose lamps with higher wattage without changing the tap on the ballast!
So they finally they emit a deep orange colour.

Hi dor123 and MF yes I think its mostly due to the electricians using 70W lamps on 50W max lanterns- they think under driving a higher wattage lamp will save energy  well well well that is completely utter nonsense to just do that really. The poor ballasts are indeed taking the strain if they are trying to fully light a lamp higher than the ballast's stated wattage, especially electronic ones. I think I've saw a few of these Iridiums in Basingstoke fail.

But if the electricians have done a proper job with lamps, they may as well have dimming ballasts enabled

Most electronic ballasts shuts down when there is a mismatch between the lamp wattage and the ballast wattage.

Especially Philips electronic ballast???

Maybe the thing is something to with the manufacturer of the HPS lamps, they're probably designed to give out a low colour temperature, casting a golden amber colour (2200K) the ones used in Basingstoke streetlights, and most HPS streetlights in Reading use HPS lamps that cast a higher colour temperature for HPS (2300-2350K)

Most electronic ballasts shuts down when there is a mismatch between the lamp wattage and the ballast wattage.

They are not that much selective and identifying lamps is even not the purpose of that.
The circuit behind looks for failing cathodes - so either rectification, or too high arc voltage drop.
The second may trigger when you put a higher arc voltage lamp onto a ballast designed for lower arc voltage, but the extra voltage would have to be 60V or more, so for most small fluorescent at least double the arc voltage.
And there is usually no detection for an arc voltage being lower than designed.
The thing is, the concept does not expect a wrong lamp vs ballast combination. The concept is supposed to detect just failures of the lamps of the correct type.

And because the arc voltage specification of practically all lamps is a result of compromise between efficacy (too low arc voltage makes the non luminous 15V electrode drop losses too significant). not too high (ballast design complications, leading to more expensive and less efficient ballasts) and manufacturing economy (as much as possible common parts and tooling among products), the arc voltage of most lamps have settled between about 40..100V.
(well, there are exceptions, but these are either high runners optimized for efficacy like F32T8 or specialties, like F4T5 sharing everything except length with other other miniature t5's).
That means most unmatched combination will light up the lamp, including the ones causing overloading or too much stress for either the lamp or ballast components, leading to bad reliability or short life of either part or even safety problems.

The PIA Plus, have yellower color than standard HPS lamps, as it have less mercury.