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 Post subject: Electronic ballasts
PostPosted: Sun Dec 27, 2009 10:01 pm 
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As I have mentioned before I am not a great fan of electronic gear primarily due to them not being as reliable as magnetic gear and also the fact that their production costs and production miles probably do not offset their assumed power savings.

This afternoon I did some experimentation with a 2003 SELC 70w SON/MH ballast as used in an Urbis ZXU1.

The ballast incorporates a minicell on flying leads so is an "all in one" gear package for a lantern. It can also be dimmed, but this particular unit did not have that option.

I have 2 of these ballasts but the other is duff... I also have a duff electronic ballast from Mazeteam and also another Philips duff ballast for a 35w SOX lamp. Hmm as I was saying about reliability...

Anyway is it more efficient than a magnetic ballast? For comparison a good low loss magnetic ballast running a 70w lamp should be around 85w total circuit power.

The SELC initially ran the lamp at total power of 35w. It held the lamp at this rating for around 3 or so minutes (presumably to warm up the lamp slowly and hence prolong life). It then gradually increased the power about 2-3w at a time over a period of about another couple of minutes until full power was reached. Total circuit power was 90w for one lamp and 88w for another. So no power saving then....


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 Post subject: Re: Electronic ballasts
PostPosted: Mon Dec 28, 2009 1:30 am 
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You would think councils would stop ordering these when they see how unreliable they are. Throw in the element of how expensive they are to buy and magnetic gear seems like a much better option. Now you're saying they don't even save any power, in other words they're a complete waste of money!

It's a bit like how councils are ordering LED lanterns left, right and centre even though they're dearer than CFL lanterns, the light output is much worse and the entire lantern has to be replaced after six years approx when CFL lanterns could last 30 years or more before they need replacing! Madness!  :evil:


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 Post subject: Re: Electronic ballasts
PostPosted: Mon Dec 28, 2009 9:45 am 
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Correct. The electronic ballast would have been a lot more expensive. Judging by how many end up in the scrap bin, they are a lot more unreliable. Then we find out that a ballast that still works is actually less efficient than a traditional ballast. And then there was the loud buzzing noise, which was on a par with traditional ballasts that have given 40 years service.

Just to add to the debate, the Harvard ballast in my 70w CDM ZX1 consumes a total of 84w, if I remember correctly, which is no more efficient than traditional ballasts. I definitely remember being surprised at the lack of power saving.


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 Post subject: Re: Electronic ballasts
PostPosted: Mon Dec 28, 2009 10:04 am 
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The only electronic ballasts that I have measured for power consumption and have actually shown a saving have been for fluorescent (PL-L) lamps. SON and SOX electronic ballasts seem to offer no power saving over magnetic - which with proper design shouldn't be the case. However an "efficient" electronic ballast will cost a lot more to design and build than a run of the mill design.

I have magnetic ballasts which are 50 and somecases 60 years old. They have been in damp column bases, have been frozen during the winter and cooked during the summer. They may not be as efficient as a moderm magnetic ballast but they still work.

Electronic ballasts tend to be in the relatively "more sheltered" environment of the lantern enclosure and whilst this may only be IP44 rated rather than the fully sealed IP65/66 rating of the optics, it is still far kinder than in the bottom of the column. Yet reliability is still poor in comparison to magnetic gear.


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 Post subject: Re: Electronic ballasts
PostPosted: Tue Dec 29, 2009 12:44 am 
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The Holophane QSM's in York used Harvard electronic gear (as you'll well know, phosco, as that one I gave you was from a QSM!) and there were serious reliability issues. Fortunately for the QSM's where the gear fails, AMEY now can get different ballast which (I'm told) are far more reliable. This may explain why a few more QSM's have popped up in the latter part of this year...

But it's the electronic fluorescent ballasts which are the most reliable. Soon, all the outbuildings here at home (I have 2 to fit in the cabin) will be lit by box lights with electronic gear... they've seen a year in service and none have failed - which is more than could have been said if they were powered by Harvard SON ballasts!

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 Post subject: Re: Electronic ballasts
PostPosted: Tue Dec 29, 2009 8:27 am 
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Electronic ballasts for fluorescent lamps have been around for over 25 years now - I'm talking for the 4/5ft type T8 tubes rather than CFL, but even those are getting on for 20 years now since they 1st came out. Generally they seem to be very reliable in "office service". Even where I have had CFLs going back to the early 90s, its the tube which goes first or occasionaly the main smoothing capacitor (which is easy to change) rather than the drive electronics.

However streetlighting ballasts don't seem to match that reliability - it can't all be down to the environment - which you can easily (and should) design for anyway.


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 Post subject: Re: Electronic ballasts
PostPosted: Mon Feb 01, 2010 9:41 pm 
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It appears that Philips must now be allowing other manufacturers to licence produce Cosmopolis electronic ballasts.


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 Post subject: Re: Electronic ballasts
PostPosted: Tue Jan 10, 2012 8:47 pm 
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Last night there were some power fluctuations in my local area. At least three times the power went off for a split second, which caused a noticeable 'dip' with the lighting in the house and also caused mains powered alarm clocks to reset and the desktop PC and televisions to switch off.

This morning, when driving to work I noticed that 10 lanterns on my route through the village were not working. Some were Iridiums, some were ZX3s, some were ZX1s. The only thing they had in common was that they run SON lamps and have electronic control gear. No SOX, CFL or electromagnetic geared SON lanterns appeared to be affected. It seemed as if the power fluctuations had knocked the lanterns out for the rest of the night. This evening all of the lanterns were lit up. Perhaps there is some form of built in safety device that kills the lamp for the night if there are power fluctuations to protect the ballast from failure or something. Any ideas?


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 Post subject: Re: Electronic ballasts
PostPosted: Tue Jan 10, 2012 9:11 pm 
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Could be either the gear or the RF node if fitted, being upset by the variations. Given Hampshire use electronic conventional NEMAs as well, they could have also been affected. I doubt it is safety feature given that would add extra cost to protect against a relatively rare event. More likely, the power variations caused the electronics to get into an unstable state. The voltage dip may not have been enough to cause a full off.

The ZX1/3s are normally fitted with SELC electronic ballasts where as the Iridiums would be expected to have Philips gear, so if it was the gear and not the nodes/NEMAs, then it looks like even different designs from alternative manufacturers were susceptible.

The night day night cycle should have reset everything and if it was the power variations causing some of the RF nodes to misbehave, the control network should monitor that and cause a full reset - but that is probably only detected at day break or the next switch on.

I have seen similar power variations cause video and microwave oven displays do weird things.

Some SON and SOX ignitors which are designed to prevent restarts if the lamp doesn’t strike on the first attempt (hence stops flashing lamps), need the power supply to be turned off when re-lamping - if the supply is left on, the ignitor won't start the new lamp. It may have been the ignitor part of the ballast thought the power dip was a failed lamp and hence prevented a restart until the supply was properly removed. The power up sequence for a SON ignitor is different to SOX and CFL which may explain why only they were affected.


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 Post subject: Re: Electronic ballasts
PostPosted: Tue Jan 10, 2012 10:37 pm 
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Failing electronic ballasts must be a symptom of either designing too close to the limits of the components or they are just cheap and poorly made. Much higher power electronics are running in more hostile environments doing critical tasks where failure isn't good - its just a case of initial investment and design. Something that should be key in professional industrial products such as street luminaries.


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