Soft start lighting timer/ controller?..

Anyone here know if one of these exists?.

We have a job to do to control some lights, in essence similar to the PIR operated light in your front garden except that this is Six separate lights around 2 kW in total load.

The lights are in shall we say, very awkward locations and are a PITA to get to. It seems to me that if we under run them a bit then their lifetime before replacement might be extended. There is a fair old bit of cable run in this too so its prolly going to loose a bit anyway;)..

What also seems like a good idea is to soft start them i.e. just fade up the volts applied over a second or so to reduce the switch on surge when cold.

We have a simple infra red light beam detector arrangement that will give a contact closure when triggered which we could interpose another relay to source volts to the larger relay. If that one could accept either a simple contact close or volts applied say 12 to 24 then fine.

If it can also stay switched on for a time period perhaps a minute or so then better still.

TIA.

Reply to
tony sayer
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As said its hard to make much progress until you tell us what type of lights these are, as different types respond to different approaches.

I don't know whether you've already taken a step back and picked the best suited lamp type, 2kW is an unusually high wattage if you have. Sometimes its useful to use an overlapping lighting area layout that's tolerant of dead lamps. Switching them separately or in smaller groups can maximise lamp life. There are also other possible aprpoaches, if you want to tell us more about the situation.

NT

Reply to
NT

In article , tony sayer writes

For quick & dirty, how about an inrush current limiter (NTC thermistor)?

A quick search pulled up this:

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farnell part numbers.

I've tended to avoid them in that past as I've never thought that hot running components go hand in hand with reliability but if it works for you then fine. The size chosen and a ventilated box could control your time constants.

Reply to
fred

This got posted in the wrong thread earlier;!..

The 2 kW is the total load made up of a number of 500 watt bulbs spaced out over the area..

And the way the wiring has to run and its partly installed they are not separable as such..

Yes standard security filament lights like the sort used in PIR operated ones like as used on the front of your house...

like these ones..

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Reply to
tony sayer

good candidates for udnerrunning slightly to further improve life - albeit at the expense of significantly icnreased power consumption per given light output.

However... linear halogen isn't often a good option nowadays. You're looking at terrible run costs, plus lamp life in the 1500hr region, or upto 4000hr at best. Without knowing anything much about the install, its hard to say what's best, so being general...

CFL is good if you dont need as much light, or dont mind putting mroe fittings up, and the lights are being used for short periods, ie for access lighting. 50 or 60 lm/w.

HID is much more efficient, ie cheaper to run, but has more upfront cost, and the lamps can occasionlly explode. Good for industrial situations.

Linear fl is still an option outdoors, and suits mounting on the soffits. Electronic ballast fittings will give you 20,000hr lamp life, and good choice of tube can get you over 100lm/w.

Low pressure sodium is sometimes a better bet. They deliver a pure yellow lgiht only, with 9 minute warm up time, so need to be on a photocell, not PIR.

If you really must stay with the halogen fittings, and are prepared for the resulting bills, bear in mind that these lamps take about 10x rated current during startup, so you'd need a PIR able to start a 20kW load.

Starting halogens in series pairs for a second or so is enough to prolong their life, and will reduce peak on current to that of a 5kW load.

NT

Reply to
NT

Or replace with 10W LED - they may not be as "bright" but they give a surprisingly good light

Reply to
John

As I said over in the other thread, without having to rewire the lights, if you popped a diode in series for the soft start condition, that would give you half volts. Some heaters use that method to give stepped control.

Chris

Reply to
Chris J Dixon

In article , John scribeth thus

Yes replaced the one here with one of they, very low amount of light in comparison and it only lasted three months;(

Reply to
tony sayer
I

Someone else is paying that bill.

Too long in this case.. And we need a white light too..

Might be able to do that..

Thanks for that .. all noted:)...

Reply to
tony sayer

Noted:)..

Reply to
tony sayer

If you used 1 diode on the lot, you've still got the 20kW start issue. If you put half on a diode facing one way, and the other half on a diode facing the other way, then you get 10kW starting load.

NT

Reply to
NT

3 months is not bad for a LED!
Reply to
ARWadsworth

You'd need a two pole relay to bypass them, though. It would help the power factor while starting, though.

Another problem with the diode solution might be finding an 80A, 500V rectifier diode.

Reply to
John Williamson

You could always build one out of stone jars, 1920s style :) I'd much prefer to use the 2 poles to switch the lamps from series to parallel.

NT

Reply to
NT

Soz .. it was a low consumption fluorescent shaped to fit that space. The reason it was low consumption was that there was piss poor light output;!..

Reply to
tony sayer

Around 11 quid on RSWWW some 100 amps and 1500 PIV ....

Reply to
tony sayer

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