John Rumm wrote:

On 03/11/2011 12:30, tony sayer wrote:

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

What about step starting? Fire up the lights in series pairs, and then a
couple of secs later hit them with full volts? Just need a couple of
relays and a simple timer that way.

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
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.