Motion sensors less efficient than leaving the lights on?

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Hello all,

Our office has a frequently-used corridor, with motion sensor controlled fluorescent lighting - 36W 5ft sylvania tubes, 4 to a fitting, 6 fittings in total. They switch off after about 30 secs, to be fired back up seconds later by the next passer-by.

Might be a question with no straight answer, but (say) how many units of juice would be used on 120 start-up and 30 sec cycles (1 hrs worth), compared to 1hr of continuous running?

Thanks in anticipation :)
 
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It would depend if they are Switchstart or High frequency.

When they strike do they glow and come on gradually, or flash on/ off a couple of times then come on.
 
Many thanks for your rapid response.

@Rocky - I think "strike, then flicker a bit, then come on" type. They don't look noticeably different to any fluoro start up I've even seen. (I guess your second option is noticeably different, even when not taking notice)?
 
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If I have got my sums right, I come to the conclusion that if the lights were left on for the total hour, you would use something like 1Kw
and if the lights were switched on for half that time,
but operated 120 times, you would use about 0.57Kw.
 
Our office has a frequently-used corridor, with motion sensor controlled fluorescent lighting - 36W 5ft sylvania tubes, 4 to a fitting, 6 fittings in total. They switch off after about 30 secs, to be fired back up seconds later by the next passer-by. Might be a question with no straight answer, but (say) how many units of juice would be used on 120 start-up and 30 sec cycles (1 hrs worth), compared to 1hr of continuous running?
It sounds intuitively like a strange setup for a frequently-used corridor in an office - don't the lights end up being on for most of the working day?

I would have guessed that tube lifetime was far more of an issue than electricity usage. The link provided by Alarm suggests that fluorescent tubes may die after about 6,667 'starts'. If you really did have 120 starts per hour for 8 hours per day (which I'm sure is more extreme than the reality!), that seems to work out at a tube life of just under 7 days! Admittedly, I'm sure that's far more extreme a situation than you have, but I still would have expected that your tubes would have a far shorther life than if they were on for the whole working day - any idea how long they tend to last?

Kind Regards, John.
 
It'd make more sense to set the delay to something higher than 30 seconds. If the corridor is as busy as you say, there's really no need to be turning the lighting off only for it to be switched on again 5 seconds later. I'm with John on this one - it can't be good for the life of the tubes or the fittings themselves.
 

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