A building owner wants me to look for a cheap way to have 4 circuits worth of outdoor lighting come on at dusk (without having to change timeclock setting throughout the year)and off at midnight.
I already have a photo eye controlling a 4-pole contactor. Now he wants to add a timeclock to have the light turn off at midnight. No problem, but I mentioned that the timeclock will have to be set to click back on at some point during the day to reactivate the photeye. That will kick the building lights back on for a few minutes, then shut them back off after the photoeye resets. Is there a simple way to avoid this with basic, readily available parts?
Sure, Control leg to photo first, then to time clock contactor then to four pole.... Your photo cell is going to see power all the time and either let power through to the clock or not. It won't lose power and go into a short time reset turning the lights on at all. Ya got everything ya need. Just tell him you added a resistifractometer for free to fix the issue.
Re: lighting control ideas anyone?#45810 12/07/0406:47 PM12/07/0406:47 PM
Okay, good solution. I origianlly disregarded that idea because then the time on the timeclock would stop during the day when the photocell went off. But after seeing the idea agin on screen...... I'll just get a 2-pole timer and feed the clock off the hot. I'm used to Intermatic T-101 & T-103.
Thanks for the brainstorm Kent!
Re: lighting control ideas anyone?#45811 12/07/0406:57 PM12/07/0406:57 PM
I guess I could do that too. I don't have to worry about UL (making an alteration to a listed product like that)? It would involve pulling the fork out from underneath the screw, clipping the fork off and splicing the short 18awg to the hot. Will that pass inspection? Or else find a brand that allows a seperate clock feed? Or else spend the extra $25 on the 2-pole?
Re: lighting control ideas anyone?#45813 12/07/0409:56 PM12/07/0409:56 PM
Maybe I'm reading this wrong, but why don't you feed the timeclock, set to go off at midnight and come on at noon. After the timeclock feed the photocell and have it feed the lights. The lights will come on at dusk based on the photcell and go off at midnight with the timer.
Re: lighting control ideas anyone?#45814 12/07/0410:24 PM12/07/0410:24 PM
No sweat EE, it's easy to miss. the problem doing it the way you describe (and I have done in the past) is that at noon, when the timeclock turns back on, it will power the photoeye which (as far as all my photoeye experience has shown) will cycle on for a few minutes, then kick back off. Not a big deal, which is why I was looking for a simple solution to avoid the lights kicking on (seemingly) for no good reason in the middle of the day.
Re: lighting control ideas anyone?#45815 12/08/0412:12 AM12/08/0412:12 AM
They make what is called an "Astronomical" time clock for this. And it used to be that the only ones were expenive high tech jobs. Wait they still are. Mechanical, and there is an electronic version. http://www.intermatic.com/?action=subcat&sid=92
Piece of cake. Tork (as well as a few others) has 1 & 2 pole timeclocks that have astrological settings built in. They compensate for the sunset/rise every day. You can modify it to +/- up to 2 hr of that time. They also do DST. They're a bit of a nuisance to program but are dummy proof once you set them up. Even have 9v battery for backup. We have about 30 of these in our system. Many of ours are set up just as EE said; clock feeds cell so it comes on at dusk and clock kills power at midnite. The rest of them we eliminate the cell and use the astrological feature to turn on the contactor 30 min before sunset and off about 11 or 12.
Re: lighting control ideas anyone?#45817 12/08/0410:49 AM12/08/0410:49 AM
OK, Dunno, Your customer wants it done "cheap". Sure a astronomical clock would be one way to go but astronomical clocks are pricey. To clarify, both tork and intermatic cheapy 24hr clocks can be fed with one feed for both the motor and contactor OR pull the jumper and feed the motor and contactor separate. (See above link.)
Edit; My link did not work as I expected. You will need to hit "wire diagrams" for the first (cheapest) clock on the list.
[This message has been edited by kentvw (edited 12-08-2004).]