testing my lighting setup using my timer

[jarthel]

My halide has 3 power cords (1 cable each for moonlight, T5HO and halide). I will be connecting the cables to my "timing" powerboard (has 3 sockets and all sockets are digitally controlled). Since it's only a test, the bulbs will only be turned-on for 5 minutes only.

The sequence will be:
1. T5
2. halide
3. moonlight

I somehow recall that it is not advisable to test halides this way. But I cannot find the discussion/article again.

can you please help?

thank you

 

[dw1305]

Hi all,
Should be all right, if you them on and them turn them off again. The problem is that discharge lights (like metal halides, don't re-strike very well, so often they have a built in time lag to stop you trying to re-strike them whilst they are hot.
They are best in situations where they come on and then stay on for several hours before going off and staying off until they are fully cool (you can't use them with a photoelectic cell for example).

cheers Darrel

 

[jarthel]

thank you

Hi all,
Should be all right, if you them on and them turn them off again. The problem is that discharge lights (like metal halides, don't re-strike very well, so often they have a built in time lag to stop you trying to re-strike them whilst they are hot.
They are best in situations where they come on and then stay on for several hours before going off and staying off until they are fully cool (you can't use them with a photoelectic cell for example).

cheers Darrel

 

[Iliveinazoo]

Many street lights use metal halide lamps switched via a photoelectric cell. However it is true that you shouldn't switch them on and off rapidly as it will greatly reduce their life expectancy.

 

[dw1305]

Hi all,
It's just the re-strike that is a problem, so a photoelectric cell for streetlights is fine, because you can set it to come on at a very low light level, so once it's on it stays on. The problem comes when you want to use them as supplementary grow-lights, because if you don't get the setting right, clouds etc can trigger them and this shortens the life of both lights and ballasts. Magnetic ballasts are less efficient but last almost eternally, I've got Son T luminaire ballasts that are over 15 years old and have run for 100,000's of hours and are still working.
cheers Darrel