Discharge lighting fault finding

[jimmer]

On an installation of Metal halide low bays that i fitted a few years ago, some of the fitting are going on and off during the day. Some times they are off for hours. The installation does have heavy industrial machines so voltage spikes on start up or full load could have an effect but i would only expect this to knock out a fitting fo 10 minutes or so. Is it an ignighter issue?
Any help much appreciated

 

[MarcT]

It does sound more like a lamp issue, especially if the lamps are more than about 18 months old. even when a full relamp is done there can be some massive variations in lamps from the same batch. This seems to be more apparent with halides than sodium for some reason. Some ballasts can be more sensitive to voltage than others as well, although this tends to be less common than the ignitor/lamps faults. What i've found usually with ignitors is they they either don't strike at all or the lamp doesn't get to full brightness. if it was a brown-out issue i would expect to see more than a few fittings drop out.

hope this helps