I have a customer with a 100W HPS fixture on an outbuilding. The fixture is photoeye controlled. Almost everytime that a large load starts in the house (A/C, sewage ejector pump, ect.), the light shuts off and eventually comes back on.
The outbuilding and house are both on seperate loadcenters and feed from the same main panel at the meter. It appears to me that this is caused by voltage drop. Correct?? I even switch the fixture circuit to the opposite phase and it still does it. Could this be simply a photoeye problem, or utility service voltage drop???? Any suggestions?
This is in a rural area, only service on this transformer. voltage. Under start-up surge from A/C or sewage pump, I saw it drop to 112 for about 1/2 second. I switched the fixture to the "higher" phase (121) and it still dropped out under surge.
I agree with the possible loose neutral situation also. As far as the transformer, My house is the only load on a 15 KVA pole pig, it is about 60 feet from the pole to my meter, every time my 4.5 ton AC compressor starts there is a noticible flicker in the lights. Put this same load on a 10 KVA pot and it could pull down enough to turn the light out. What kind of meter did you use to measure the voltage when AC started? Most DVOMs are not fast enough to catch the dip, so it is likely the reading you got was on its way back up before your meter settled down. Just my 2 cents.
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