Hi guys.
1) Picture this circuit:
(start) 120V Supply-----20A CB-----electrically held contactor-----multiple 120V to 7500V transformers with secondary GFP-----decorative cold cathode lighting (end)
2) When the contactor closes at dusk, sometimes one of GFP's trips. Sometimes none trip. Sometimes two trip. It seems to follow no rhyme or reason. When the contactor was removed and replaced with a terminal block, the problem disappeared and the lights have been on now for over a month.
3) We were thinking the closing of the contactors initiated a high harmonic transient that tripped the GFP, but a) this has never happened with this lighting before (both per ours and the mfg's experience), and b) why would a primary-side spike cause the secondary GFP to trip?
Any thoughts would be appreciated -- thanks!
Some other considerations:
a) This installation is in a non-conditioned decorative bridge near the ocean.
b) The problems generally occurred during the winter, but cold weather shouldn't affect this.
c) I understand the primary grounding was installed and was bonded to the the sheet metal cove. It's possible there is an arc fault from the cove to the cold cathode tubing; we are investigating this.
d) This is the transformer: http://www.americancathode.com/pdf/2009_CC_TransformerLayout.pdf
1) Picture this circuit:
(start) 120V Supply-----20A CB-----electrically held contactor-----multiple 120V to 7500V transformers with secondary GFP-----decorative cold cathode lighting (end)
2) When the contactor closes at dusk, sometimes one of GFP's trips. Sometimes none trip. Sometimes two trip. It seems to follow no rhyme or reason. When the contactor was removed and replaced with a terminal block, the problem disappeared and the lights have been on now for over a month.
3) We were thinking the closing of the contactors initiated a high harmonic transient that tripped the GFP, but a) this has never happened with this lighting before (both per ours and the mfg's experience), and b) why would a primary-side spike cause the secondary GFP to trip?
Any thoughts would be appreciated -- thanks!
Some other considerations:
a) This installation is in a non-conditioned decorative bridge near the ocean.
b) The problems generally occurred during the winter, but cold weather shouldn't affect this.
c) I understand the primary grounding was installed and was bonded to the the sheet metal cove. It's possible there is an arc fault from the cove to the cold cathode tubing; we are investigating this.
d) This is the transformer: http://www.americancathode.com/pdf/2009_CC_TransformerLayout.pdf
