J
John
- Jan 1, 1970
- 0
Here,s an odd one re CFL,s. Recently thought I,d be politically correct and
replace my Filament lamps with CFL,s throughout the house. No problems
fitting them obviously except I had to modify my ceiling fans that
incorporated lamps to suit the larger CFL,s. The next issue then was that
some of the CFL,s glowed very dimly, not noticable during the day. Also,
some CFLs would periodically ( 15 seconds or so, very regular) give a small
flash. Again not noticeable during the day but a nuisance at night.
Investigations showed that with the light switch OFF, the active to the
unplugged lamp had 115 volts on it. If I lifted both ends of the wire from
the switch to the lamp off, ie wire was totally floating there was still 115
volts on it!!!. If I put the incandescent back in there was 0 volts on the
active to lamp with Switch OFF.
If I put the CFL lamp back in with the switch OFF the voltage on the switch
wire or active rose over 15 seconds to around 40 volts, tube flashed,
voltage dropped to ~ 3 volts and cycle repeated again.
This is on a 240 volt,50Hz system and voltages measured with a DVM ie
almost open circuit load impedance.
What was happening was that that the switch wire from switch to lamp was a
"twin" cable ( two cables in parallel for about 15 feet) with the other
cable the active. . I can only surmise the intercable capacitance between
the active and the switch wire coupled a voltage to switch wire which
charged up the electronics in the CFL causing it to flash every 15 seconds.
Didnt happen on the Incandescent because of the far lower impedances.
Sorry to bore you, I was pi%%ed off but amazed!
John
replace my Filament lamps with CFL,s throughout the house. No problems
fitting them obviously except I had to modify my ceiling fans that
incorporated lamps to suit the larger CFL,s. The next issue then was that
some of the CFL,s glowed very dimly, not noticable during the day. Also,
some CFLs would periodically ( 15 seconds or so, very regular) give a small
flash. Again not noticeable during the day but a nuisance at night.
Investigations showed that with the light switch OFF, the active to the
unplugged lamp had 115 volts on it. If I lifted both ends of the wire from
the switch to the lamp off, ie wire was totally floating there was still 115
volts on it!!!. If I put the incandescent back in there was 0 volts on the
active to lamp with Switch OFF.
If I put the CFL lamp back in with the switch OFF the voltage on the switch
wire or active rose over 15 seconds to around 40 volts, tube flashed,
voltage dropped to ~ 3 volts and cycle repeated again.
This is on a 240 volt,50Hz system and voltages measured with a DVM ie
almost open circuit load impedance.
What was happening was that that the switch wire from switch to lamp was a
"twin" cable ( two cables in parallel for about 15 feet) with the other
cable the active. . I can only surmise the intercable capacitance between
the active and the switch wire coupled a voltage to switch wire which
charged up the electronics in the CFL causing it to flash every 15 seconds.
Didnt happen on the Incandescent because of the far lower impedances.
Sorry to bore you, I was pi%%ed off but amazed!
John