Lighting contactors
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Ed MacLaren
Senior Member
Re: Lighting contactors
The power contacts are driven to both the open and closed positions by a momentary pulse of control power, therefore they are quieter than magnetically-held contactors because there is no continuous AC hum.
Mechanically-held contactors do not "drop out", and switch off the lighting during control power failures. During such failures, magnetically-held contactors usually drop into the "off" position, even though service voltage may still be available.
Ed
[ January 03, 2005, 06:56 PM: Message edited by: Ed MacLaren ]
The power contacts are driven to both the open and closed positions by a momentary pulse of control power, therefore they are quieter than magnetically-held contactors because there is no continuous AC hum.
Mechanically-held contactors do not "drop out", and switch off the lighting during control power failures. During such failures, magnetically-held contactors usually drop into the "off" position, even though service voltage may still be available.
Ed
[ January 03, 2005, 06:56 PM: Message edited by: Ed MacLaren ]
Re: Lighting contactors
The "classic" example of a mechanically-held contactor (latching contactor), is in a library where is is very quiet & you want to eliminate the possibility of hearing the alternating current hum of an energized coil.
There are of course, other applications.
The "classic" example of a mechanically-held contactor (latching contactor), is in a library where is is very quiet & you want to eliminate the possibility of hearing the alternating current hum of an energized coil.
There are of course, other applications.
aelectricalman
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Re: Lighting contactors
if changing out bulbs for better designed versions does not fix a problem with humming in a dimmer switch, can contactors help eliminate the loud noise. Note, I've tried 3 types of dimmers now, none help the cause. Just curious if this is something viable or is there another option. I/ve had to use contactors once for a photo cell, but not sure of its application beyond this.
if changing out bulbs for better designed versions does not fix a problem with humming in a dimmer switch, can contactors help eliminate the loud noise. Note, I've tried 3 types of dimmers now, none help the cause. Just curious if this is something viable or is there another option. I/ve had to use contactors once for a photo cell, but not sure of its application beyond this.
Re: Lighting contactors
Don't see why a dimmer would generate audible noise except in the lamp itself unless the RF filter inductor is humming?
And, I wonder if the proximity of the filament to ferrous materials makes the filament vibrate more.
I also speculate that these vibrating filaments might fail prematurely.
But why a contactor, why not just replace the dimmer with a switch?
[ January 07, 2005, 12:45 AM: Message edited by: rattus ]
Don't see why a dimmer would generate audible noise except in the lamp itself unless the RF filter inductor is humming?
And, I wonder if the proximity of the filament to ferrous materials makes the filament vibrate more.
I also speculate that these vibrating filaments might fail prematurely.
But why a contactor, why not just replace the dimmer with a switch?
[ January 07, 2005, 12:45 AM: Message edited by: rattus ]
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