lighting control,contactors
- Thread starter rbarbrey
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bphgravity
Senior Member
- Location
- Florida
Re: lighting control,contactors
The items you list are all means of convienent control of equipment. Lets say for example, you want to have three 20-ampere, 277V circuits to all come on at the same time from one control point. An easy way to accomplish this is to install a remote 120V switch that energizes a 120V coil of a contactor. The 3=pole contactor switches the three loads.
What are the benefits of this installation? One, this allows your control circuit to be safer at 120V circuit verses a 277V circuit. The point of control switches no load other than minimal coil load and multple larger loads can be switched at the same time with standard devices and minimal wiring.
I hope this answers some of your questions? I'm not exactly sure what you are having an issue with?
The items you list are all means of convienent control of equipment. Lets say for example, you want to have three 20-ampere, 277V circuits to all come on at the same time from one control point. An easy way to accomplish this is to install a remote 120V switch that energizes a 120V coil of a contactor. The 3=pole contactor switches the three loads.
What are the benefits of this installation? One, this allows your control circuit to be safer at 120V circuit verses a 277V circuit. The point of control switches no load other than minimal coil load and multple larger loads can be switched at the same time with standard devices and minimal wiring.
I hope this answers some of your questions? I'm not exactly sure what you are having an issue with?
Re: lighting control,contactors
Thanks, but I know how a coil and controls operates, my question is coil volage is only 120v, the coil only controls the coil and not the actual load voltage. in other words, the coil does not provide voltage for the lights? Is this correct? Thanks
Thanks, but I know how a coil and controls operates, my question is coil volage is only 120v, the coil only controls the coil and not the actual load voltage. in other words, the coil does not provide voltage for the lights? Is this correct? Thanks
Re: lighting control,contactors
as with Bryan, I'm not sure I understand the question, but for reference, in this area, the signs/outdoor lighting are often controlled thru a contactor that is controlled by a time clock/photocell arrangement with the two wired is series.
The power for the contactor coil originates with the photocell, so the contactor will turn on at dark, and it series wired thru the timer contacts so the custmer can have the lighting turn off before daylight, if desired.
The time clock motor is wired to line voltage.
as with Bryan, I'm not sure I understand the question, but for reference, in this area, the signs/outdoor lighting are often controlled thru a contactor that is controlled by a time clock/photocell arrangement with the two wired is series.
The power for the contactor coil originates with the photocell, so the contactor will turn on at dark, and it series wired thru the timer contacts so the custmer can have the lighting turn off before daylight, if desired.
The time clock motor is wired to line voltage.
Re: lighting control,contactors
Right, the only load on the control (120v) switch is the coil, which is tiny. Once the coil is energized, it closes the contactor. The "switch legs" are wired line and load into the contactor, with the line constantly "hot", and the load only becoming "hot" after the coil is energized.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: lighting control,contactors
To add to this extremely informative thread:
Make sure you have constant power to the photo cell first then run through the timer contacts then to the coil, as if the timer switch's the photo cell then the lights will turn on for a few minutes every time the timer turns on. Clock motor on the timer also has to have constant power.
In other words run a hot and neutral to the timer motor then to the photo cell, photo cell's red switch leg then goes through the timer contacts on to the coil of the lighting contactor.
To add to this extremely informative thread:
Make sure you have constant power to the photo cell first then run through the timer contacts then to the coil, as if the timer switch's the photo cell then the lights will turn on for a few minutes every time the timer turns on. Clock motor on the timer also has to have constant power.
In other words run a hot and neutral to the timer motor then to the photo cell, photo cell's red switch leg then goes through the timer contacts on to the coil of the lighting contactor.
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