electrically operated, mechanically held contactor

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izak

Senior Member
Location
Springfield, MO
I have got a very nice, 12 pole, (6 two pole modules) GE lighting contactor that was given to me, and I am a little wary of how exactly to set it up.

I know it sounds funny, but I am going to use it to control all my exterior lighting on my home, which at this time consists of 3 separate 'legs' if not circuits.

I am going to control it with a digital TORK timeclock, using both its time functions, and digital photocell control.

My problem is this: I understand that when I energize the coil, the mechanical holding mechanism will activate, and I assume that I will need another momentary signal to release the 'hold' at my 'off' event.

My time clock is programmable to provide 'on' or 'off' events, but they are not momentary. I know that I can electrically hold this coil with the timeclock for the duration of the 'on' cycle, but I am at a loss as how to provide the momentary signal for the 'off' event.

In the past, we have often removed the latching device on a latched contactor, -as It was a physically separate device- and simply held the coil electrically for the entire 'on' duration. (which gets noisy sometimes)
But this contactor doesnt easily allow that type of modification, and I would like to use it as it was intended to be used.

Would anyone care to guide me on the proper setup for what I am trying to achieve?

thanks

Izak
 

iwire

Moderator
Staff member
Location
Massachusetts
Have your controls control the coil voltage to a double throw relay, and wire the normally closed contact to send the 'open' signal to the contactor and the normally open contact to send the 'close' signal to the contactor.

Make sure that the contactor has it's own internal contacts that kill the power to the contactor coils once the contactor has latched.
 
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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
An option is to make a timer using a DC source and relay, and placing an electrolytic capacitor in series with the relay coil. The relay coil will drop out when the cap has charged. The time depends on the cap value and the coil current.
 
Location
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EC - retired
Come on use your imagination. Time delay ice cube relays can have many different settings. Single shot. TDON. TD off. Recycle. Use time clock to initiate a single shot timer set for .25 seconds. Open contacts and do it again xxxhrs later. A little more involved with photo cell but entirely doable. I like Pico controllers for this kind d of stuff.
 

iwire

Moderator
Staff member
Location
Massachusetts
Come on use your imagination. Time delay ice cube relays can have many different settings.

Yes, they can have many.

But here is what I see.

He has a time clock which basically provides a single dry contact that is either open or closed.

He has a contactor that has two coils, one has to be powered on while the other is off to close the contactor and that has to flip flop when he wants the contactor to open.

These inputs to the contactor can be pulse or continuous but cannot be both on at the same time.

So yes we might be able to use a TDR but it would have to be double throw or you would still have to add a DT pilot relay.

Lets not make the easy complicated, a single inexpensive SPDT relay will do the job.

You could use certainly add a TDR to the circuit but it would not be needed.
 

Thedroid

Member
Wow I've never seen a small contactor that had opening and closing coils. Just the really big ones.

Guess I haven't been around long enough.

Do you have the model number of said contactor?
 

Thedroid

Member
Well a simple google search turned up a whole bunch. I don't do a whole lot of lighting.

Should be a standard way to control these. Seems like most would be photocell, timer, motion detector.
 
Have your controls control the coil voltage to a double throw relay, and wire the normally closed contact to send the 'open' signal to the contactor and the normally open contact to send the 'close' signal to the contactor.

Make sure that the contactor has it's own internal contacts that kill the power to the contactor coils once the contactor has latched.

That's the ticket. The de-energization of the coil is normally done through the contactors auxiliary contacts; the CLOSE is wired through a NC and the OPEN is wired though the NO contacts to the coil. (The best thing though - and GE is pretty good about it - is to search the GE website for the wiring diagram based on the catalog no. of your device.)
 
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Bob mention two coils

Its been a few years since I worked on one couldn't remember if the control was two wire or three
I googled it and come up with this diagram, been working on it most of the day.


http://home.comcast.net/~ronaldrc/wsb/Mechandically%20held%20lighting%20contactor/a.htm

Maybe this will help to adapt a relay to it.

I hope I have my contacts in the right sequence?

Separate opening and closing solenoids are usually found on MV circuit breakers. Lighting contactors are normally have a single solenoid.
 

izak

Senior Member
Location
Springfield, MO
the last small SquareD lighing contactor i dealt with had an accessory mechanical latching component with a separate unlatching coil. we dealt with That problem simply removing it.
this was for 480 volts on down.

Honestly, I really appreciate Everyone chiming in, a TD relay set for one-shot was sort of where my brain was headed, however it will involve another set of contacts, and I love a simple solution.
so thank you, BOB for your simple solution, I do believe it has separate coils, and it does have auxiliary contacts, both NC and NO, I believe, so I think that i can make that work.


I was REALLY interested in the DC concept with the capacitor, but I dont have another DC power source (what ive got is currently running one surveilance camera for the front of the house, which is tied into the TV. -we call it the Driveway Channel-)


Thank you
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
the last small SquareD lighing contactor i dealt with had an accessory mechanical latching component with a separate unlatching coil. we dealt with That problem simply removing it.
this was for 480 volts on down.

Honestly, I really appreciate Everyone chiming in, a TD relay set for one-shot was sort of where my brain was headed, however it will involve another set of contacts, and I love a simple solution.
so thank you, BOB for your simple solution, I do believe it has separate coils, and it does have auxiliary contacts, both NC and NO, I believe, so I think that i can make that work.


I was REALLY interested in the DC concept with the capacitor, but I dont have another DC power source (what ive got is currently running one surveilance camera for the front of the house, which is tied into the TV. -we call it the Driveway Channel-)


Thank you

Do not remove the latching mechanism or the unlatch coil, The coils used in latching contactors are not rated for continous duty and will have a short life if used as continous duty. You mentioned it is a GE, certain models of GE contactors have only one coil, it is momentarily energized to latch, then energized again to unlatch. these will have a timer module built in to accomplish this. They also have a two wire module that is an option for use with two wire control schemes such as time clocks. The problem with those is they also require a 24 hour hot also. As iwire said using a double throw relay would be the easiest route, if the contactor has the three wire control module installed, if it has the two wire module, the relay will not be needed.
 
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