How to change to photoeye instead of time clock?

[Strathead]

not sure about the ones in this thread but ASCO 917 latching lighting contactors coils can be wired for either pulse or constant ON because they have auxiliary switches that prevent constant power from going to the coil. A twelve pole contactor can be controlled with a 3-wya switch.

The ASCO I am familiar with has an accessory called Accessory 47 that allows on/of control of a mechanical switch. That isn't what appears to be happening here though since it looks like there is an on switch leg and an off switch leg.

 

[RichB]

Ok guys-- I am getting confused here--If I read the OP correctly he wants to install a Photo cell in place of the time clock and he has the room to run conduit to the exterior--so--(bonding/grounding is assumed to be done)

Why not just run a piece of 1/2 inch to the exterior, mount a photo cell and then bring a hot/neutral to the cell and the switch leg back to one of the contactors then jump over to the other contactor --sun goes down lights come on and stay on till the sun comes up--problem solved with out the need for 2 photo cells or latching relays etc.??

Or just use a seasonal clock as was suggested, simply remove the old one and re-install the new

As you all may have guessed, I am a fan of keep it simple--so maybe I have over simplified it , but......

I'd attach a drawing but can't figure out how to :?

 

[david]

Ok guys-- I am getting confused here--If I read the OP correctly he wants to install a Photo cell in place of the time clock and he has the room to run conduit to the exterior--so--(bonding/grounding is assumed to be done)

Why not just run a piece of 1/2 inch to the exterior, mount a photo cell and then bring a hot/neutral to the cell and the switch leg back to one of the contactors then jump over to the other contactor --sun goes down lights come on and stay on till the sun comes up--problem solved with out the need for 2 photo cells or latching relays etc.??

Or just use a seasonal clock as was suggested, simply remove the old one and re-install the new

As you all may have guessed, I am a fan of keep it simple--so maybe I have over simplified it , but......

I'd attach a drawing but can't figure out how to :?

Someone paid for the latching contactor in the design, I would guess to eliminate noise in the form of chatter or humming, or perhaps to give extended life to the contactors. Not sure of the reason for the design. The OP was asking how to incorporate a photo eye control to replace the time clock in the existing control and remove the use of a time clock.

I have seen circuits that incorporate a photo eye and a time clock in series so both have to activate before energizing the lighting loads. There are lots of design choices in compensating for sunset and sunrise differentials and for cloudy overcast days that may activate night lighting (photo eye control) at undesirable hours.

I see the existing with latch and unlatch switching. Yes it can be reconfigured if the OP desires to eliminate the latching relays

 

[kwired]

If I am seeing it wrong and it is a case of latching it in and then cutting off power to coil until you give it an unlatch signal, then all you need to do to run it with a simple photocell is to drive a SPDT relay with the photo cell and have that relay give the latch/unlatch signal to the lighting contactor. NC contact is unlatch signal and NO is latch signal.

 

[david]

If I am seeing it wrong and it is a case of latching it in and then cutting off power to coil until you give it an unlatch signal, then all you need to do to run it with a simple photocell is to drive a SPDT relay with the photo cell and have that relay give the latch/unlatch signal to the lighting contactor. NC contact is unlatch signal and NO is latch signal.

Perhaps I’m rusty at this but wouldn’t the unlatch coil have constant voltage (signal) during the day light if the unlatch signal is run through the NC contacts of the relay directly to the unlatch coil for the contactor

And i will being willing to concede i am rusty at this

 

[Johnnybob]

Or just get a P/E that has BOTH n/o and n/c contacts. Normally open = latch, normally closed = un-latch

 

[david]

Or just get a P/E that has BOTH n/o and n/c contacts. Normally open = latch, normally closed = un-latch

That’s the terminology I am familiar with as well, normally open normally closed contacts, but I am being told that when dealing with photo eyes they do not refer to them as normal open and normal closed. I’m being told for photo eyes it is light on contacts and light off contacts.

I agree if on and off contacts are available in a single photo eye that will simplify the control. It has been a long time since I bought photo eyes, installed a few last year that some one else purchased, I’m not current in what the industry has to offer.

 

[david]

Or just get a P/E that has BOTH n/o and n/c contacts. Normally open = latch, normally closed = un-latch

I still am not seeing how you brake the constant control single to a latching contactor ether the latching coil or the unlatching coil unless you run the control single through the Aux. NO and NC contacts on the latching contactor

but I am rusty on control wiring and am going to leave it at that, I would use the Aux contacts to avoid a constant control single for a latching contactor that latches with a momentary single to latch, and unlatches with a momentary single to unlatch.

 

[Smart $]

That’s the terminology I am familiar with as well, normally open normally closed contacts, but I am being told that when dealing with photo eyes they do not refer to them as normal open and normal closed. I’m being told for photo eyes it is light on contacts and light off contacts.

I agree if on and off contacts are available in a single photo eye that will simplify the control. It has been a long time since I bought photo eyes, installed a few last year that some one else purchased, I’m not current in what the industry has to offer.

Standard photocells are "make" contact on darkness, "break" on light... IIRC... so that would likely be a lights on version.

I still am not seeing how you brake the constant control single to a latching contactor ether the latching coil or the unlatching coil unless you run the control single through the Aux. NO and NC contacts on the latching contactor

but I am rusty on control wiring and am going to leave it at that, I would use the Aux contacts to avoid a constant control single for a latching contactor that latches with a momentary single to latch, and unlatches with a momentary single to unlatch.

If my guess is correct, the contactor itself uses a mechanical latch... sorta like a push-button ON/OFF switch. The module below it, to which timer wires are connected, is a two-line constant signal to one-line pulse signal converter just for this purpose. It probably has integral timed-off relays to cut off the constant signal...

...but what I can't figure out is how the module knows what position the contactor is in when powered up for the first time??? Perhaps one has to set it manually if in the wrong position??? Never seen one like that before, not that I've all that many. :blink:

 

[kwired]

Perhaps I’m rusty at this but wouldn’t the unlatch coil have constant voltage (signal) during the day light if the unlatch signal is run through the NC contacts of the relay directly to the unlatch coil for the contactor

And i will being willing to concede i am rusty at this

Standard photocells are "make" contact on darkness, "break" on light... IIRC... so that would likely be a lights on version.


If my guess is correct, the contactor itself uses a mechanical latch... sorta like a push-button ON/OFF switch. The module below it, to which timer wires are connected, is a two-line constant signal to one-line pulse signal converter just for this purpose. It probably has integral timed-off relays to cut off the constant signal...

...but what I can't figure out is how the module knows what position the contactor is in when powered up for the first time??? Perhaps one has to set it manually if in the wrong position??? Never seen one like that before, not that I've all that many. :blink:

I haven't seen one either, but makes sense to me that one could design it so the coil current passes through an aux contact (may not have ready external access) that opens the circuit once the armature has pulled in and has mechanically latched, and similar for the unlatch coil, once armature has dropped out it can open the circuit to the unlatch coil and doesn't matter if you send a constant signal - coil circuit has been opened so no current is flowing through it.

Many shunt trip breakers use similar concept to keep from providing a constant current though the trip coil - once the breaker opens the trip coil circuit is also opened.

 

[mgookin]

Without power a latching relay holds the same position it had when power was last disconnected. So to answer the question of a power failure, you're at the mercy of what state it was in when the power went out, from the time the power is restored until it receives its next signal.

The benefits of latching vs. non-latching are saving the power it would otherwise require to hold the relay continuously, and elimination of noise from constantly energizing the coil.

They're at times used with a BMS.

 

[GoldDigger]

Let's acknowledge that in common usage a latching relay can be either a mechanically latching relay, the type we have been discussing, or an electrically latching relay with the latching contacts integral to the relay. The latter will not hold one if its positions when power is removed.
And a two position stepping relay is sometimes called a latching relay but has only one control input rather than separate on an off inputs.

 

[infinity]

The ASCO I am familiar with has an accessory called Accessory 47 that allows on/of control of a mechanical switch. That isn't what appears to be happening here though since it looks like there is an on switch leg and an off switch leg.

Yes, ASCO accessory #47 is for two wire control like using a single pole time clock or single pole switch, without it you can simply use a 3-way switch.

Looking at the photo's in the OP wouldn't the neutrals associated with these switched conductors need to be run into the contactor enclosure?

 

[kwired]

Looking at the photo's in the OP wouldn't the neutrals associated with these switched conductors need to be run into the contactor enclosure?

I see no real reason to run the neutrals into the enclosure. However it looks like they possibly have all the line side in one raceway and all the load side conductors in another raceway. They should have run line and load of each pole in the same raceway so their magnetic effects will cancel one another.

Add: the right contactor applies to what I said above, the left three pole contactor does have the neutral passing through - a smaller gray conductor passes through - it may that it is only associated with the orange conductor that is also similar/same size. The other larger conductors may be feeding line to line only and need no neutral?

 

[infinity]

I see no real reason to run the neutrals into the enclosure.

How do you get around 300.20(A)?

 

[Smart $]

... Looking at the photo's in the OP wouldn't the neutrals associated with these switched conductors need to be run into the contactor enclosure?

I see a red, blue, and white running from the timer to each contactor enclosure???

 

[infinity]

I see a red, blue, and white running from the timer to each contactor enclosure???

The OP said 277 volts which means the lighting circuits require a neutral. I see multiple circuits running through the contactor but no associated neutrals.

 

[Smart $]

The OP said 277 volts which means the lighting circuits require a neutral. I see multiple circuits running through the contactor but no associated neutrals.

Oh, you meant the actual lighting circuits. :slaphead:

It's okay if line and load are in same raceway, like the left side contactor... but the right side contactor does not, and that's a big no-no in Code compliance. Probably won't see much effect if the loads are fairly balanced though. Looks like the odd one (smallest orange, on rightmost contact) runs in and out through the left conduit

 

[infinity]

I didn't want to completely hijack this thread so I've continued the discussion here:

http://forums.mikeholt.com/showthread.php?t=171876&p=1674881#post1674881

 

[sparkyrick]

I see no real reason to run the neutrals into the enclosure.

A co-worker just got busted by the inspector for this. He had to go back and loop the neutrals through the enclosure to make it compliant.