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Discussion Starter · #1 ·
But I'm stumped.


Scenario: 21 parking lot lights to come on at dusk and 14 of them to drop out at 12am with a manual override to turn on lights whenever needed.

I have an H.O.A, time delay relay (8-pin) and 2 contactors with N.O and N.C auxiliary contacts. This is an exam I have on Monday. I'm typically pretty good with controls so I'm a little embarrassed to ask for help. Thanks.
 

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RIP 1959-2015
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But I'm stumped.


Scenario: 21 parking lot lights to come on at dusk and 14 of them to drop out at 12am with a manual override to turn on lights whenever needed.

I have an H.O.A, time delay relay (8-pin) and 2 contactors with N.O and N.C auxiliary contacts. This is an exam I have on Monday. I'm typically pretty good with controls so I'm a little embarrassed to ask for help. Thanks.

Just when is 12 hours Anti-Meridian?

Is that like 1 hour after 11 hours Anti-Meridian?

Or is it 13 hours later?....:laughing:
 

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What's normally open and what's normally closed? :)

After 12 hours everything shouts do and begins the whole process again.

Tick, tick....
 

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RIP 1959-2015
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39,618 Posts
But I'm stumped.


Scenario: 21 parking lot lights to come on at dusk and 14 of them to drop out at 12am with a manual override to turn on lights whenever needed.

I have an H.O.A, time delay relay (8-pin) and 2 contactors with N.O and N.C auxiliary contacts. This is an exam I have on Monday. I'm typically pretty good with controls so I'm a little embarrassed to ask for help. Thanks.
Is there a time clock that shuts them off?

What is an H.O.A?

A lighting contactor on a time clock will control the 12 lights to go out at midnight

Is there a photo eye turning on all the lights at Dusk?

If so it should feed though direct to the 7 lights and the other 14 should be fed from the contactor fed from the time clock feeding the coil that closes the contacts .
 

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Discussion Starter · #8 ·
What's normally open and what's normally closed? :)

After 12 hours everything shouts do and begins the whole process again.

Tick, tick....
At dusk whatever that is. The process starts. So I have the time delay energized by my auto with the control circuit going through the normally closed contacts and to the contactor coil so when it times out at 12 am it opens contact and drops out the 14 lights. Off the same wire that hits my time delay coil I have another wire that goes to the other contactor coil so both will be energized in the auto mode just 14 will be timed out. My issue is when in hand I'm energizing my time delay again which we don't want. I need to be able to run the lights as long as I want ( all of them )
 

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Discussion Starter · #9 ·
Is there a time clock that shuts them off?

What is an H.O.A?

A lighting contactor on a time clock will control the 12 lights to go out at midnight

Is there a photo eye turning on all the lights at Dusk?

If so it should feed though direct to the 7 lights and the other 14 should be fed from the contactor fed from the time clock feeding the coil that closes the contacts .
An hoa is a hand off auto three position selector switch.
 

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Discussion Starter · #10 ·
Is there a time clock that shuts them off?

What is an H.O.A?

A lighting contactor on a time clock will control the 12 lights to go out at midnight

Is there a photo eye turning on all the lights at Dusk?

If so it should feed though direct to the 7 lights and the other 14 should be fed from the contactor fed from the time clock feeding the coil that closes the contacts .
Yeah I can wire this a couple different ways myself but part of the test is only having my select items.
 

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The 7 lights that stay on from dusk till dawn are connected to whatever device senses dark.

The 14 other lights are run through the NC contact of the time-delay, which is set to however many hours it is between dusk and 12AM. The coil of the time-delay is energized whenever the 7 lights are on.

Depending on what 'manual override' means, the hand contact will always energize the 7 lights + the other 14 on the load side of the time delay.

The auto position could be used to bypass the time delay resulting in all lights being on from dusk to dawn, or it could be connected in series with the dusk to dawn sensor resulting in normal operation in auto, no operation in off or all lights on regardless of ambient light when in hand.
 

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Discussion Starter · #18 ·
The 7 lights that stay on from dusk till dawn are connected to whatever device senses dark.

The 14 other lights are run through the NC contact of the time-delay, which is set to however many hours it is between dusk and 12AM. The coil of the time-delay is energized whenever the 7 lights are on.

Depending on what 'manual override' means, the hand contact will always energize the 7 lights + the other 14 on the load side of the time delay.

The auto position could be used to bypass the time delay resulting in all lights being on from dusk to dawn, or it could be connected in series with the dusk to dawn sensor resulting in normal operation in auto, no operation in off or all lights on regardless of ambient light when in hand.

That's my issue. When the hand contact is energized you are re energizing the time delay, thus timing out the other 14 lights. That's not good.

And your auto contact comment is just swapped with how I'd wire it. I put the time delay on the auto contacts and the normal operation of the lights on the hand contacts.




Correct me if I'm wrong or keep trying.
 

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Discussion Starter · #19 ·
The 7 lights that stay on from dusk till dawn are connected to whatever device senses dark.

The 14 other lights are run through the NC contact of the time-delay, which is set to however many hours it is between dusk and 12AM. The coil of the time-delay is energized whenever the 7 lights are on.

Depending on what 'manual override' means, the hand contact will always energize the 7 lights + the other 14 on the load side of the time delay.

The auto position could be used to bypass the time delay resulting in all lights being on from dusk to dawn, or it could be connected in series with the dusk to dawn sensor resulting in normal operation in auto, no operation in off or all lights on regardless of ambient light when in hand.
On the load side of the time delay? What side is load to you? And this did cross my train of thought. So when you throw it hand how are you not energizing anything else on the relay?
 

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That's my issue. When the hand contact is energized you are re energizing the time delay, thus timing out the other 14 lights. That's not good.

And your auto contact comment is just swapped with how I'd wire it. I put the time delay on the auto contacts and the normal operation of the lights on the hand contacts.

Correct me if I'm wrong or keep trying.
It's almost a trick question, walk away from it for 10 minutes.
then read this ~ !

http://forum.allaboutcircuits.com/showthread.php?t=15785

I might be wrong but I think your missing the point that a NC is on a timer, so is NO. So then you can get into the opposite thoughts of NO/NC and put the
hoa in the correct location!

Harry you need to be a teacher here and not a professor! IE get them to think not lecture them :whistling2:

:jester: > < What do i know...
 
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