ECN Forum Forums General Topics of the Trade General Discussion Area Lighting a tunnel?

Thursday...

OK I and others feel that we cant just show you.... You're a student, and this is a learning process.... I and others have schematics we could just send you, but aren't... And we too have some different ways of doing it, there are several.

However, I am gonna give you a hand in the way you approach the problem. (This is how I approached the problem.)In this trade, troubleshooting, and by proxy, design of electrical circuits requires an understanding of the required operation... So lets detail what the circuit needs to do:

• Either needs, or is limited to 6 lights, and 6 switches.(For now, just draw on a piece of paper what is known. i.e. 6 circles in a row representing the lights.)
• Only two lights can be on at one time.(Assuming you're entering a tunnel, the first light is on. Mark it with a pencil.)
• The switch used, changes the state of the light behind you, and the light in front of you.(By this, one can assume that the maximum of two lights that can be on, are going to be grouped together, pencil the next light on.)
• The light over your head does not change state while operating the switch at that location.(The switch doesn't operate the light over you're head.)
• Limited to the use of toggle type switches. (3-way, 4-way, Double-pole, or single pole. So for visual referance draw an example of each type of switch at the bottom of the page.)

For simplicity, assume if it is a DC circuit, every light has a negitive. Or if AC every light has a neutral. Just focus on what the light needs to operate, a positive, or hot to operate. And removal of that positive, or hot to shut it off.

Now "Walk the circuit"

You enter the tunnel, and approch the first light, and switch. The light you are at, and the light in front of you are on.

At the next light, you need to turn the one off behind you, and the one in front of you on.

Look at the examples of available switches, and try each one in the situation. Be creative, because they don't have to be used in the traditional way.

Now, you are on your own....

Definitely a point to emphasize. You need to apply some lateral thinking with problems such as this and not be trapped by what you might regard as the "normal" way to use a certain type of switch.

I think that it can be done code legal with one single pole, one double pole and 4 3-ways.
Don

well i would like to thank all of you for you help on this matter, it is greatly appreciated

strokezilla,
Did any of the students solve this and get extra credit?
Don

not to my knowlage, i ran out off time after my last hands on final, i only had enough time to get all my boxes up and run all my wires didnt have enough time to wire all the fixtures and switches wish i had about a hour more and i think i could have gave it a run

Here's a little diagram:


Simple yet effective.

{Message edited to fix up link.}

[This message has been edited by Trumpy (edited 10-01-2005).]

Hmmm..... That gives you one light at a time.


The way I understood the problem is that you have six lights, each with a switch on the wall below and that at any one point in time you have two lights illuminated.

So if, say, lights #2 and #3 are on when you throw the switch at #3 you turn off light #2 and simultaneously turn on light #4. Then when you reach #4 throwing that switch will turn off #3 and turn on #5, but #4 will stay on.

It's easy to do with just simple 3-ways at each point if you use the "illegal" method.




[This message has been edited by pauluk (edited 10-01-2005).]

Paul,
It can be done in a code compliant manner.
Don

I got in a legal method, but screwed up....

I have "On - through - Off - On - Back through - Off"
http://www.markhellerelectric.com/tunnelsw.pdf

I messed up on "through twice", and there is a way to do it like this by moving the combinations around. But it hurts your brain after a while....

I get enough of that at work!

This is a complicated set of switching for what it is... But there is a way to do it to cover the combo of "On - through - Off - On - Back through - Off" And, "Through Twice"