On Sun, 11 Mar 2007 22:47:29 -0500, Terry
wrote:

On Sun, 11 Mar 2007 20:37:22 -0500, Mark Lloyd
wrote:

On Sun, 11 Mar 2007 16:42:34 -0500, Terry
wrote:

On 11 Mar 2007 12:38:56 -0700, "Terry" wrote:

On Mar 11, 2:22 pm, Mark Lloyd wrote:
On 11 Mar 2007 07:08:12 -0700, "trbo20" wrote:





Hi All

I am getting ready to update my largish family room and am considering
how to approach the lighting. I'd like to install flush mounted
fluorescents, halogen task lights, wall sconces and a switched outlet
in three separate lighting zones so that the room can be lit according
to its use.

In my switch box, I'd also like to have one master switch that turns
all three zones on or off regardless of the state of any of the other
zones. For example, if zones 1 and 2 are off and 3 is on, flipping
the master would turn on all 3. Flipping the master again would turn
off all three. Then flipping zone 3 once more would turn it back on.
It's a 3-part 3-way if you will.

Can this be done? I'm having a hard time wrapping my puny non-
electrician brain around it. If this is done, what's it called so I
can search for the wiring diagram?

That would be a 3PDT (3 pole double throw) switch. I don't know what
else to call it.

That switch is 3 electrically isolated but mechanically connected 3way
switches. Electrically you have 3 separate 3way circuits.


Kind of like a relay?

One way he could do it would be to use 3 latching relays and 4 on/off
momentary contact low voltage switches. (one for the master)





I seem to remember that relays work best with DC control voltage (AC
can be switched). I suppose you need a rectifier and diodes (to
isolate the buttons so they don't ALL become master).


The first sketch I did had AC in mind. Having DC would make things
simpler. With DC, you could use the same type master as you have for
the single switches. You could use diodes instead of a triple throw
switch.

I think most of the relays for the home are 24V AC/DC. How about this
one?

http://i15.tinypic.com/2rq1xk9.gif


Assuming you want to be able to control the lights individually, that
circuit will NOT work. The problem should be obvious, the coils for
one light are in parallel with the coils for the other one. The
correct function of the diodes is to keep them separate (which those
can't do).

The 4 individual (not master) buttons can be connected directly to the
coils, but you'll need a diode between each master button and each
coil (total 4 diodes). This prevents current from one of the
non-master buttons from operating the other light's relay. Your
circuit does not have this protection.

Diodes are needed for any button that controls more than 1 relay. The
number of diodes is equal to he number of relays controlled (here 2 +
2 = 4).

BTW, diodes don't cost much, and are easy to experiment with. I always
have a few 1N4001 diodes (50V 1A).
--
Mark Lloyd
http://notstupid.laughingsquid.com

"How could you ask me to believe in God when there's
absolutely no evidence that I can see?" -- Jodie Foster