Nate Nagel wrote:

I have never heard of this but it sounds cool. I am guessing that the
switches are momentary SPDT and the relays latch either way? That would
be incredibly easy to add additional controls to, no need for annoying
three way switches etc... if it works as I imagine, why wouldn't it have
caught on? Too much cost? wouldn't meet current code? just curious

nate

Correct. Momentary switches. The 24V is rectified, so
a DC pulse is applied to one winding or the other of the relay.
The relay then latches magnetically and needs no more input power.
A switch anywhere else in the house can then cause the relay to
change state.

A nice application is a large property where outside lights
can be switched on/off from dozens of indoor locations.
Or, a bank of switches can control *any* light in the house from
one location!

The system *did* catch on and was quite popular.
But this was 40 years ago!!

I suppose X10 has supplanted it, but the system is
still being promoted in commercial applications where a
minicomputer controls the relays. Endless possibilities!

Jim






RBM wrote:

These relays are cylindrical and fit into a 1900 box with the bulk of
the cylinder sticking out of the box(the low voltage side). They are a
pain in the ass in that you can't just replace switches with dimmers,
but the damn things seem to last forever. The "buzz" sound only occurs
while a switch is being pressed, then the relay latches into the open
or closed position



"Speedy Jim" wrote in message
.. .

RicodJour wrote:


wrote:


As Speedy Jim said these are 12 volt AC switches that operate the
relay contacts for the normal 120 volts AC. There is nothing wrong
with this type of system. It is safer and more flexible. A certain
amount of hum is normal because the solenoid coil that operates the
relay contacts gets magnetized by a 12 volt 60 cycle source coming
off of a transformer. If the solenoid buzzes to much then it's time to
replace the relay.



This is a new system on me and I have a couple of questions for you.

What's the typical size wire running from the low voltage switches to
the AC contacts?
Could you demagnetize the relay or would that mess up the coil somehow?

R



The system has a 24V transformer (and a diode rectifier).
#18 gage low voltage wire (think bell wire) connects the switches
to the relays and to the 24V power supply.

The "Load" side of the relay (relay contacts) has 120V
with either #14 or #12 "house" wire connecting the relay
to the lights or whatever it is controlling.

"Could you demagnetize the relay"
Does not compute...

Jim