AFA Panel 2

Blimey - seen tons of those.

The intresting bit, is the box to the right - the "AFA Relay" box.

Most installations I saw had either a Black, or Blue AFA drum bell box above the panel.

The bell-box contained (as standard) a Bell, tamper switch, 5 x R40 flag batteries, and 3 three relays.

The main switching relay- a large GPO one did all the tricks.

Then there was a small sealed relay, wired in a latch config, and then a much, much smaller relay.

This was held closed by, by a -Ve being fed through the N/O contacts in series through the panel- any relay (or tamper) opening would then trip the alarm (if it was set of course!)

The relay box pictured looks like a replacement to the Drum bell box.

Each circuit had it's own relay, that would each be held in by circuit batteries- Flag Cells at the end of each circuit. Again wired in a latching config.

The panel relays had 2 coils- one  for the circuit (as above) and another, that was series wired with each of the other circuit relays, when you set the alarm (providing your circuits were closed), you would hold the "Setting Push" button on the panel front, and turn the Key switch, this passed a current through the second coil of the circuit relay, operating them.

The meter on the front was connected to a "Circuit Test" rotary switch- it displayed the status of each circuit, and also the status of the circuit batteries.

From memory, the needle would sit in the centre (green scale) if they were OK, and circuit was closed.

The Red lamp, was an indicator for when setting that a circuit wasn't closed- to prevent the user from attempting to set the alarm, and activate it, and any auto dialler.

There was also a single circuit version too- which operated the same way; but didn't have the circuit relays in the panel.

I'll have to dig out the circuits I have for them and reminice!