I believe Mercury wetted contact relays also solve this problem.

I did post this further up the thread... "All of the contacts are made of 10% iridium and 90% platinum. The hipp toggle contacts pass between 400-500mA for the pendulum drive coil. Although

Howard, your clock would date to circa 1935 - but you probably kew that anyway! John

#2054 is very much standard, coils green, finish crackle, buffer yes, case oak flat top, pilot no 1. type small movement. I've no idea what Roller wire/plate refers to! Clockdoc website interesting

You are right, connected to power supply unit which masked the problem but again it stopped overnight. Investigating further found gap across contacts had increased. Having set the gaps at normal room

I have run mine for many years on 3 volts - two Duracell D cells. Ihave consistently found that a pair lasts about a year, give or take. (I'm driving a single dial - just the clock's own one). If the

Hi Howard, That should be a standard 1930s synchronome. If it has a pilot dial then it is normally run on 6 V (nominally 4.5v master + 1.5 per slave, though of course as you say it is designed for

I can’t comment on power consumption as I run several clocks from a float charged battery (multiple C sized NiMH cells - now about 15 years old) - but 280 mA is on the low side for a Synchronome.

My Synchronome #2054 ran for 45 days before latch failed to reset. Setup is transmitter and pilot at 11.5 ohms running at nominal 3 volts and 280mA from 2 Energizer Max D batteries. Thought it might

On a visit to Sydney Australia in 2007, I was privileged to visit the building that houses Father O’Leary’s Clock (thought by some people to be a preaccessor to the Shortt Synchronome system). I

The contacts in the PO 36 were designed to 'wipe'. That is, that they continued to travel after contacting which led one to wipe over the other thus removing any oxide build up. I am not sure of the

A wee bit off-topic, but....... It should perhaps be remembered that, as Malcom has said, a reverse current is induced in the coil by the collapsing magnetic field when the circuit is broken. When

When the switch breaks, current is still flowing in the magnet coil, as the magnetic field collapses in the iron core, reverse current is induced. Since the circuit is broken the voltage rises very

Interesting. The Silent Electric (closely related to early GPO clocks) uses make before break and resistors (unknown, but very probably just like the GPO ones). The were designed to work with Silent

Another thing about contacts: Some level of current must be carried through mechanical contacts to prevent buildup of oxide or other contaminants which will eventually inhibit

The GPO used a 200 ohm resistor in series with a 1 micro farad capacitor across the contacts on later type 36 clocks with simple make contacts. The earlier types with make before break contacts had a

They didn't have Silicon diodes in Strowger days, only Selenium, which devices were leaky and bulky. R/C was the appropriate tech. Now, Si.

Hi Darren, You are quite correct, but there are also other ways to minimise the voltage across the contacts as they open. One is to put a capacitor in series with the power supply such that it is the

Ernie, In order to photograph the commutator switch, I will have to stop the clock and lift out the movement. The commutator is mounted on the back board, but the spindle which drives it is part of

Thanks Ian for the offer of pictures. Thanks Thomas for the suggestion of the h-bridge circuit. Since I have modefied the T&N to deliver a contact closure for 10 seconds every minute, I couldn't