> On 2020 May 14, at 14:21 , Skip Withrow <skip.with...@gmail.com > <mailto:skip.with...@gmail.com>> wrote: > […snip…] > > A question for TVB (or anyone else that might know), what happened to > the three Shortt clocks that he [Loomis] had?
About 100 Shortt-Synchronome systems were manufactured. There is not a central database of locations for the surviving instruments, as far as I know. I know the location of maybe a dozen or so — but there are plenty more than that in existence. Some are still in the hands of their original owners; some are in museums; others are in private collections. > Also of interest would be how > many still exist today, and how many in running condition Very few of the survivors of which I am aware are presently operating. The one at NIST’s library in Gaithersburg, for example, was maintained by a retired staff member. A few years ago he moved from the DC metro area. A vacuum leak developed in the master and the system stopped. The ClockWorks museum in London has had difficulty keeping their system operating. There are some tricks to its setup, the knowledge of which has not been well-maintained. > (and > Fedchenko Fedchenko engineered 4 pendulum-based systems: a clone of the Shortt-Synchronome, of which the highest known serial number is #27. These were manufactured by Etalon in Leningrad. At present three complete (master + slave) systems are known exist, and two slave-only units. I’m not sure that any of the three complete systems are operational; two may be capable of starting up but their ability to run for long periods of time is unknown. AChF #1 was a first generation prototype of the system for which Fedchenko is famous. It was placed in the first floor of a working building at KhGIMIP (Kharkov State Institute for Weights and Measures) and tested for 3 years (1955-1958) against the KKh-3 quartz clock. This model was not placed in production. Unless Etalon has it in archives, it may not have survived. AChF #2 was a second generation prototype built in 1956 — maybe lost or perhaps in Etalon archives. AChF #3: The highest known serial numbers, #36 and #37 (incomplete), came to light in the last six years. Thirteen survivors are known. Of these, four are in museums: one in Switzerland, one at the Greenwich Observatory, and two at the ClockWorks Museum (London). The remainder are in private hands. There is also an orphaned slave clock in private hands whose current location is unknown. The Greenwich one was installed by Etalon as a gift and ran for a number of years but has stopped for unknown reasons — possibly a vacuum leak. Unfortunately it’s built into a display cabinet that would have to be disassembled in order to service the clock. When I last visited, one of the two systems at Clockworks was operational but not kept in continuous service. The operational condition of the system in Switzerland is unknown. At least one system in private hands is kept operating, but not instrumented for measurements. > and Riefler)? Riefler made a vast number of models. I don’t know of an inventory of the partial-vacuum tank clocks. > There is something very satisfying about the tick-tock of a pendulum > clock, though I realize the Shortt's were not direct drive. The seconds-driving contacts of the Shortt-Synchronome make plenty of “tick tock”! Synchronome used a weight-assisted contact mechanism to ensure a reliable “make” and the weight gets reset by a solenoid each second. With care, one can do a lot to quiet down the noise to acceptable residential levels. But that’s another lengthier discussion. > > Regards, > Skip Withrow _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
