Gallery of Synchronous Movements

Abstract

The purpose of this gallery is to illustrate synchronous movements, mostly from the British domestic synchronous clocks illustrated in the Chaps. 7, 8, 9, and 10, and to provide information on individual movements. All the movements were intended for use on the UK 50 Hz AC mains supply, and are mostly illustrated as found. Movement covers are usually moulded from Bakelite or plastic. The generic information in Chap. 3 on how synchronous movements work is suitable for most of the movements illustrated. The exception is the Marigold movement and explanations are included in its description. Most manufacturers made only a small number of different synchronous movements, with some variations to suit different clocks. The exception is Smith who made at least 13 different movements, together with a range of variations to suit different clocks. Both reluctance motors and magnetised motors can be satisfactory in service. The rotation speed of motors was a compromise. The most popular was 200 rpm, but this was not universal. Synchronous motors are not inherently self starting. Many clocks had manual start motors. Some had self starting motors, but reliability of self starting methods was sometimes a problem. Two types of reduction gear were used. In one type the reduction gear is similarly to the going train of a conventional mechanical clock. In the other type one, two or three worm gears were used. Both types can be satisfactory in service.