Synchronome slave dial for alternate polarity system

Dial is 8.5 inches across. Circular metal case with domed glass to dial aperture.

Movement with rotating armature. Needs alternate polarity pulses at 30 second intervals. Click for movement

Although the item has no markings, it has been identified for me by a knowledgable friend who has equipment containing this type of dial and which is known to be of Synchronome manufacture.

Systems using pulses of alternate polarity were very common in Europe but are not commonly found in the UK.