Saltford Brass Mill Project
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Dynamo
In 1928, after the production of brass had ceased, the premises were bought by Eric Butler, a director of William Butler and Company, 'Tar, Rosin and Oil Distillers' of Crews Hole on the Avon between Saltford and Bristol.

Eric was a Freeman of the City of London, Liveryman of the Worshipful Company of Wheelwrights, and Special Commissioner for the Inland Revenue. He was also a keen sportsman who fished, piloted his own light aeroplane and played tennis and squash.

His reason for purchasing the mill was to use the building as a sports centre. He converted the area occupied by a set of battery hammers into a squash court, installed electric light to illuminate the squash court and adapted one of the waterwheels to drive a dynamo to provide power for the lighting; noting that at this time the national grid did not exist and Saltford itself was not provided with electric power.

He laid concrete floors and provided a concrete plinth above the flood level on which he mounted an 'Ediswan' (Edison-Swan) dynamo. The dynamo produced direct current (modern domestic supplies are alternating current) and was capable of generating 11 kW at 210 volts when rotating at 1450 rpm. Power was controlled from a switchboard, provided with a volt meter, ammeter, voltage regulator and distribution switches.

A combination of chain and belt drives were used to connect the waterwheel to the dynamo, enabling the dynamo to be turned at 1450 rpm with the waterwheel revolving at just over 9 rpm. With such a gear ratio fine control of speed, and hence voltage, would have been difficult. A small increase in the waterwheel speed, say to 10 rpm, would have resulted in the voltage increasing to 225 Volts which would have probably 'blown' the electric lamps.
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In 1956 the mill was sold to Mr & Mrs Sheppard, who operated as Bristol Boats Ltd. The Sheppards installed a bench saw adjacent to the dynamo, which rotated at 1600 rpm and was capable of cutting timbers up to 9ft long. The installation included three additional pulley wheels to connect the saw to the dynamo drive and a ‘belt shifter’ to enable the saw to be stopped without stopping the waterwheel.
Later Use
Dynamo