Electrically driven recording drums suitable for use by students for general experiments.Drive mechanism consists of Constant speed electric motor and accurate Gear-box contained in the base together with robust plate clutch.Engagement of various gear ratios are effected by sliding the lever into the slot marked with surface speed or by a knob in seperate models.6" diameter main cylinder and Stainless Steel spindle have been standardized- to make the same universal and interchangeable.Double electric contact arms are clamped on the main spindle-and a stout double-contact block is fitted on top of the base�Gear ratios-640 mm, 320 mm, 25 mm, 12.5 mm, 2.5 mm, 1.2 mm,0.25 mm, and 0.12 mm per sec, are effected by sliding lever into the slot marked with 8-surface speeds.
Optional : When longer records are needed a long paper extension device can be provided and fitted in position by a single set screw