GB756080A - An electrical recording instrument - Google Patents

Abstract

756,080. Recording-apparatus. TESLA NARODNI PODNIK. Feb. 4, 1954, No. 3318/54. Class 106 (4). Electric recording-apparatus, wherein a curve is recorded by perforating a moving chart 6 by means of spark discharges, comprises two parallel spaced conductive rods 4, 5 arranged transversely with respect to the direction of the chart's movement and both connected to one pole of a voltage source 9, with a measuring pointer 2 moving between the rods to form two series-connected spark gaps and the chart 6 moving in one of the gaps. The chart 6 passes over the rod 5, which is made rotatable to reduce friction. The rods 4, 5 exert equal and opposite electrostatic forces on the pointer 2 and so do not affect its reading. To adapt the apparatus for controlling the variable recorder the rod 4 is subdivided into two insulated parts both connected to the same terminal of the secondary winding of the transformer 9 supplying the spark voltage and respectively connected to two relays for actuating a regulating device in one sense or the other. The transformer is connected intermittently to the mains by means of a relay energized by a train of impulses while of the relays actuating the regulator, one closes its own holding circuit when energized while the other is connected to open this circuit and release the first relay, thus the variable is controlled to the value represented by the position of the insulated dividing point in the rod 4. The divided rod may be in the form of two wires 21, 22, Fig. 4, with their ends bent back and held together by an insulating ring 26, Fig. 5, the endless band thus formed passing round pulleys 23, 24 and enabling the set point to be adjusted. The rods 4, 5 may be arcuate.