GB213281A - Improvements in variometers - Google Patents

Abstract

213,281. Pelletier, G. March 22, 1923, [Convention date]. Addition to 207,825, [Class 37, Electricity, Measuring &c.]. Regulating transformers; condensers. - In a variometer as claimed in the parent Specification, two concentric windings are formed in sections and mounted on the stator so as to lie in different vertical and horizontal planes. Fig. 1 is a section and Fig. 3 a plan of one construction. Two rectangular or other insulating plates 2 are attached to a base-plate 1 and spaced apart by cross-pieces 3. Each of the plates 2 has two series of horizontal notches of unequal depth arranged alternately, for example, one series of notches 4 may be double the depth of the other series 5. Two separate stator windings 6, 7 are wound in these notches, the winding 6 completely filling the notches 5, but the winding 7 only filling the bottom part of the notches 4, so that the windings 6, 7 are completely separated vertically and horizontally. The windings 6, 7 are tapped and brought out to sockets on an insulating plate 10, the number of turns in circuit being variable by means, of plugs 11, 12. The rotor is in the form of a drum comprising two circular insulating plates 13 connected by an insulating sleeve 14 attached to a central shaft 15 passing through the stator. In the plates 13 are formed notches 16 in which are wound the sections 17 forming the movable winding. On the baseboard 1 are arranged sockets 24 for a thermionic valve and clips 21 for the reception of condensers contained in glass tubes 22 with terminal caps 23. The connections of the receiver are shown in Fig. 4. The winding 6 forms the primary inductance variable by fractions and is connected between the aerial 25 and earth 26 in series with a condenser 27, which may be changed at will for one of a different value. The other fixed winding 7 in series with the movable winding 17 forms the secondary winding and is connected in series with the condenser tube 28. The grid 29 of the valve is connected to one end of the winding 7 through a shunted condenser unit 30. The winding 6 may form the reaction coil, in which case the coupling between the coils 6, 7 is arranged so as to be the reverse of that between the coils 7, 17. The variometer may have a magnetic core, for example a tube filled with iron filings or fire iron wire may be inserted in the sleeve 14 of the rotor. The variometer mav serve as a .connecting transformer for a highfrequency amplifier, or for a resonance amplifier. A series of interchangeabe rotors for extending the range of wave-lengths may be provided for by forming the rotors with spindles serving simultaneously as supports and contact-pieces, and engaging sockets fixed on the base-plate 1. Two separate rotors instead of a single one may also be provided.