GB419055A - Device for generating or controlling the magnetism of an alternating current magnet acting on an armature - Google Patents

Abstract

419,055. Electromagnets; motors ; transformers. HOFFMANN, (nÚe v. PLOCKI), E., 13, Grundstrasse, Oberl÷ssnitz, Dresden, Germany. Feb. 4, 1933, No. 3500. Void [Abridged as open to inspection under Sect. 91 of the Acts, Aug. 5, 1933]. [Classes 35 and 38 (ii).] Motors with unwound iron armatures.-An electromagnet a, Fig. 2, is provided with a primary winding 1 connected to an alternating current supply and a secondary winding 2 which when loaded, e.g. by short circuiting at the contact c, causes a sufficient increase in the stray flux between the windings to attract an armature b ; in the form shown in Fig. 7, the armature b completes the magnetic circuit of the magnet a and is released when the coil 2 is short circuited. A further modification includes a pivoted armature with a limb in each of the armature positions shown in Figs. 2 and 7. The magnet may impart a continuous vibration to the armature which may constitute or carry a sound emitting diaphragm, or the hammer of an electric bell. A vibrating contact may be included in the circuit of the secondary coil. It is stated that the coils may be placed on a common arm or on divided arms and they may be disposed one above the other. A stationary iron member may be placed between the coils. The apparatus may be used as a transformer supplying a low voltage, for example 20 volts, and a tertiary coil may be disposed in such a position to prevent actuation of the armature during such use of the magnet. The tertiary coil may be connected to the primary or secondary coil. Pole shoes may be provided, for example by stamping the laminµ, and such shoes may carry an auxiliary winding supplied by the secondary coil. In order that the magnet may be used in connection with toys, the apparatus is formed with suitable holes. The term armature is stated to include rays, electrons and discharges. Fig. 5 shows the invention applied to a motor, the circuit of the secondary coil being periodically interrupted at c due to the rotation of the pole wheel b. The rotor b may have a winding supplied from the secondary coil 2, and this winding may be tapped.