Patent GB-430656-A (GB)
Title: Improvements in the production of automatic reciprocating motion from an alternating electric power source
IPC: H02K33/10
Filed: 1933-12-16
Abstract: 430,656. Reciprocating motors; induction motors ; electromagnetic switches; air supply to furnaces. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Summers, C. M. : 1204, Park Avenue, Fort Wayne, Indiana, U.S.A.) Dec. 16, 1933, No. 35467. Convention date, Dec. 23, 1932. [Class 35] [See also Groups XII and XXXVII] A reciprocating motor comprises an inductance 22 having an armature 21 movable against a mechanical bias to decrease its reluctance, connected in shunt with a condenser 23 and in series with an impedance 24 across A.C. mains. The arrangement is such that in the movement of the armature into and out of the airgap the changes in reluctance produce abrupt changes in the voltage across the inductance, so varying the electromagnetic pull on the armature and causing its reciprocation. In a. modification two such systems in parallel across the A.C. mains operate on a common movable armature so as to produce double-acting reciprocation thereof. In a further modification a pair of inductance and shunt condenser units act on a common armature to operate a reciprocating pump, and the inductances are centre tapped and connected so that part of each is in series with the other system and constitutes the series impedance therefor. In a further modification for operating the striker of a bell, the core of the inductance is fixed and an armature piece is mounted on the spring-biassed striker arm. A high impedance transformer is connected in series with the inductance and shunt capacity and a push button is provided for short-circuiting the secondary winding of the transformer to lower its impedance and produce reciprocation of the armature. The Specification as open to inspection under Sect. 91 includes a mathematical discussion of the properties of circuits comprising a self saturable inductance and capacity in parallel. An arrangement is described in which such an arrangement is included in series with the starting winding of a splitphase squirrel cage induction motor so that by variation of the voltage or frequency of the supply or the capacity of the condenser or the inductance of an auxiliary reactor in series with the starting winding, or due to the variations in impedance of the starting winding itself due to speed variations of the motor, the motor may be made to reverse, oscillate, or rotate through a predetermined number of revolutions in either or both directions. In a further arrangement the armature of the inductance operates a switch in response to variations of voltage across the circuit or variations of impedance in series therewith for switching or regulating purposes. The series impedance 24 may be short - circuited manually to cause operation of the switch or may be controlled by a thermally responsive switch or otherwise m accordance with the condition to be regulated. In a further arrangement, Fig. 18 (Cancelled), two inductance and condenser combinations 20, 25 and 20<1>, 25<1> operating on the same armature 21<1> are connected in series with resistances 24, 24<1> across the A.C. mains. Part of one or other of the resistances may be short - circuited by a thermal switch 37 so as to cause movement of the armature in response to temperature. Alternatively the resistances 24, 241 may be of metals such as titanium and zinc having equal and opposite temperature coefficients. The armature 21 may be arranged to control the draft mechanism in a furnace temperature regulating system. This subjectmatter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specifications 379,711 and 385,312.