GB1013982A - Improvements in the manufacture of induction coils - Google Patents

Abstract

1, 013, 982. Inductance;power measurement; fault testing. H. C. HANSEN. May 1, 1962 [May 5,1961], No. 16388/61. Heading G1U. [Also in Division H1] One or more gaps in the magnetic circuit 10, 14 (Fig. 1) of an inductor 12 is filled with a deformable material 16, the inductor is placed in operating conditions similar to those in which it will operate when in use and is arranged to give an indication (on ammeter A, Fig. 2) of its inductance, the core structure being deformed to correct the inductance if the indication shows that its valve is outside the tolerance limit. The deformation is effected through shoes 42 or 26 which respectively reduce or increase the gaps when the pneumatic or hydraulic cylinders 50, 34 are actuated by manual operation of the valves 54, 38. The material 16 may be foamed synthetic resin. Two coils are provided TL 1 , TL 2 (Fig.2) which are of the same type as the coils 12 being manufactured to enable standardisation of the meter readings and to permit adjustment thereof by using new prototype coils if the type of coil being manufactured is changed. A wattmeter W enables a check to be made on the consumption in the coil so that unsatisfactory specimens can be rejected. Insulation testing can be effected when the gap has been adjusted satisfactorily by applying between the coil winding 12 and the core 14 a high voltage from transformer winding 67 the departure from normal of the voltage indicated by V being dependent on the production of a voltage drop in resistance 68 by leakage current. The circuits may be controlled by relays (R 1 , R 2 , R 3 , Fig. 5, not shown) under the control of push buttons so that an indicator lamp lights when the inductance is being checked and a warning lamp is lit when the insulation is under test. The coils are vacuum impregnated with varnish after the adjusting and testing. The apparatus may be adapted to adjust the coil inductance automatically and to reject automatically coils giving unsatisfactory wattmeter readings or unsatisfactory voltage readings from the h.t circuit.