| 摘要 |
<p>688,395. Magnetic amplifiers. BRITISH THOMSON-HOUSTON CO., Ltd. May 9, 1950 [May 20, 1949], No. 11522/50. Class 40 (iv). In a magnetic amplifier in which the current to load 10 supplied from A.C. source 7, 8 through windings 3 and 4 in series is controlled by the flux through a control winding 5, compensation for changes of voltage and/ or frequency of the A.C. source is effected by a winding 6, the terminals of which are short-circuited by a rectifier 19 to produce a flux in opposition to that of the control winding. The fluxes in the centre core due to windings 3, 4 are unbalanced by the flux from the control winding 5 so that alternating current (mainly harmonics) proportional to the load current is induced in winding 6. With the control flux from winding 5 constant changes of load current due to mains variations are compensated by changes in the flux from winding 6. A modification in which additional compensation is effected by supplying current to winding 6 from the A.C. source through a phase-shifting network is described with reference to Fig. 1 (not shown). Other modifications, not shown, include amplifiers having two separate cores and also a 4-limbed core. In the case of the latter the windings 5 and 6 are wound around both of the two inner cores.</p> |
