| 摘要 |
1,103,448. Control systems for consumption apparatus. DANFOSS A.S. 24 Feb., 1965 [24 Feb., 1964], No. 7997/65. Heading H2H. [Also in Division H3] In a multiphase switching circuit, having a junctionless non-rectifying solid state switch 9, 10, 11 capable of switching from a high to a low resistance condition when a threshold value of an applied voltage is exceeded and reverting to the high resistance condition when the current through the device falls below a holding value connected in each line of the supply a control device 12 is connected to apply timed control voltage pulses to the individual solid state switches at a rate of one per 180 electrical degrees in each phase to produce the desired switching. The switches can be polycrystalline solid state switches consisting predominantly of tellurium with the addition of elements from Groups IV and V of the Periodic Table. Solid state switches 15, 16, 17 isolate the control device 12 and delaying devices 13, 14 from the supply and the control voltage device 12 is coupled, as indicated at 18, to the supply so that the pulses are applied in the required phase sequence. Output regulation can be obtained by including a phase shifter in the control device. In a modification (Fig. 3, not shown), the switches are formed as a single unit having a common star point electrode (22) on which is mounted the solid state switch material and the three electrodes (24, 25, 26). In a further circuit (Fig. 5, not shown), each supply line has two series connected solid state switches and when the control voltage is applied across one of these switches to make it conduct the other is caused to conduct by the application of the supply voltage across it. The other phases are similarly switched on by the delayed pulse obtained from the delay devices 13 and 14 which include isolating transformers. In this arrangement the switches can be switched on together by D.C. applied (at 31) to the control device 12 via a transformer (28, 29) and line (27). |
