| 摘要 |
1,274,360. Electric motors. MOSKOVSKY ORDENA LENINA ENERGETICHESKY INSTITUT. 24 Feb., 1970, No. 8782/70. Heading H2A. [Also in Division G1] The position of the rotor of a brushless D.C. motor is sensed by passing high frequency A.C. through the motor windings and sensing when the A.C. in the individual windings exceed a predetermined value, the A.C. in any given winding varying with the position of the rotor. The motor shown comprises three windings 1, 2, 3, energized sequentially from a D.C. source by thyristors 31, 32, 33. A.C. is passed-through the windings from secondary windings 7, 8, 9, of a transformer supplied from a h.f. source. A.C. only passes through a given winding when a magnetic amplifier, e.g. 37, in series with each secondary winding, is saturated by the D.C. flowing through the corresponding commutating thyristor. Low pass filters 22, 23, 24, in series with the windings 1, 2, 3, prevent A.C. from. flowing in the D.C. circuits. Capacitors 4, 5, 6, prevent D.C. from flowing in the A.C. circuits. Operation.-Assuming windings 1 to be energized with D.C., A.C. will flow through the winding from the transformer secondary winding 7. When the A.C. exceeds a pre-set value determined by a diode 40 and resistor 46, transistor 43 is turned on and triggers the thyristor 32 of the next stage. A commutating capacitor 34 turns off thyristor 31, magnetic amplifier 37 becomes unsaturated and stops the A.C. flowing in winding 1. At the same time an RC locking circuit 50, 53 increases the current through diode 41 and resistor 47 and so prevents transistor 44 from triggering the thyristor 33 of the next following stage. |
