| 摘要 |
962,754. Electric synchronous movements; electric motors; control of A.C. motors. PHILIPS ELECTRICAL INDUSTRIES Ltd. July 21, 1961 [July 26, 1960], No. 26560/61. Headings H2A, H2J and H2L. [Also in Division H3] The invention provides apparatus in which a double stator synchronous motor has the movement of its rotor controlled by means of a number cf bi-stable triggers actuated by a control generator. The poles of the two stators are relatively offset by 90 degrees so that if their polarity is varied cyclically, as in Figs. 1a-1d, the rotor 3 steps towards the right. By adjustment of circuit parameters great variation in speed can be obtained. The motor is reversible. In one embodiment, Fig. 2, operation of switch 8 triggers a monostable relaxation unit 52. This in turn triggers an astable relaxation unit comprising transistors 37, 38 which feeds pulses over line 31. Transistor 37, 38 and their associated gating circuits 23, 27 ; 24, 28; 25, 29; 26, 30; are cross-coupled so that the pulses on line 31 switch the various transistors in sequence to give currents in stator windings 4-7 such that the situations illustrated in Fig. 1 are obtained. Thus the rotor steps continuously until the astable unit is stopped, this being done after the return of unit 52 to its stable condition after a time dependent on the circuit parameters. In order that the rotor shall reach synchronous speed during the first pulse on line 31, this pulse is made longer than the others by capacitor 44 having a longer timeconstant than capacitor 43. The circuit of Fig. 2 includes lines 53, 54, the arrangement being such that the astable unit cannot be switched off until there is no negative potential on either of these lines. This occurs only when transistors 10, 11 are conductive, i.e. once every four pulses. Thus if monostable unit 52 resets during the fifth to eighth pulses then the astable unit will produce eight pulses and the rotor steps eight positions. This is stated to be of use in telegraph tape feed apparatus 13. Specification 962,755 is referred to. |
