GB962102A - Improvements in and relating to electric control systems for winding, reeling or thelike apparatus - Google Patents

Abstract

962,102. Automatic voltage control for winding motors. ENGLISH ELECTRIC CO. LTD. Oct. 13, 1960 [July 13, 1959], No. 23951/59. Heading G3R [Also in Division H2] In an automatic control system, a dynamoelectric machine driving a reel onto, or from which, material is wound, is supplied from a variable voltage source controlled in dependence on the deviation of the armature current from a reference valve in a sense tending to correct the deviation, the field excitation of the machine being simultaneously varied, at a rate dependent on the magnitude of the deviation, in a direction tending to correct the deviation. As shown, an armature 10a of a motor 10, driving a reel 11 on which a web is being wound, is supplied from an armature 15a of a generator 15. A field winding 15f 2 of the generator is energized by a constant reference current, adjusted by a rheostat 19, a field winding 15 f 3 is connected to lines 20 which are energized during acceleration and deceleration to compensate for inertia, and a field winding 15 f 4 is energized from a magnetic amplifier 18. The magnetic amplifier has a control winding 18c energized in dependence on the armature current by the voltage across a resistor 16, and a control winding 18a energized in series with the reference field winding 15 f 2, so that the winding 15 f 4 is energized in dependence on the deviation of the armature current from a reference valve. A further control winding 18b is energized in series with the inertia field winding 15 f 3. The difference between the voltage across the resistor 16 and the voltage at a tapping 26a on a potentiometer 26 across the armature 15a energizes an armature 22a of a motor 22, having a permanent magnet field, driving a slider on a field regulator 14 for the field winding 10 f of the motor 10 and a slider on the rheostat 21. A generator 23 is driven by a rolling mill motor 24 to produce an adjustment of the voltage applied to the armature 10a in dependence upon the speed of the web 12. When the reel is stationary the armature current and hence web tension is determined by field windings 15 f 2, 15 f 4, the motor 22 being unresponsive. When the web is accelerating an increasing voltage is applied to the motor due to generator 23, the energization of the inertia compensating field windings 15 f 3 and the increased energization of field winding 15 f 4 through winding 18b, so as to maintain web tension constant during acceleration. Simultaneously, the motor 22 is driven at a rate dependent on the deviation of the armature current in a direction tending to correct the deviation by adjustment of regulator 14 and rheostat 21. At full speed the lines 20 are de-energized so that the amplifier 18 controls the field excitation of generator 15 to maintain the armature current, and web tension, at a valve determined by the setting of rheostat 19. In a modification, field windings 15 f 2, 15 f 3 are omitted and the amplifier 18 provides the total excitation. In a further embodiment, the generator 23 is replaced by a tacho-generator energizing a further field winding for the generator 15 and the motor 22 is energized in parallel with the field winding 15 f 4. The generator 15 may be replaced by a grid-controlled rectifier installation.