Patent GB-592209-A (GB)
Title: Improvements in and relating to dynamo electric machines
IPC: H02K47/16
Filed: 1940-01-23
Abstract: 592,209. Electric control systems. TUSTIN, A., PARTINGTON, W., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Jan. 23, 1940, No. 1408. [Class 40 (i)] [Also in Group XXXV] An electric load device is coupled to a controlling apparatus through a metadyne having its secondary brushes in circuit with the load device and its primary brushes connected through a closed circuit, the controlling apparatus, which is supplied from a circuit independent of the said closed circuit, being arranged to apply or produce between the secondary brushes a voltage which varies with the voltage or current output of the controlling apparatus. The voltage between the secondary brushes may be produced by a stator variator winding on the metadyne which is connected with the controlling apparatus. By these means the metadyne output responds quickly to current or volt variations in the control circuit, e.g. when used for controlling motor excitation or follow-up position controls, and the phase lags in the control circuit or introduced by the various elements of the system are compensated or converted into a lead, of amount depending on the frequency, in the final output current. In Fig. 1, the control circuit (not shown) is connected to a. stator variator winding 5 producing a field in the commutating axis of the primary brushes a, c which are closed through an inductance 4. The load 3, the current in which is to respond to that in the control circuit is connected'to the secondary brushes b, d. It is shown in the Specification that the load current at 3 is increased in relation to the controlling current and that above a certain frequency in the control circuit, and over a substantial frequency range, a phase lead with respect to the control current is produced in the load current and that power amplification may simultaneously, be obtained. Response to low frequencies or current changes in the control circuit may be increased by a series winding 6, Fig. 4, between the primary brushes giving a flux in the secondary brush axis either with an inductance 7 between them and a shunting resistance 8 across them or, in addition, with additional series and shunting resistances 9, 10, as shown. In addition (Figs. 5 and 6, not shown), or alternatively, a winding in series with the load circuit 3 may be arranged to give a flux in the axis of the secondary brushes b, d. Variator windings in the output circuit of the control apparatus may be used to produce E.M.F's. at both primary and secondary brushes and it is shown that the load current of such a machine will be in .phase with the, control current even at high frequencies. In another arrangement (Fig. 8), the metadyne 1 controlled directly by the control circuit acts as an exciter which feeds, from its secondary brushes, the variator coil 13 of a second metadyne 14, the secondary brushes of which supply the load circuits 3. Fig. 9 shows a form in which the primary axis field is produced without a stator variator coil, the secondary brushes b, d being connected through the inductive load 3 directly from the control apparatus through the loads' 15, 16. The primary brushes are connected through a choke 17 without or with a series coil 6, inductance 7 and shunting resistance 8, as shown. This arrangement gives phase advancement without power amplification, but by causing such a machine to feed a variator winding on the secondary brush axis of a second metadyne, the secondary brushes of which feed the load, power amplification may be obtained. When the secondary brushes supply the armature of a motor 20, Fig. 12, or its field 25, 26, the primary brushes also may be connected to other field coils 21, 22. If the brushes b, d be connected to the motor armature, the field coils 27, 28 are energized from a constantvoltage source, and the motor torque will depend on the current at the brushes b, d. In another arrangement, Fig. 13, a metadyne 1 feeds one field coil 3 of a controlled machine, not shown, on which a second field coil 3a is fed from the secondary brushes b, d of a second metadyne 30 having on its secondary brush axis a variator coil 31 in series with the variator coil 5 on the primary axis a, c of the first metadyne. Thus, the two machines produce separate components in the energization of the load device. The arrangements described besides being used for control of armature of excitation circuits may be used in follow-up systems for governing the movement of objects by motive means other than electrical, for example for controlling a moving coil device governing a hydraulic variable velocity ratio transmission arrangement as described in Specification 592,208.