Patent GB-190405214-A (GB)
Title: Improvements in and relating to Controlling Electric Motors.
Inventor: GEIPEL WILLIAM
Filed: 1904-03-02
Granted: 1905-04-01
Abstract: 5214. Geipel, W., and Langeg, F. M. T. March 2. Dynamos and motors combined for transmitting power ; dynamos, regulating ; motors, controlling.-Relates to improvem e n t s in the shunt-wound motor-controlling apparatus described in Specification No. 5213, A.D. 1904, in which the main motor C, Fig. 1, is driven by an intermediate generator B, adapted to produce half the maximum voltage required by the motor C, the generator B and motor C being automatically connected in opposition across the constant - potential mains a, b when the voltage of the generator reaches its maximum value, which value is half that of the mains a, b, further increase in the speed of the motor C being produced by decreasing the voltage of the generator B, and finally by inserting resistance in the field s of the motor C. The motor A which drives the generator B is connected across the mains a, b through a starting-switch D, the armature d being connected with this switch through a rheostatic device E. The armatures of the generator B and motor C are connected, as shown, to the contact-plates of the change-over switch operated by the device K. When the generator B and motor C have been connected in opposition across the mains a, b, the brushes 10, 22, carried by the rod 0 which is actuated by the electromagnets L, spanning the contacts 8<5>, 9<5> of the rheostat E and the contacts 19, 21 of the change - over device K, the brush 7 introduces resistance 5*, 6* into the circuit of the armature d, thereby diminishing the speed of the motor A and consequently diminishing the voltage of the generator B, which is also partly brought about by the introduction of resistance 8*, 9* into the circuit of the field m ; the armature n is shortcircuited by the brush 14 spanning the contacts 17, 18 when the motor C is running at nearly full voltage, after which the motor A may be stopped altogether by opening the switch D. Instead of diminishing the speed of the motor A by means of the rheostat E, the switch D may be used, in which case the lever g may be slowly opened by engaging with the rod 0, or it may be operated by an electromagnet the circuit of which may be made and broken by contacts carried by the rod O. In order that the motor C may exert an extra torque on starting, the field winding s may be increased and resistance 11* ... 12* ... afterwards inserted in the circuit to reduce the field to its normal value. The rod O may be operated by hand, by solenoids, as shown, by a motor, or by a step-by-step mechanism, while its rate of movement may be regulated by clockwork mechanism 3, 4 adapted to drive fans 3*, 4*, the operating- mechanism 3<a>, 3<c> of the fan 3* consisting of a pawl and ratchet device set in motion by the rod O when moving to the left, while the mechanism 4<a>, 4<b> which operates the fan 4* is set in motion by the movement of the rod O in the opposite direction. In order to produce slow starting and quick stopping, the fan 3* may be so constructed as to offer a greater resistance to motion than the fan 4*. One set of mechanism only may be used, in which case the fan may be adapted to offer greater resistance when rotating in one direction than when rotating in the opposite direction, or the movement of the rod O may be regulated by a dash-pot or a centrifugal governor, or by a combination of such. In a modification, shown in Fig. 2, the generator B and motor C are connected in opposition, the speed of the motor C being increased from zero to half voltage speed by inserting resistance 8* ... 9* ... in the circuit of the field m of the generator B until the voltage of the generator B is practically nil, when the armature n is automatically whort-circuited by the switch J, further increase of speed of the motor C heing produced by inserting reistance 11* ... 12* ... in the field s.