Patent GB-190605013-A (GB)
Title: Improvements in or relating to Electricity Meters.
Inventor: BLATHY OTTO TITUS
Filed: 1906-03-01
Granted: 1906-10-04
Abstract: 5013. Blßthy, O. T. March 1. Energy meters of the induction type. The changes of current or pressure and the corresponding changes in the field strength of the main or shunt electro-magnets are arranged to be more or less than proportional to each other, or even in certain cases inversely proportional, according to requirements. A movable magnetic part is included in the magnetic circuit, or in a magnetic shunt of the field to be influenced, or in the magnetic circuit of an inductance coil connected in series with the electro-magnet, the position of the movable part changing in accordance with variations in the current, pressure, or frequency. In the arrangement shown in Fig. 1, the field produced by the main current coil H increases in greater proportion than the current, in order to balance the increase in the braking effect of the main current field itself, the movable part A being drawn inwards against the action of a spring F or other controlling-device, such as a weight or some separate magnetic force. The movable part may be rotatably mounted, and the required relationship obtained by suitably proportioning the air-gap and the closing part. In the arrangement shown in Fig. 4, the magnetic flux produced by the shunt coil N is divided into an inoperative portion and an operative portion, the movable part being arranged in the path of the latter, which thereby changes in greater proportion than the pressure in order to compensate the effect of changes of pressure or frequency, as explained in Specification No. 1487, A.D. 1906. A similar division may be effected by connecting an inductance coil in series with an electro-magnet of the kind shown in Fig. 1. In the arrangement shown in Fig. 6, the magnetic flux produced by the pressure coil is divided into operative and inoperative portions as before, but, in order to dispense with a separate brake magnet, the operative field is arranged to vary inversely as the pressure; the movable closing part A is arranged in a magnetic shunt and is rotatably mounted and controlled by a spring F or other force. The same effect may be obtained by connecting an inductance with a movable spring- controlled armature in series with the shunt electro - magnet, which in addition may be itself arranged as in Fig. 6, the two movable parts cooperating to effect the desired relationship. By making the strength of the main field depend not only on the current but also on the square of the pressure, the brake magnet may be reduced in size, replaced by an electro-magnet, or entirely dispensed with. This result is obtained by controlling the position of the movable closing part in the core of the main current coil either by means of an auxiliary pressure coil or electro-magnet, or by connecting it to the movable armature of the above - mentioned variable inductance device. Or the movable part may be controlled by the shunt coil itself as shown in Fig. 9 ; a movable part A in the core of the shunt electro-magnet N is connected by a link R to a movable part D of the core of the main current electro-magnet. This arrangement may also include the correction of the main current magnet described with reference to Fig. 1. To adjust the phase relations of the various fields, the movable part or parts may be provided with short-circuited windings or copper strips T, Fig. 6.