Sensitivity Meter also reflect the important parameters meter turntable shaft rotational friction torque; the higher the sensitivity, indicating that the friction torque smaller, less mechanical wear, longer life meter. Thereby increasing the sensitivity of the meter, watt-hour meter is an effective way to improve work performance. Sensitivity Meter, usually starting current meter with a measuring wheel begins to turn when quantitatively expressed meter currently in use, the starting current is generally not more than 5%.
For example, SA's energy meter starting current must be 25mA or less. Namely to reduce the starting current meter mechanical meter increase sensitivity is to reduce the friction torque meter turntable rotation. Common meter turntable are to be supported by the axial magnetic bearings, the radial mechanical vehicles still supported by a bearing, such a structure is difficult to further reduce the friction torque. On the trial of radial magnetic bearings to support the meter dial so that the starting current is reduced 5 times, that sensitivity meter increased by 5 times. This paper describes the structure and principles of radial magnetic bearings meter.
The most commonly used magnetic energy meter, almost all of this axial magnetic radial mechanical support structure. In these constructions, mechanical support mostly with a radial bore and a needle bearing turntable shaft composition, the finer the needle theory, the shorter arm of the friction force, the friction torque is smaller, the more sensitive meter high, life is also longer.
Thus, in the structure of the existing axial magnetic energy table, a significant reduction in the starting current and increase sensitivity meter is unrealistic, even impossible. Rotary shaft 2 7 magnet 4 and 9 are fastened together, the lower end of the shaft by a bolt 5 wore.
Since the magnet mutual repulsion magnet 9 and 10, two magnets arranged concentrically Temple Street sauce; and because the magnet 10 is fixed to the upper end meter frame, its magnet 9 namely turntable shaft 7 has a push-up force FI; same magnets and magnet 3 also has a mutual exclusion between 4 force, two sons magnetic policy Qian Gang Temple also concentrically arranged, but the magnet 3 is fixed to the lower end meter frame, its magnet 4 namely turntable shaft has a downward thrust FZ. Suppose turntable and other rotating parts by weight of G, then dial the axial force F between the lower end of the bolt 5 should be: F = G a Fl + FZF, FZ by adjusting screw 7, so that the two different sizes of the upper and lower magnets changing the distance between the changes, so the size of F is adjustable, it can theoretically tends to zero (but not equal to zero, otherwise reach the stable magnetic balance).
Radial magnetic energy table, turntable rotating turntable friction only at the contact point shaft 7 and the bolt 5. As described above, the force of the contact point can be adjusted to a small, upper turntable axis and can be made into very thin unlimited (unlimited arm reduction), together with other measures to increase the contact surface finish, etc., in the zero friction point of contact is possible. That is, the radial magnetic energy meter can develop into zero friction meter.
Principles and structure of the production of LD Holley had a type 1 meter Qiu trial, the starting current is reduced to 1%. Practical research problems to be solved is the problem of rigid radial magnetic bearings, that big, there must be between the small magnetic repulsion is large enough to ensure the meter wow can not change the tilt.
