The mechanical tilter provides an easy and efficient way to dump metal coils, molds, dies and other heavy and bulky loads. Mechanical turners, sometimes referred to as coil positioners, are used to rotate steel, aluminum &, other non-ferrous coils, and other loads up to 90 degrees. They are employed in a variety of production and maintenance applications. The main advantage of crib type unwinders is the quick and effortless loading of the coils.
These machines are often combined with straighteners for faster loading and adjustment, lower energy consumption, and reduced maintenance requirements. Base smoothers also help save space in the plant. Magnetic levitation is a technology that has been developed to balance rotors without the use of test weights. Charpentier, J.
conducted a comparative analysis of synchronous motors without permanent magnet type bearings for fully magnetically levitated rotors. Lyu, Mindong; Liu, Tao; Wang, Zixi; Yan, Shaoze; Jia, Xiaohong; Wang, Yuming proposed a method of controlling rotor relieving for different orbital responses during landings on active magnetic bearings. The authors have also discovered that it is possible to achieve stabilized magnetic levitation by rotation without aligning the rotational axis of the rotor with the direction of the force of gravity. This is done by taking advantage of the symmetry properties of a magnetic levitation arrangement.
Qian, K X; Zeng, P; Ru, W M; Yuan, H Y; Feng, Z G; Li, L developed an apparatus and method for unloading a rotor bearing. The apparatus includes an electromagnet to levitate the rotor. In one example, a magnetic field sensor near the electromagnet is used to control the current that causes the rotor to levitate. In another embodiment, a method is provided that includes rotating the rotor, increasing the current to levitate the rotor and decreasing the space between the electromagnet and the rotor, and then reducing the current to cause the rotor to levitate with a minimum amount of electrical energy for the electromagnet. The authors have also developed a levitated impeller pump that uses only permanent magnets.
The rotor is supported by permanent radial magnetic forces. The impeller is fixed on one side of the rotor; the rotor magnets are mounted on the other side. In front of these rotor magnets, a driving magnet is attached to the motor shaft. Thereafter, the motor drives the rotor through a magnetic coupling. In laboratory tests with saline solution, in which the rotor is still or rotates at less than 4,000 rpm, the rotor magnets have an axial contact point with a spacer between the rotor magnets and the drive magnets.
The contact point is located in the center of the rotor. As the rotational speed gradually increases until it exceeds 4000 rpm, the rotor will axially disaffiliate from the stator and completely levitate. Since axial levitation is caused by hydraulic force and the rotor magnets have a rotating effect, the rotor rotates very stably during levitation. As a left ventricular assist device, this pump operates in a rotational speed range of 5000 to 8000 rpm, and its impeller is ensured to be levitated through its use. The permanent magnetic levitation drive pump retains all of the advantages of rotary pumps but overcomes all of their disadvantages associated with electromagnetic bearings. This makes it more suitable for applications than before. Lü, P; Hong, Z Y; Yin, J F; Yan, N; Zhai, W; Wang, H P studied on how to achieve stable balance in a rotating pump with passive magnetic bearings.
Qian K X; Wan F K; Ru W M; Zeng P; Yuan H Y found that it was possible to achieve stable permanent magnetic levitation centrifugal blood pumps. The position of this pump's rotor is measured by four Hall sensors which are distributed evenly and peripherally at its end against its magnetic ring bearing. The voltage differences between these sensors due to their different distances from this ring are converted into eccentric distance (ED).The results verify that if its rotational speed and flow rate are large enough then its maximum ED will be reduced to approximately half its space between its rotor and stator. Finally we observe how spherical rotors can be levitated by near-field acoustic radiation and analyze what factors affect their duration of free rotation time. It has been discovered that their rotational speed decreases exponentially with respect to time. The time constant of this exponential attenuating motion depends mainly on its levitation height, mass of its rotor and depth of its concave ultrasonic emitter. The high levitating height, large mass of its rotor and small depth of its concave emitter are beneficial in increasing this time constant and thus extending its duration of free rotation.
