Fabrication and test of an electric spindle integrated with an electromagnetic balancer
This paper focuses on the development of an electric spindle integrated with an electromagnetic ring balancer. Firstly the electromagnetic ring balancer is designed and then 3D model of self-balancing spindle integrated with this balance er is created. Based on the design, an on-line balancing principle of self-balancing spindle is proposed. The prototype machine fabrication process of the balancer's key parts including coil, counterweight disc and toothed disc are discussed. For an actual spindle, the detailed design and development of this balancer are done, particularly the balancing craft of the combined rotor is done on a balance machine before delivery. By installing the balancer on the front end of spindle using flange, a self-balancing spindle prototype is obtained. In workshop, the vibration test of the developed self-balancing spindle is carried out in the range of 3000r/min to 9000r/min. The result shows the developed self-balancing spindle has a vibration velocity below 0.5mm/s. Finally the two eddy current sensors are applied to evaluate the vibration suppression capability of balancer, the experimental result is that about 15um peak-peak value can be eliminated when the correction value of balancer changes from 0 to 38.55g.cm in 3000r/min.
Actuating Principle of Online Automatic Balancer with Counter Weight Driven by Magnetic Force
Kinematic precept of mass block in automatic balancer is proposed following the principle of online automatic dynamic balancing.By combination of electromagnet and permanent magnet,the magnetic circuit of the balancer with ring coil and rare earth permanent magnet is designed.Actuating process of the balancer is discussed and then a step drive voltage waveform is defined.For the high-speed grinding motorized spindle 170MD12Y16,the mechanical structure and dimensions of the balancer are schemed out.The electromagnetic simulations for the designed balancer are conducted and the better coil ampere-turns and reluctance adjusting ring thickness are then determined.The validity of simulation results is verified by a balancer driving experiment and the desired voltage value and its duration time are also determined.the designed balancer has a stable operation process without out-of-step and fluctuation around balanced position when the ampere-turns are considered as 1 kA,the reluctance adjusting ring thickness 0.2 mm,the driving voltage 12.4 V and the voltage duration time 120 ms.
Comparison of a Radiometric Procedure with Conventional Methods for Identification of Neisseria
A radiometric procedure was compared with the conventional cystine tryptic agar (CTA) sugar fermentation method for identification of Neisseria species. Four different ATCC cultures of Neisseria were identified by both procedures with identical results. The only difference noted was that the radiometric procedure required 3 h for completion, whereas the conventional CTA sugar method required overnight incubation. The radiometric procedure was also compared with the fluorescent antibody (FA) and CTA methods for identification of Neisseria gonorrhoeae. The organisms examined were gram-negative, oxidase-positive diplococci isolated from 49 clinical specimens sent to the laboratory for bacteriological analysis. Results obtained by both CTA and FA procedures were comparable. However, the radioisotope method appeared to be superior to the other two methods in that only one isolate identified as positive by both the CTA and FA methods was not identified radiometrically, whereas four isolates positive by the radiometric method were not identified by the other two procedures. Thus, a total of seven more positive identifications were made radiometrically than by either of the two other methods. All positive identifications were confirmed by a reference laboratory. These results indicate that the radiometric procedure is more rapid and reliable as compared with both the CTA and direct FA methods and, thus, may serve as a valuable addition to the methodology available for diagnostic microbiology.