Development of Electromagnetic Vibration Test est Apparatus for Ground Coils Applied to Maglev System. Administration Division

Size: px

Start display at page:

Download "Development of Electromagnetic Vibration Test est Apparatus for Ground Coils Applied to Maglev System. Administration Division"

Maryann Jenkins
5 years ago
Views:

1 PAPER Development of Electroic Vibration Test est Apparatus for Ground Coils Applied to Maglev System Minoru TANAKA, Ph.D Administration Division Masayuki ABA Masao SUZUK Senior Researcher, Senior Researcher, Laboratory Head, Electroic Guideway Technology Laboratory, Maglev Systems Technology Division s installed along the entire guideway length of a ically levitated (Maglev) transportation system need to withstand long-term outdoor use as they are vibrated by electroic forces when a vehicle passes. Verifying ground coil dynamic durability under conditions of substantial electroic vibration is important for ensuring the total reliability of the Maglev system. We therefore developed an electroic vibration test apparatus unavoidable for the bench test. Using this apparatus, we succeeded in evaluating the dynamic durability performance of ground coils in operation. Keywords: maglev, ground coil, electroic vibration, dynamic durability 1. ntroduction n the superconducting ically levitated (Maglev) transportation system, the ground coil is one of the most important components as it generates the propulsion, levitation and guidance forces acting on the vehicles. Two types of conventional ground coil are installed on the guideway of the Yamanashi Maglev Test Line 1). The levitation and guidance coils are installed over the propulsion coils. These ground coils, which are installed along the entire length of the Maglev guideway, need to withstand long-term outdoor use as they are vibrated by electroic forces when a vehicle passes. Verifying ground coil dynamic durability is important for ensuring the total safety and reliability of the system. We therefore developed an electroic vibration test apparatus for bench tests that can apply an electroic force on a coil conductor as a distributed load, to simulate the load conditions under actual train operations, and to evaluate the vibration characteristics and dynamic durability of the coil molding material under arbitrary running conditions.. Electroic vibration of propulsion coils Electroic force Fig. 1 Electroic forces acting on propulsion coil ( km/h) The major source of coil vibration is from the electroic forces generated between the ground coils and the onboard superconducting s (SCMs). Figure 1 shows the calculated electroic forces on a propulsion coil when four SCMs passed at a constant speed of km/h. and are force components, as indicated in the figure. A linear synchronous motor propels superconducting Maglev vehicles. When an SCM approaches a propulsion coil, attractive force acts on the coil. After the SCM passes by the propulsion coil, repulsive force acts on the coil. These attractive and repulsive forces vibrate the propulsion coil. t can be seen that the number of vibrations is equivalent to the number of SCMs passing by the ground coils. The number of vibrations equates to approximately 1.8 million over 3 years of commercial operations. Hence, it is essential to verify ground coil dynamic durability against electroic vibration for the safe and secure operation of the Maglev system. 3. Electroic vibration test apparatus for ground coils Figures and 3 show the configuration and a general exterior view of the test system, respectively. By installing a target ground coil so that it faced the SCMs, and by applying the current from the inverter power supply under arbitrary conditions, it was possible to simulate the actual vibration conditions that occur when a train passes a coil. The electroic forces resulting from the ic field of SCMs act directly on the ground coil conductor. The vibration amplitude is adjustable by varying the distance between the ground coil and the SCMs, the current amplitude of the inverter and the o-motive force of the SCMs. The vibration frequency is readily adaptable to vehicle running conditions by controlling the current frequency. The temperature Z Propulsion coil 11 QR of RTR, Vol. 8, No., May. 7

Shield plate Base + Superconduciting nverter Shield plate Superconducting Fig.

insulate it from the alternating ic field and thus restrain ic vibrations. The LabView software-controlled automatic control and measurement system we developed, shown in Fig.

2 Shield plate Base + Superconduciting nverter Shield plate Superconducting Fig. Electroic vibration test system configuration Cooling device Movable soundproof chamber of the ground coil is controllable by the performance of a cooling device and the interval times of the coil current. Since an SCM generates a larger alternating electroic force than those during actual operations when placed in an alternating ic field, the ground coil was covered with an aluminum shield plate to insulate it from the alternating ic field and thus restrain ic vibrations. The LabView software-controlled automatic control and measurement system we developed, shown in Fig., was adequate to enable unmanned long-term dynamic durability testing. Once we had established the test conditions prior to bench testing, the coil current from the inverter was automatically controlled for long durations. Experimental data were also automatically measured and monitored.. Electroic forces acting on propulsion coils Shield plate Superconducting (ground coil set inside shield plate) Fig. 3 General exterior view of electroic vibration test system Figure (a) shows the calculated electroic forces acting on the propulsion coil during actual vehicle running, when four SCMs passed by at a constant speed of km/h with degrees of phase lead. Since significantly affects the stress on the coil molding, the vehicle running conditions were rigorous for the propulsion coil. Figure (b) shows the calculated electroic forces from a bench test. t can be seen that the ampli- Superconducting Temperature Acceleration Strain Magnetic field Test conditions Coil current PC nverter Control Experimental data (vibration acceleration) Fig. Automatic control and measurement system QR of RTR, Vol. 8, No., May

Electroic force Electroic force 1 1 1 1.1..3.. (a) Running (calculation value) 1 1 1 1.1..3.. (b) Bench test (calculation value) Fig.

3 Electroic force Electroic force (a) Running (calculation value) (b) Bench test (calculation value) Fig. Electroic force acting on propulsion coil ( km/h, degrees of phase lead) 6. Electroic forces acting on PLG coils To reduce construction costs for the maglev system, we developed a PLG coil that combined propulsion (P), levitation (L) and guidance (G) force functions in one coil, as shown in Fig. 7 and quoted in reference ). Figure 8 (a) shows the PLG coil connections. The figure eight-shaped coil is composed of two asymmetric unit coils. The coils on both sides of the guideway are connected to each other by null-flux cables. A reverse current between the upper and lower coil units generates levitation forces, and a reverse current between the coils on both sides generates guidance forces. As the reverse current is induced by the displacement of the bogie from the central position on the guideway, it was difficult to simulate and Fz using these connections under bench test conditions. To solve this problem, we modified the connections from the arrangement shown in Fig. 8 (a) to those shown in Fig. 8 (b). Then two inverters controlled the upper and lower coil currents, respectively. To verify the equivalence tude and frequency of force component are equivalent to actual vehicle running conditions. Furthermore, repetitive vibrations during bench testing are advantageous for verifying dynamic durability.. Vibration acceleration of the propulsion coils Figure 6 shows the lateral acceleration of the propulsion coil during the bench test, during which an accelerometer was placed at the bottom of the test coil. The vibration frequencies ranged from to 1 Hz, equivalent to those of vehicle running speeds of approximately to 6 km/h. We verified that the vibration acceleration at a speed of km/h (approximately 1 Hz) was equivalent to that experienced during test-run operations. Despite certain peaks observed in Fig. 6, the amplitude caused the least of any specific problems. Fig. 7 View of PLG coil 6 Coil cable Coil cable Acceleration (m/s ) 6 Null-flux cable nverter nverter (a) Running (b) Bench test Fig. 8 PLG coil connections Table 1 Test est case parameters Case Coil current Displacement Y(mm) 1 Levitation Fig Frequency (Hz) Lateral acceleration of bottom of propulsion coil during bench test Propulsion, levitation and guidance - 3 Propulsion, levitation and guidance 11 QR of RTR, Vol. 8, No., May. 7

via load converters could be measured from the three directions referred to in reference 3). We simulated three different cases of actual operations under the bench test, as described in Table 1.

4 Electroic force 1 Fz -1 PLG coil - (measured) Fz (measured) -3 (calculated) - Fz (calculated) Case 1 Case 1 Case 3 Fig. 9 Electroic forces acting on PLG coil between the PLG coil connections tested under bench test conditions and during actual operations, the loads acting on the PLG coils installed in the test system via load converters could be measured from the three directions referred to in reference 3). We simulated three different cases of actual operations under the bench test, as described in Table 1. Figure 9 shows the measured and calculated electroic forces acting on the PLG coil. We verified that these forces matched those of the original design. 7. Propulsion coil dynamic durability test results We performed dynamic durability tests using an actual coil for propulsion, and a vibration test of cycles under an electroic force that generated approximately 1. times the ordinary stress on the coil s molding material. We only performed the vibration tests during the day, giving due consideration to the temperature rise characteristics of coils on a commercial line. The test period lasted for approximately 1 days. The test period corresponded to approximately 3 years of vibration on a commercial line, a fact determined by acceleration tests based on S-N curve characteristics obtained from separate fatigue tests performed on the molding material. During the tests, accelerometers were mounted on various parts of the coil surface to observe how vibration acceleration rates vary as time progresses. As shown in Fig. 1, the acceleration increased slightly at measuring point immediately after the vibration commenced, however, the increase is less in value. This confirmed that there is no specific problem concerning coil dynamic durability. During appearance inspection and insulating characteristic tests performed before and after the vibration tests, no change in properties was visible, and we verified dynamic durability equivalent to 3 years of commercial operations. The results indicate that our ground coil electroic vibration test apparatus is adequate as an effective means to evaluate dynamic durability. 8. mproving dynamic durability We evaluated various types of ground coils. Many test results indicated that the bush structures and materials at the bolt mount units, as well as the connections between coils and electrical cables, are essential parts for dynamic durability. Thus, we applied new fiber reinforced plastic (FRP) bushes as shown in Fig. 11 and new connections as shown in Fig. 1 to the PLG coils, as quoted in reference ). Using the test apparatus for electroic vibrations, we verified the significant improvement in dynamic durability performance. FRP bush Nut Bolt Mold resin (PLG coil) Fig FRP bush at bolt mount unit 3 3 are the positions of accerelometers. PLG coil Electrical cables Acceleration (m/s ) Number of repeated load cycles (1 6 ) Fig. 1 Propulsion coil dynamic durability test Fig. 1 Connections between coil and cables 9. Conclusions We developed the first electroic vibration test apparatus suitable for verifying the dynamic durability of ground coils on the assumption of actual electroic vibration. Using this apparatus, we succeeded in evaluating the durability performance of practical ground coils. QR of RTR, Vol. 8, No., May

5 Acknowledgment The authors would like to express their sincere appreciation to Mr. Yoshikawa and Dr. Murai (Central Japan Railway Company) for providing invaluable support. This work was completed in part with financial support from the Japanese Ministry of Land, nfrastructure, and Transport. References 1) Sawada, K., Tsuruga, H. and ida, T., Development of Ground Coils for Yamanashi Maglev Test Line, Quarterly Report of RTR, Vol. 37, No., pp , ) Aiba, M., Murai, T., Suzuki, M., Takahashi, N. and Yoshikawa, K., Development of the Ground Coil for Practical Use by the Combined Propulsion, Levitation and Guidance System, Proceeding of Maglev, pp.89-8,. 3) Fujimoto, T., Aiba, M., Suzuki, H., Umeki, T. and Nakamura, S., Characteristics of Electroic Force of Ground Coil for Levitation and Guidance at the Yamanashi Maglev Test Line, Quarterly Report of RTR, Vol. 1, No., pp ,. ) Suzuki, M., Suzuki, H., Aiba, M., Matsue, H. and Tanaka, M., Development of the Vibration-proof Fixing Part for Ground Coil, Proceeding of the 13th Jointed Railway Technology Symposium 6 (J-Rail 6), pp. 6-66, 6 (in Japanese). 11 QR of RTR, Vol. 8, No., May. 7

Development of Distributed-type Linear Generator with Damping Control. Toshiaki MURAI Chief Researcher,

PAPER Development of Distributed-type Linear Generator with Damping Control Takamitsu YAMAMOTO Researcher, Toshiaki MURAI Chief Researcher, Hitoshi HASEGAWA Researcher, Maglev Technology Div.,Maglev Development