Design and Voltage Supply of High-Speed Induction - Aaltodoc

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52 5 COMPARISON OF ROTORS FOR 60 KW 60000 1 /MIN HIGH-SPEED MOTOR In this chapter, a copper coated solid steel rotor and two solid steel squirrel cage rotors are compared. The rotors were introduced in Sections 3.2 and 3.5. The solid steel squirrel cage rotors were designed to combine the mechanical properties of a solid steel rotor and the electromagnetic properties of a squirrel cage rotor. The comparison was made for a 60 kW 60000 1 /min motor. The tests were done having two identical motors coupled ‘back-to-back’ with a flexible coupler. The back-to-back test setup and the rotors tested are shown in Fig. 5.1. During the measurements, there was a specific opportunity to measure the rotor surface temperature on-line. The temperature was measured with an infrared camera via the cooling duct dividing the stator stack. Only the exhaust pipe of the cooling air had to be removed. This is done to the motor on the right in Fig. 5.1. The figure also shows a stripe of paint at the surface of the rotors, painted for the temperature measurement purposes. Power 60 kW Voltage 400 V Supply VSI Speed 60000 1 /min Stator winding 3 phase, full pitch Stator connection YY Stator slots 36 Parallel paths 2 Poles 2 Insulation class F Cooling Forced air cooling Bearings AMB Load Back-to-back Fig. 5.1 A photograph and data of the 60 kW 60000 1 /min high-speed motors coupled with a flexible coupler. From left to right, 16 bar, coated and 26 bar rotors.
The copper coated solid steel rotor is similar to the rotor used for the 65 kW compressor drive presented in the previous chapter. The circumferential speed at 60000 1 /min is 280 m /s. As mentioned in Section 3.5, a maximum speed of 50000 1 /min was specified for the squirrel cage rotors. Thus, the comparison was made at 50100 1 /min, the circumferential speed being 235 m /s. Even at this speed, the use of a laminated squirrel cage rotor is not possible. Reasons for this were discussed in Chapter 3. 5.1 Measurement setup In the comparison, two similar high-speed motors were used. The motors were coupled and the other motor worked as a motor tested and the other as a load machine, i.e., a generator. Both machines were connected to a VACON CX 90 (90 kW, 210 A) VSI supply. The DC-links of the frequency converters were connected together. With this kind of a set-up, only the power loss was taken from the grid. The set-up was kept the same and only the rotors were changed during the comparison. Fig. 5.2 shows a schematic diagram of the measurement setup. The AMB system was fed separately via UPS so that in an event of electricity blackout the bearing system would have stayed operational. This arrangement was done only for research purposes as in real applications the bearing system gets its power from the DC-link of the inverter. With this set-up the total power consumption of the bearing system could be measured. A set of measurement points was taken at zero speed and up to 835 Hz. The level of loading did not have any effect on the power Synchronous generator NORMA D 6100 Uin Iin Pin fin PC 50 Hz PC VACON CX 90 Rectifier DC link PC = = Rectifier DC link VACON CX 90 Fluke 8842A U d PC IGBT = PC NORMA D 6100 Uin Iin Pin fin Battery = Fluke 8842A U in Switch HP 5316B rpm AMB motor PC = AMB generator Uin Iin NORMA IGBT Pin fin D 6100 PC PC PC 53 Honeywell DPR 3000 Tambient Tthermocouples Fig. 5.2 Schematic diagram of the measurement setup. NORMAs use three-watt meter method. Currents are measured with shunts. Setup is controlled with a PC, using IEEE 488 bus.
Page 1 and 2: El 108 ACTA POLYTECHNICA SCANDINAVI
Page 3 and 4: PREFACE This thesis is the result o
Page 5 and 6: 5 Comparison of rotors for 60 kW 60
Page 7 and 8: LIST OF SYMBOLS a Number of paralle
Page 9 and 10: Rn Resistance of a parallel conduct
Page 11 and 12: 1 INTRODUCTION The need for high ro
Page 13 and 14: Conventional (high-speed) drive Hig
Page 15 and 16: Chapter 5 reports the comparison of
Page 17 and 18: Some penetration depth values are c
Page 19 and 20: 2.2 Stator windings for high-speeds
Page 21 and 22: ⎛ π ⎞ sin⎜ν ⎟ ⎛ π ⎞
Page 23 and 24: Table 2.3 Air gap characteristics o
Page 25 and 26: Cooling of the stator could need ax
Page 27 and 28: f sw N p = (2.9) fs The switching f
Page 29 and 30: 3 ROTOR CONSTRUCTIONS Starting from
Page 31 and 32: and eddy-currents traveling on the
Page 33 and 34: support the squirrel cage winding,
Page 35 and 36: 3.1.3 Rotor loss and friction loss
Page 37 and 38: Table 3.1 High-speed induction moto
Page 39 and 40: critical speeds are passed relative
Page 41 and 42: Table 3.2 The free-free natural fre
Page 43 and 44: Table 3.3 The free-free natural fre
Page 45 and 46: 4 COMPARISON OF ROTORS FOR 65 KW 30
Page 47 and 48: Temperature [ºC] 110 109 108 107 1
Page 49 and 50: Temperature rise [K] 120 100 80 60
Page 51: improve the laminated design, more
Page 55 and 56: As reported in Lähteenmäki et al.
Page 57 and 58: Temperature rise [K] 100 80 60 40 2
Page 61 and 62: 6. The rest of the loss is defined
Page 63 and 64: Temperature rise [K] 100 80 60 40 2
Page 65 and 66: 5.2.7 About the mechanical robustne
Page 67 and 68: 6.1 Comparison of PAM and PWM for 6
Page 69 and 70: h d = , (6.2) I I h, PAM where Ih,P
Page 71 and 72: Fig. 6.4 Phase-to-phase voltage and
Page 75 and 76: Machines loss [W] 12000 10000 8000
Page 77 and 78: considerably higher than expected.
Page 79 and 80: In order to improve the performance
Page 81 and 82: l = + , (7.2) sλs 2leλ e l wλ w
Page 83 and 84: gap of 1 mm would yield an effectiv
Page 85 and 86: Table 7.1 Calculated effective leng
Page 87 and 88: Input current [A] 170 160 150 140 1
Page 89 and 90: 8 CIRCULATORY CURRENTS IN A STATOR
Page 91 and 92: Table 8.1 Circulatory current loss
Page 93 and 94: Fig. 8.4 Strand currents in the two
Page 95 and 96: 8.2 Impedance of the circulatory cu
Page 97 and 98: Because Φ l is approximately at th
Page 99 and 100: Table 8.2 Circulatory current loss
Page 101 and 102: Power loss [W] 3500 3000 2500 2000
Page 103 and 104:
k cc 600 500 400 300 200 100 0 0 50
Page 105 and 106:
9 OPTIMIZATION OF SOLID STEEL ROTOR
Page 107 and 108:
whole solution space determined by
Page 109 and 110:
the average time saving is 39 %. Th
Page 111 and 112:
Fig. 9.3 Cross sections of the 16,
Page 113 and 114:
Height of bar slot [mm] 8 6 4 2 0 R
Page 115 and 116:
The different rotor topologies were
Page 117 and 118:
possible. The coating practically v
Page 119 and 120:
Table 9.3. Optimization results for
Page 121 and 122:
Fig. 9.11 Initial (left) and opt. (
Page 123 and 124:
high-speed induction machine. Accor
Page 125 and 126:
Foelsch K. 1936. Magnetfeld und Ind
Page 127 and 128:
Pyrhönen J. and Kurronen P. 1994.
Page 129 and 130:
APPENDIX 129
Page 131 and 132:
currents in the solid iron flow mor
Page 133 and 134:
where the C sw E is the loss coeffi
Page 135 and 136:
B. CALCULATION OF THERMAL CHARACTER
Page 137 and 138:
Axial cooling duct Frame R fr3 Stat
Page 139 and 140:
Linear equalities Ax = b, (C3) wher
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Design and Voltage Supply of High-Speed Induction - Aaltodoc

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