JaLCDOI 10.18926/15700
FullText URL Mem_Sch_Eng_OU_13_45.pdf
Author Fujitsuka Takeshi| Agusa Toru|
Abstract In this paper, the steady state operations of the squarewave inverter circuit with a series R-L load are discussed. The circuit consists of transistors and feedback diodes. The basic equation is derived from its equivalent circuit. Solving the basic equation with steady state conditions, the instaneous value of the load current i is derived. The period t(2) for which the current flows from the supply to the load and the period t(l) for which the current feedbacks through diodes from the load to the supply are calculated from (i), and the ratio of t(l) to t(2) is illustrated using power factor of fundamental wave, pf, as a variable. The ratios of transistor mean current I(tr), diode mean current I(D), supply mean current I(s) to the load current I are illustrated using pf as a variable, too. In result, each current ratios to I is shown in simple expressione. The load current can be calculated simply using the coefficient reading off the figure. In addition, it becomes clear from the figure that the load current is scarcely influenced by the harmonic voltage in less than 0.8 of pf. The ratio t(2)/(t(1)+t(2)) calculated in squarewave voltage, shows the limit of pulse width control whose out put voltage is the squarewave.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1979-03-05
Volume volume13
Start Page 45
End Page 52
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307473
JaLCDOI 10.18926/15721
FullText URL Mem_Sch_Eng_OU_12_53.pdf
Author Fujitsuka Takeshi| Agusa Toru|
Abstract In recent years, the development of a high power transistor element is proceeding. A high power inverter circuit using power transistors are finding a good number of applications in induction heating and melting. Turn off time of power transistors occupies 5-lOμs of switching characteristics. A driving method to give base inputs for a half period is widely used for a inverter circuit. But this method has the following defects, the short-circuit current flows through two transistors because the other pair transistors turn on before one pair transistors turn off. So the switching loss is increased, the maximum output and the efficiency are decreased. In this paper, a driving method to give base inputs for the less period as compared with a half period is discussed. Using this method, the foregoing defects is lost and the driving frequency is able to become higher. In addition, it become clear that the square waveform output is given using this method in the case of R-L load.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1978-02-25
Volume volume12
Start Page 53
End Page 58
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307552
JaLCDOI 10.18926/15675
FullText URL Mem_Sch_Eng_OU_4_65.pdf
Author Himei Toyoji| Fujitsuka Takeshi| Inoue Jyunichi|
Abstract As one of the wide application of thyristor circuits, the inverter has a promising future and has been investigated vigorously. On the speed control of a squirrel cage induction motor by using a variable frequency thyristor inverter, although few papers have been presented, there seems to be many problems to be solved imminently. In this paper, the stability of performance of a thyristor inverter on this theme has been confirmed and some particular points with relation to practical use also have been discussed.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1969-09-01
Volume volume4
Issue issue1
Start Page 65
End Page 73
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307309
JaLCDOI 10.18926/15620
FullText URL Mem_Sch_Eng_OU_3_131.pdf
Author Himei Toyoji| Fujitsuka Takeshi| Inoue Jyunichi| Wakabayashi Jiro|
Abstract The a-c voltage control circuit, composed of parallel connection of a SCR and a reactor, gives the similar performance as the control circuit of a back to back SCR pair. However, the control characteristics of this circuit is affected by magnetizing characteristics of reactor. In this paper, the circuit with the resistive load has been analyzed by using the approximated models of hysteresis loop of core materials, where the SCR's forward voltage drop is taken into account. The results of the analysis have revealed the facts as follows, I) The control characteristics of the a-c voltage in average value is independent on the magnetizing characteristics of reactors except in the vicinity of minimum output point. But, in effective value, it is not valid. 2) A SCR's forward voltage drop results in the reduction of not only SCR's current but also reactor's current. 3) The a-c output current does not include the d-c component, if the winding resistance of the reactor is negligible.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1968-09-01
Volume volume3
Issue issue1
Start Page 131
End Page 136
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307481
JaLCDOI 10.18926/15621
FullText URL Mem_Sch_Eng_OU_3_137.pdf
Author Himei Toyoji| Fujitsuka Takeshi| Inoue Jyunichi| Komatsubara Hitoshi| Kadowaki Masahiko|
Abstract The measurement of the dissipated energy in switching-off has been attempted to make clear the function of spark on electric contacts, which may unfortunately cause the combustible gas, such as propane gas etc, to catch fire and result in fire accidents. By utilizing the "Memoriscope" has been the meaurement carried out and the feature of this method is to provide the information on not only the amount of dissipated energy involved in one action but also on the trace of its instantaneous power which can affect catching fire delicately. Presented in this paper are the discussion of this measuring method and the measured results which are obtained experimentally in order to investigate the dependence of the energy dissipation on variety of contacts, contacts' deterioration and circuit arrangements.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1968-09-01
Volume volume3
Issue issue1
Start Page 137
End Page 142
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307412