baber/WOPTO huggingface dataset:
Patent KR-860000127-B1 (KR)
Title: Electromagnetic thin strip casting apparatus
Inventor: PRYOR MICHAEL J
IPC: B22D11/01
Filed: 1985-03-21
Granted: 1986-02-26
Abstract: An appts. for casting a thin strip of metal, alloy or metalloid comprises at least one single-turn inductor(11) with a first part(26) for shaping the melt into a strip and an upstream second part(31), contained solely by the electromagnetic field. The second part defines a air space containment zone with a crosssectional area that is at least five times that defined by the first part, so that the area of the sump top is much greater than the strip area. There are pref. two mutually isolated and independently powered single-turn inductors. The strip is pref. no thicker than 0.75 inch and a current applicator frequency control provides a current penetration depth in the melt of not more than 1/4 strip thickness.
Patent KR-870001789-B1 (KR)
Title: Black-white channel double scanning apparatus
Inventor: PARK JONG-SOK
IPC: H04N3/14
Filed: 1985-04-11
Granted: 1987-10-10
Abstract: This invensions present a unit which can double the number of scanning lines and especially can be used for both the black and white T.V. and color T.V. Therefore the number of scanning line is 1050(525X2), but transmitted T.V. signals have 525 scanning lines. The other 525 scanning lines are sbtained reusing those from the transmitted signals.  The over views of this invension are described like this.  The T.V. signals travel tuner/ intermediate frequency and detector.  And then at image and voice signal processor, the voice signals is transmitted to speaker and image signals convert to digital form through A/D converter.  And the digital signals are processed by the scanning line doubling unit vertically and horizontally.
Patent KR-920003901-B1 (KR)
Inventor: GOETZ NORBERT
IPC: C07D335/02
Filed: 1985-04-24
Granted: 1992-05-18
Abstract: 내용 없음.
Patent KR-930004175-B1 (KR)
Inventor: SATO NOBUYUKI
IPC: G11C16/20
Filed: 1985-05-23
Granted: 1993-05-21
Abstract: 내용 없음.
Patent KR-920002616-B1 (KR)
Inventor: COLLBELL JERALD E
IPC: C08G65/10
Filed: 1985-05-30
Granted: 1992-03-30
Abstract: 내용 없음.
Patent KR-900001713-B1 (KR)
Title: Television camera tube device
Inventor: MARUYAMA MASANORI
IPC: H01J29/48
Filed: 1985-07-15
Granted: 1990-03-19
Abstract: An electron gun comprises a cathode electrode for emission of an electron beam and two grid electrodes respectively having apertures for controlling the diameter of the beam.  The aperture of the second grid electrode is smallr than that of the first.  The first electrode is supplied with a positive voltage relative to the cathode electrode.  The second grid electrode is applied with a second positive-voltage relative to the cathode which is higher than that applied to the first.  The first positive voltage is such that the beam passing through the first aperture has a laminal flow configuration.
Patent KR-880002691-B1 (KR)
Title: Floppy disk control apparatus
Inventor: KIM JIN-HON
IPC: G06F13/00
Filed: 1985-10-04
Granted: 1988-12-20
Abstract: The circuit for controlling a mini floppy disc consists of a selecting circuit for motor driver, a data processing circuit, and a request mode circuit.  The motor driver is selected by an output transistor (5) but if the motor driving signal from a NOR gate (G3) is not applied to an enable port (EN) of a selection converter (14), all outputs of the converter (14) are turned to high state so that the selection of the motor driver is not performed. The data processing circuit includes a data processing IC which has data seperation and compensation functions.  The request mode circuit includes a flip-flop, a floppy disc controller, and buffers (EB1, EB2).
Patent KR-940000501-B1 (KR)
Inventor: ISHIJIMA AKIRA
IPC: B29C37/02
Filed: 1985-11-30
Granted: 1994-01-21
Abstract: 내용 없음.
Patent KR-920008944-B1 (KR)
Title: Electrical connection device intended to be placed through the wall of a direct-current metall urgical furnace
Inventor: MICHELET JACQUES
IPC: H05B7/11
Filed: 1986-02-11
Granted: 1992-10-12
Abstract: The device consists principally of: - an internal part crossing the wall of the furnace and comprising a metal core 7 extended by a cooled end-piece 10 which is integral with it, the free end of the core being in contact with the melting metal mass contained in the furnace, - a sleeve 11, in a heat-conducting material, cooled by circulating a cooling fluid, and surrounding the core 7, - and means 29 of connecting the metal core 7 to an electrical supply. The device furthermore has a separation space 12 made between the sleeve 11 and the metal core 7, and an elastic fastening system 33, 34, 35, tending to return the said core 7 to its given initial position upon setting-up. The device according to the invention applies advantageously to metallurgical direct current furnaces in the guise of hearth electrode. <IMAGE>
Patent KR-930002279-B1 (KR)
Inventor: MIKITA YOSHIHIRO
IPC: C07D241/38
Filed: 1986-03-28
Granted: 1993-03-27
Abstract: 내용 없음.
Patent KR-900002995-B1 (KR)
Title: Magnetic tape and the method of adjusting of magnetic recording device
Inventor: SIRAYANAKI DATSUYA
IPC: G11B5/02
Filed: 1986-07-31
Granted: 1990-05-04
Abstract: The method is for adjusting the apparatus by recording the information of differnet kinds at different levels in different parts of an inclined track.  A magnetic tape (1) is guided by a guide (2) and wound around a rotary drum (3) to which rotary heads (4,5) have been attached.  Also video information is recorded in a part corresponding to an angle (A1) and PCM audio information is recorded in a part corresponding to an angle (A2). Also the PCM audio information is recorded at a small level than that of the video information.  In this state, recording and reproducion are executed by switching the rotary heads (4,5) by a switching pulse.
Patent KR-920006427-B1 (KR)
Inventor: SHIBATA DETSUO
IPC: E03F5/10
Filed: 1987-02-25
Granted: 1992-08-06
Abstract: 내용 없음.
Patent KR-900004983-B1 (KR)
Title: Method for containing multipart composition
Inventor: USAMI IKUZO
IPC: B65B5/02
Filed: 1987-04-15
Granted: 1990-07-16
Abstract: A cartridge container being used to store and then mix two jellied components comprises a mixing nozzle communicating with the interior of a cylindrical body at one end, and an urging lid movably insertable in the other end. The body is separated into spaces by a membrane and a component is stored in each space. On removing the membrane, the components mix for discharge from a nozzle which contains a blade.
Patent KR-950006233-B1 (KR)
Title: Sync. separator
Inventor: BALABAN ALVIN R
IPC: H04N5/08
Filed: 1987-04-29
Granted: 1995-06-12
Abstract: A sync separator detects, in a corresponding part of the waveform of a video signal (100), the occurrence of the trailing edge of a corresponding sync pulse, in accordance with the rate of change of the video signal. Information obtained from the sync tip and the back porch portions of the corresponding sync pulse is used for generating a slice level signal (SL). A comparator (20) responsive to the slice level signal separates a sync signal (100a) from the video signal (100).
Patent KR-890003109-B1 (KR)
Title: Heat exchanger
Inventor: KOTAKA IKUO
IPC: F28D15/02
Filed: 1987-05-27
Granted: 1989-08-22
Abstract: Heat pipe apparatus in a heat exchanger has a condenser pipe group (6,14,20) located away from the lower end of an evaporative pipe group (1,12,16).  And in the fluid to be heated, a passage for working medium connects the pipe groups.  A bubble generator is located in a by-pass passage (42) through which part of the heating fluid is branched to forcedly circulate through the first passage. Flow through the by-pass passage (42) is pref. regulated.
Patent KR-910000460-B1 (KR)
Inventor: TAKAHASI MASAYUKI
IPC: C12N15/27
Filed: 1987-09-17
Granted: 1991-01-25
Abstract: 내용 없음.
Patent KR-900002795-B1 (KR)
Title: The high-speed searching method of the optical disc driver
Inventor: KIM HAE-KWANG
IPC: G11B7/00
Filed: 1987-09-25
Granted: 1990-04-30
Abstract: The method for reducing the search time uses a step motor (7) for long seek and a tracking coil (L) for short seek.  The data read by an optical head (6) is stored in a buffer memory (6) through a demodulator (4).  The step motor linked with the head is drived until a track counter (2) counts up to zero and the present position is calculated.  Then the step motor drives the head to the position at which the tracking coil can be worked.  Then, the track counter is preset and the tracking coil is drived until the track counter counts up to zero.  Then the seek operation is performed by driving the focusing and driving servos.
Patent KR-900005393-B1 (KR)
Title: Composition of ceramic-coat and paint agent
Inventor: CHON HON-SAENG
IPC: C09D1/00
Filed: 1987-09-25
Granted: 1990-07-28
Abstract: The ceramic coating material radiating infrared rays consists of 6-10 wt.% SiO2, 18-22 wt.% MnO2, 48-52 wt.% silica sol as binder and 14-16 wt.% solution of aluminium phosphate, or consists of 20-26 wt.% MnO2, 6-10 wt.% MnO2, 20-24 wt.% silica sol as binder and 42-48 wt.% solution of potassium silicate. The composition is prepared by sieving SiO2 and MnO2, mixing the remainder components, and ball- milling for more than 24 hours. The meterial has a good refractory and adhesion and resistance of heat shock.
Patent KR-900002526-B1 (KR)
Title: Preparation method of optical fiber preform
Inventor: YOSHIDA GIMINOBU
IPC: C03B20/00
Filed: 1987-10-14
Granted: 1990-04-20
Abstract: In the production of a preform for an optical glass fibre a glass rod (1) is introduced into one end of a glass tube (2) while gas is supplied to the other end and exhausted through the annular gap between rod and tube.  The assembly is then heated to collapse the tube onto the rod.  The rod is introduced vertically into the upper end of the tube and the gas is nitrogen or clean dry air. The rod may have a conical end which engages a construction at the lower end of the tube.
Patent KR-910000648-B1 (KR)
Title: Stopping circuit of video display and sound in case of reproducing end for digital vtr
Inventor: KIM BYUNG-JIN
IPC: G11B20/24
Filed: 1987-11-04
Granted: 1991-01-31
Abstract: A screen/voice still circuit for a digital VTR uses  a  frame memory (35). One video signal from a video signal provider (10) is provided to the  frame  memory  through  and  A/D  converter,  two horizontal delays and a buffer. A phase locked loop  (40)  detects the burst signal from  the  video  signal  provider  and  provides clocks to the A/D converter and two horizontal delays.  A  PLL  is also connected to a horizontal write address terminal of the frame memory. An other video signal is provided to  a  vertical  address terminal of the frame memory  through  a  sync.  dividing  circuit (50), a phase sync. loop (55) and  a  vertical  address  generator (60). A monostable multivibrator (65)  is  connected  to  a  write enable terminal  of  the  frame  memory  and  controls  a   voice controller (75).
Patent KR-900003112-B1 (KR)
Title: Method for manufacturing a good water-repellent synthetic swede made by woven or knitted fabric
Inventor: AN BYUNG-HUN
IPC: D06N3/08
Filed: 1987-12-19
Granted: 1990-05-08
Abstract: A good water-repellent artificial swed is prepd. by treating a substrate fabric with the polyurethane resin soln. comprising polyurethane resin, cross linking agent and catalyst; drying and buffing; then treating with a water-repellent agent and curing. In the process, the condensation-reacting silicone based cpd. of formula (I) is add-mixed into the polyurethane resin soln. In formula, R = - H, CnH2n+1 (1<n<10); R' = CnH2n+1 (1<n<10); R" = -CH, CnH2n+1 (1<n<10); X,Y = 200-2000 integer. Pref. the cpd. (I) is 5-30 wt. % w.r.t. the polyurethane resin.
Patent KR-910003532-B1 (KR)
Inventor: SHIOYA MAKOTO
IPC: G01C3/06
Filed: 1987-12-30
Granted: 1991-06-04
Abstract: 내용 없음.
Patent KR-900004576-B1 (KR)
Title: Continous dryer of laver
Inventor: HONG SOON-GI
IPC: A23L17/60
Filed: 1988-02-08
Granted: 1990-06-30
Abstract: Automatic continous dryer of laver has a lower temperature dry room lower temperature and a main dry room for multidirectional hot air drying, gives a good guality of drying laver. The drying process consists of washing, laying on reed screen, dehydration, drying, and separation. The dryer includes washer (3), laying apparatus (4), dehydrator (5), separator (6), and is moved continuously by feed chain with protrusion (1). Dehydrator has partitioned dry room (7) with hot air generator (13) changing air direction, and predry room (8) with elastic chains (11)(11'), auxiliary chain (12).
Patent KR-900006858-B1 (KR)
Title: Head-feeding type threshing apparatus
Inventor: NAKAJIMA SINROKU
IPC: A01F12/00
Filed: 1988-03-25
Granted: 1990-09-22
Abstract: The apparatus has serveral rotary members arranged parallel to the direction of crops with rotary shafts and projecting radial teeth. The threshing apparatus comprises several rotary members (3) each with several threshing teeth. The rotary members are rotatable on parallel axes (p) and extend in the direction of movement of the reaped crop. The reaped crop is fed in by a feed chain (1) and placed in a straight posture in a direction normal to the axes when in contact with rotary members. The threshing teeth of adjacent rotary members have addendum circles overlapping one another in a direction parallel to the axes.
Patent KR-940009871-B1 (KR)
Title: Preparation of superconducting oxides and oxide-metal compositions
Inventor: YUREK GREGORY J
IPC: H01L39/12
Filed: 1988-03-26
Granted: 1994-10-18
Abstract: A superconducting oxide-metal composite, comprising a superconducting oxide phase and a noble metal phase to provide said composite with improved mechanical properties. Said superconducting oxide phase being present almost continuously throughout the composite and said noble metal is precipitated in the oxide phase as finely divided substantially pure metal phase and is intimately mixed in the composite for acting as a skeleton in the composite to improve the ductility and strength of said composite.
Patent KR-910009753-B1 (KR)
Inventor: KOMURASAKI SADOSHI
IPC: F02P5/153
Filed: 1988-04-06
Granted: 1991-11-29
Abstract: 내용 없음.
Patent KR-920004033-B1 (KR)
Inventor: SATTO MASAYOSHI
IPC: H02M7/217
Filed: 1988-04-08
Granted: 1992-05-22
Abstract: 내용 없음.
Patent KR-960016305-B1 (KR)
Inventor: ZARLING JOYCE M
IPC: C07K16/00
Filed: 1988-05-04
Granted: 1996-12-09
Abstract: 요약 없음.
Patent KR-960008944-B1 (KR)
Title: Silica-bound calcium-containing zeolite a granulate
Inventor: PUPPE LOTHAR
IPC: B01J20/18
Filed: 1988-06-04
Granted: 1996-07-10
Abstract: Granulated Ca-containing zeolite A for oxygen enrichment from air contains SiO2 as binder, and the zeolite fraction has no CO3 structures on the exchanged calcium cations.
Patent KR-910009315-B1 (KR)
Inventor: SIMADA GIZUSI
IPC: H01L21/28
Filed: 1988-08-17
Granted: 1991-11-09
Abstract: 내용 없음.
Patent KR-910006036-B1 (KR)
Inventor: YOSHIZUMI AKIRA
IPC: C08L55/02
Filed: 1988-09-13
Granted: 1991-08-12
Abstract: 내용 없음.
Patent KR-910008367-B1 (KR)
Inventor: GRZYWA EDWARD
IPC: C07C39/16
Filed: 1988-10-07
Granted: 1991-10-12
Abstract: 내용 없음.
Patent KR-920003903-B1 (KR)
Title: Resin composition which in low pollution and combustion retardant
Inventor: CHEON YUN-TAEK
IPC: C08L23/00
Filed: 1988-12-26
Granted: 1992-05-18
Abstract: A fire retardant polyolefin resin composition  comprises  100 wt. pts.  of  base  polymer  (1),  0.01-5.0  wt.  pts.  of   high temperature antioxidant (2), 1-30 wt. pts. of red phosphorus  (3), 1- 30 wt. pts. of melamine (4) and 10-150 wt. pts. of metal hydrate (5). The polymer (1) is low density polyethylen having 0.875-0.935 density or its mixture. The mixture is selected from polyethylene, ethylene olefin  copolymer,  ethylene  vinylacetate  copolymer  or ethylene ethylacrylate copolymer. The resin composion has  a  good mechanical property and  moldability,  and  is  used  for  coating electric wires.
Patent KR-940009903-B1 (KR)
Title: Process and device for producing tubular bodies
Inventor: UEBEREGGER HENRY
IPC: B29C65/32
Filed: 1987-10-07
Granted: 1994-10-18
Abstract: A foil strip composed of several layers is continually rolled up around an axis extending in its longitudinal direction to form a tubular body (38) in such a way that the two edges (42, 44) overlap. To effect welding, the overlapping edges are pressed together between two strips (16, 18) which are driven in a circulating manner in the longitudinal direction. The inner strip (16) which passes inside the tubular body (38) is provided with a longitudinal groove (40) which at least partly receives the region of the overlapping edges (42, 44). The longitudinal groove (40) forms the region of the seam of the tubular body (38) which is facing inward, and prevents the plastic material which is liquefied for welding from expanding as a result of the application pressure. In this way it is ensured that the material of the two edges (42, 44) is fully welded together, so that no pressed-out edge regions of liquid material cool prematurely and therefore do not adhere to the opposed material layer.
Patent KR-960006187-B1 (KR)
Inventor: HEED KAI
IPC: F16L55/124
Filed: 1987-12-03
Granted: 1996-05-09
Abstract: 내용 없음.
Patent KR-960012056-B1 (KR)
Inventor: NARUKE KIYOMI
IPC: H01L29/792
Filed: 1989-03-30
Granted: 1996-09-11
Abstract: 내용없음
Patent KR-0127909-B1 (KR)
Inventor: SAKO YOICHIRO
IPC: G11B20/10
Filed: 1989-06-21
Granted: 1998-04-01
Abstract: 내용 없음.
Patent KR-920003651-B1 (KR)
Title: Background screen processing circuit of multi-screen display
Inventor: YEO KWON
IPC: H04N5/265
Filed: 1989-06-30
Granted: 1992-05-06
Abstract: The circuit includes a  microprocessor  (10)  for  outputting multi- picture signals, and a memory (50)  for  storing  brightness signals and color signals. A counter means (21) counts  a  certain number in synchronization with the multi-picture  signals,  and  a control signal generating means (24)  generates  background  color converting signals and data clear signals. A decoding  means  (22) outputs signals in such a manner as to output  incremented  number of sub- pictures each time when the counting means (21) upcounts. A latching means (31) latches first and second brightness and  color signals to output them to the memory (50). A color selecting means (32) adjusts the color and brightness of the background picture.
Patent KR-0128159-B1 (KR)
Inventor: MULLEN WILLIAM HENRY
IPC: C12Q1/00
Filed: 1989-07-28
Granted: 1998-04-01
Abstract: 내용없음
Patent KR-920007377-B1 (KR)
Inventor: KITAMURA SHIGENOBU
IPC: H02J7/00
Filed: 1989-11-30
Granted: 1992-08-31
Abstract: 내용 없음.
Patent KR-950000727-B1 (KR)
Title: Nylon-6 fiber and manufacturing method thereof
Inventor: KIM KI-SU
IPC: D01F1/02
Filed: 1989-12-21
Granted: 1995-01-28
Abstract: The high strength polycaproamide fiber having at least 8.0 g/d tenacity, 15-30 % elongation, at least 25 g/d initial modulus, 1-4 % (150 deg.C × 30 min) dry shrinkage ratio, at least 0.91 crystalline orientation degree and at most 0.70 amorphous orientation degree is produced by (a) adding a 2-mercapto-4,5,6,7- tetrahydor-benziimidazole (HMBI), a complex salt of the HMBI and a copper iodide (CuI) or a complex salt of a 2-mercaptobanziimidazole and the CuI to a high polymerization degree polyamide comprising at least 95 mol% ε-caproamide unit, (b) spinning the mixture at least 1500 m/min, (c) passing a filament through a heating zone and a cooling zone, (d) heating it with 400-1000 deg.C steam, and (e) taking it up on the take-up roller. The nylon-6 fiber has a good dimensional stability and fatigue resistance.
Patent KR-960000729-B1 (KR)
Inventor: HEYES PETER JOHN
IPC: B32B15/08
Filed: 1988-10-12
Granted: 1996-01-12
Abstract: 내용 없음.
Patent KR-940010715-B1 (KR)
Inventor: KITAMURA ATSUSHI
IPC: B60R21/233
Filed: 1988-12-10
Granted: 1994-10-24
Abstract: 내용 없음.
Patent KR-920002868-B1 (KR)
Title: Novel cephalosporin derivatives
Inventor: KIM YONG-JOO
IPC: A61K31/545
Filed: 1990-02-05
Granted: 1992-04-06
Abstract: Cephalosporin derivs. of formula (I), their  pharmaceutically acceptable non-toxic salts and their physiologically  hydrolyzable esters and solvates are new. In (I), R1=C1-4 alkyl, C3-4  alkenyl, C3-4 alkynyl or -C(Ra)(Rb)COOH; Ra and  Rb=H  or  C1-4  alkyl;  or CRaRb=C3-7  cycloalkyl;  R2=C1-4   alkyl,   C3-4   alkenyl,   C3-7 cycloalkyl or amino; R3=C1-3 alkyl. Cpds. (I) exibit antibacterial activity  against  Gram-positive  and  -negative  bacteria   (esp. Pseudomonas spp.). (I) have a good stability to beta-lactamase.
Patent KR-0133937-B1 (KR)
Inventor: MALKI JEHUDA
IPC: C11D17/04
Filed: 1990-02-22
Granted: 1998-04-18
Abstract: 내용없음.
Patent KR-0143778-B1 (KR)
Title: Bengo-1,2,3-thiadiagole-7-carboxylic acid ester and process forthe preparation thereof
Inventor: KUNZ WALTER
IPC: C07F7/10
Filed: 1990-02-21
Granted: 1998-07-15
Abstract: Novel benzo-1,2,3-thiadiazole-7-carboxylic acid esters of the formula   <IMAGE>  in which the substituents have the following meanings:  Y represents oxygen or sulphur; Q1 and Q2 independently of one another represent hydrogen or halogen; R1 and R2 independently of one another represent hydrogen or C1-C4-alkyl; X1 represents hydrogen, halogen, C1-C4-alkyl, trifluoromethyl, C1-C3-alkyl, C1-C2-alkoxy which is substituted in the alkyl moiety by halogen, or represents nitro, cyano, dimethylamino, phenyl, phenoxy, or represents phenyl or phenoxy, each of which is substituted by halogen and/or C1-C2-alkyl and/or C1-C2-alkoxy;  X2 represents hydrogen, halogen or methyl;  X3 represents hydrogen or halogen;  and  A represents the bridge members <IMAGE> carbonyl, ethenylene or ethynylene;  where R3 represents C1-C6-alkyl, C3-C6-alkenyl, hydroxy, C1-C6-alkoxy, O-C(O)-C1-C4-alkyl, carboxyl, COOC1-C4-alkyl, cyano or hydrogen, with the proviso that, in the event that R3 denotes hydrogen, R1, R2 or R4 is not simultaneously hydrogen; R4 represents C1-C6-alkyl, C1-C6-alkoxy or hydrogen, with the proviso that, in the event that R4 denotes hydrogen, R1, R2 or R3 is not simultaneously hydrogen; R5 represents C1-C6-alkyl, C1-C6-cycloalkyl, C1-C6-alkoxy, phenyl, or represents phenyl which is substituted by halogen or methoxy;  R6 reprsents C1-C6-alkyl or C1-C6-alkoxy;  or furthermore represents the bridge member <IMAGE> which in conjunction also represents a saturated or unsaturated 3-7-membered carbocycle W1 or a saturated or unsaturated 5-7-membered heterocycle W2 having 1 or 2 hetero atoms which denote either oxygen, sulphur or nitrogen;  or the bridge member <IMAGE> which in conjunction denotes a saturated or unsaturated 3- to 7-membered heterocycle W3 having not more than 2 oxygen or sulphur atoms as further hetero atoms. The novel active substances have plant-protecting properties and are suitable, in particular, for the preventive protection of plants against the attack of phytopathogenic microorganisms such as fungi, bacteria and viruses.
Patent KR-0140098-B1 (KR)
Inventor: AKUTSU MITSUO
IPC: B41M5/337
Filed: 1990-07-19
Granted: 1998-06-15
Abstract: 내용 없음.
Patent KR-940003311-B1 (KR)
Inventor: CHEKERINI MASIMO
IPC: F04C29/00
Filed: 1990-08-10
Granted: 1994-04-20
Abstract: 내용 없음.
Patent KR-930004026-B1 (KR)
Title: Driving circuit for inverter
Inventor: SONG JIN-KU
IPC: H02P27/08
Filed: 1990-10-13
Granted: 1993-05-19
Abstract: The circuit for using an insulated  gate  bipolar  transistor (IGBT) to improve the switching speed and regular output comprises a rectifier (1) for three phase AC power source, an  inverter  (2) for receiving the rectified voltage to provide three-phase driving voltage to an induction motor (IM) according  to  a  gate  control signal, a CPU (4) for processing the speed command signal inputted through an I/O unit (3) to output a control  signal  according  to the speed command, a gate array (5) for receiving control  signals from the CPU (4) and a protection circuit (6) to  output  a  pulse width modulating (PWM) signal, and a gate  control  unit  (7)  for outputting the gate control signal to the inverter  (2)  according to the PWM signal.