• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A circuit arrangement for controlling the power supply to a discharge chamber (9) comprises a power transformer (1) connectable to a power supply (2), two sequentially connected rectifying means (4 and 6) connected across the chamber (9) a short-circuiting element (7) connected across one rectifying means (6) and control means (14). When the voltage across the chamber (9) surpasses a particular threshold voltage element (7) conducts. Control means (14, 15) switches off one rectifying means (6) when it senses this conduction. A second transformer (11) and a condenser (12) are connected across the chamber (9) and a thyristor 13 controlled by control means (14, 15) short circuits part of the second transformer (11) when an arc discharge in the chamber (9) occurs. The time necessary for cleaning work pieces is decreased, the power supplied differs little from the nominal power and the electric strength of the working chamber (9) is restored quickly. The productivity of the chamber (9) is increased. <IMAGE>
    公开号:SU1198132A1
    申请号:SU807771058
    申请日:1980-02-07
    公开日:1985-12-15
    发明作者:Александров Савов Светослав；Савов Минчев Минчо
    申请人:Вмеи "Ленин" (Инопредприятие)；
    IPC主号:
    专利说明:

    one
    The invention relates to devices for chemical-heat treatment of metal parts under the conditions of an electric glow discharge used in mechanical engineering.
    The closest to the invention is a device (French Patent No. 2297927, Cl. C 23 C 13/02, 1976) for the chemical-thermal treatment of metal parts under the conditions of an electric glow discharge, consisting of a working chamber with associated gas-vacuum unit, unit for cooling the chamber and the power supply unit. The anode and cathode of the working chamber are connected to an electrolytic unit, which consists of a switch, one end of which is connected to the network, and the other end is connected to the primary winding of the power transformer through a magnetic amplifier. The transformer secondary leads are connected via a switch to an upward three-phase bridge, one end of the smoothing throttle is connected to the positive terminal of the rectifying bridge, the other end is connected to ground and connected to the anode of the working chamber through a current measuring device. The minus terminal of the three-phase rectifying bridge is connected to the cathode of the working chamber. The anode of the thyristor, the cathode of which is connected to the cathode of the working chamber, is connected to the common point of the throttle and current measuring device. Parallel to the thyristor, a unit is connected to turn it off. The thyristor control circuit is connected to a control unit, the input of which is connected to a device for measuring current through the working chamber, its first output is connected to a device for turning off the thyristor, and its second input is connected to a relay to reduce the control current of the magnetic amplifier. The relay bypasses a resistor, one end of the resistors is connected to a source of control voltage of the magnetic amplifier, the other end of the resistor is connected by control of the windings of the magnetic amplifier to the other end of the control source is to Oleg Zhegoyev voltage
    The mode of operation of the plant is established by the control
    98132 -2
    current magnetic amplifier. When the adjustment range determined by the magnetic amplifier is insufficient, then the transformation ratio is changed by means of a switch.
    When increasing the current through the working chamber over a certain limit, the thyristor turns on and connects the short-circuited anode and cathode of the working chamber. At the same time, the control current of the magnetic amplifier is sharply reduced, the unit for turning off the thyristor turns it off and the control
    tS current increases. The electric glow in the working chamber is restored in 4 seconds.
    However, the full power coming from the supply chain exceeds
    2Q rated power installation, co. torus is determined by the maximum power of the glow discharge. The disadvantage of this installation is also an increase in the duration of the process of cleaning parts and pa-.
    camera at initial start. In addition, the breakdown voltage of the working chamber is restored relatively slowly, and the excitation of the glow discharge after switching off is restored with a significant delay of up to 4 s. This delay leads to a decrease in plant performance, especially at a high frequency of occurrence of arc discharge,
    The aim of the invention is to provide an installation for the chemical heat treatment of metal parts,
    The goal is achieved by the installation for the chemical-heat treatment of metal parts under the conditions of an electric glow discharge, consisting of a working chamber with an anode and a cathode with a gas-vacuum unit and a cooling unit, a power unit with a power switch, and a power transformer connected to it. , a thyristor, the control electrode of which is connected to the first output of the thyristor control unit, and the anode is connected to the anode of the working chamber, smoothing the throttle, current sensor in
    The working chamber additionally contains a reactive element, two rectifying bridges with control units, and a rectifying transformer.
    a diode and a capacitor, with one secondary winding of the power transformer connected to the first rectifier bridge directly, and the other to the second rectifying bridge through the reactive element, the positive terminal of the first bridge bridge through the current sensor in the working chamber is connected to the anode of the working chamber, and the negative terminal - with the positive terminal of the second rectifying bridge, the negative terminal of which is connected to the cathode of the working chamber through the smoothing choke, the first input of the control unit of the first A secondary bridge, the second input of which is connected to the anode of the working chamber, connected through a capacitor and the primary winding of the saturating transformer to the cathode of the working chamber, the secondary winding of the current transformer is connected to the first and second inputs of the control unit of the thyristor, the second output of which is connected to the cathode of the thyristor and the outlet the primary winding of the saturating transformer, the third input of the thyristor control unit is connected to the second output of the control unit by the second rectifying bridge, the third output of the unit A second rectifier bridge is connected to the third input of the first rectifier bridge control unit, the fourth input of which is connected to the toKa sensor in the working chamber, a diode and the fourth and fifth inputs of the thyristor control unit are connected parallel to the second rectifier bridge, and the cathode of the diode is connected to the positive terminal of the second rectifying bridge.
    The advantages of the proposed installation are that the total power supplied from the feeding circuit is not determined by the maximum power of the glow discharge. The transition from the cleaning mode of the cathode surface to the mode of chemical heat treatment does not require additional contact switches in the power circuit. The time for cleaning the cathode surface is shortened. The electrical strength of the working chamber is restored in a shorter period of time. The excitation of a glow discharge after switching off is restored to 198181 with virtually no Dani opod, thereby increasing plant performance.
    Fig. 1 shows a block diagram of an installation for the chemical heat treatment of metal parts under the conditions of an electric glow discharge; 2 is a block diagram of a thyristor control unit; Fig. 3 and block diagrams of the rectifier bridge control units.
    The installation according to the invention consists of a power transformer 1, the primary winding of which
    15 is connected to mains 2 via a power switch 3. One of the secondary windings of transformer 1 is connected to a rectifier bridge 4. Another secondary winding through reactive element 5 is connected to an additional rectifier bridge 6, and a diode is connected parallel to it 7 so that its cathode is connected to the positive terminal and the anode to
    25 negative terminal of the additional rectifying bridge 6, Negative terminal of the rectifying bridge 4 is connected with the positive terminal of the additional rectifying bridge 6,
    30 Negative terminal of the additional rectifying bridge 6 is connected via a smoothing choke 8 to the cathode of the working chamber 9. The anode of the working chamber 9 is grounded and connected through the device 10 for current measurement to the positive terminal of the rectifying bridge 4, Parallel to the anode and cathode of the working chamber 9 connected in series primary winding saturating transformer 1 1 and capacitor 12, the cathode of the thyristor 13 is connected with the removal of the primary winding of the axial transformer 11, and its anode - with the anode of the working chamber 9, Block 14 control laziness
    The 45 thyristor 13 is connected with the secondary winding of the saturating transformer 11, with the anode and cathode of the diode 7, with the control electrode and the cathode of the thyristor 13, with the control unit 15
    which is connected to the additional rectifier bridge bis unit 16 of the rectifier bridge 4, the two inputs of the control unit 16 of the rectifier bridge
    55 of the bridge 4 is connected with the anode and cathode of the working chamber 9, its third input is connected with the device 10 for measuring the current, and its output is connected with the rectifying bridge 4. The gas-vacuum unit 17 and the cooling unit 18 are connected with the working chamber 9.
    Block 14 (FIG. 2) contains elements for generating a pulse signal for switching on the thyristor 13 and switching elements included in its output circuit.
    The anode of the dynistor V is connected to the positive terminal of input 14.1, and the cathode V is connected through series-connected resistors F.. R2 and switches S, Sj to the positive terminal of output 14.4. The cathode of the Zener diode V is connected to the connection point of resistors R and R, and the anode is connected to the negative output terminal 14.5. The negative terminals of input 14.6 and output 14.5 are connected short-circuited.
    The elements V, V ,,, R and R form a signal to turn on the thyristor 13. The switching element is turned on when the voltage at input 14.2 is equal to the voltage of the additional (additional) rectifying bridge 6, is equal to zero.
    The switching element Sj is controlled by the command unit 15.
    Unit 15 (FIG. 3) contains elements for manual operation or automatic operation of the device for chemical heat treatment. The programmable setpoint P is connected via switches S to manual operation or automatic control mode to outputs 15.1, 15.2 and 15.3. The switches S and S are connected at their free ends to a voltage source (not shown in Fig. 2). The resistance Rj is grounded at its free end. In the case of manual control of switch S via output 15.1, an additional rectifying bridge 6 is turned off when the glow current through the working chamber 9 becomes greater than the current at which diode 7 becomes conductive. When the switch Sj is operated manually, output 15.2 turns off the signal to the thyristor 13 when the glow discharge current through the working chamber 9 is less than the current at which diode 7 becomes conductive.
    voltage that sets the current through the rectifying bridge 4. With automatic control
    commands for executing the algorithm are provided by a programmable setpoint R.
    Block 16 (FIG. 4) contains pulse amplifiers for switching on thyristors, a synchronizer, linearly rising voltage generators, comparators and input devices for setting the current through the rectifying bridge 4 and the magnitude, the voltage between the anode and cathode of the working chamber 9. Block action 16 is subject to typical conditions for the phase control of a thyristor rectifying bridge.
    0 Signals to turn on the thyristors in the rectifier bridge 4 are output 16.4. They are generated in the comparators A and the pulse amplifiers B. In the comparators, an amplitude comparison of one linear voltage that increases with time occurs, which is synchronized with the corresponding phase of the supply network 2 by means of a synchronizing voltage.
    device D, with one control DC. The latter takes on the value (cost) as a function of the inputs found in 16.1, 16.2 and 16.3.
    The voltage, which is applied to the input 16.1, serves as the setting of the value (magnitude) of the current through the rectifying bridge 4.
    Voltage that is applied to
    . input 16.2 is received from device 10 for measuring current. This voltage is proportional to the current through the rectifying bridge 4.
    The control DC voltage, which is applied for comparison in the comparator A, gets a value (value) determined proportionally to the integral law for controlling the current through rectifier bridge 4, depending on the value of the reference, which is fed to input 16.1 and on the value of the device signal 10 to measure the current applied to input 16.2. This action is performed by adjusting F.
    At input 16.3, a voltage is applied, which is applied to the anode and cathode of the working chamber 9. When this voltage drops to a certain value, then the trigger T switches and causes a change in the value of the control DC voltage that is supplied for comparison in pairs. This action causes an exception rectifier bridge 4, the installation operates as follows. The working chamber 9 is loaded with metal parts for processing and is hermetically closed. The switch to the installation serves the supply voltage. Through block 15, an automatic or rune mode of operation can be selected to control the entire device. After the command from block 15 to, the gas-vacuum block 17, which creates the pressure necessary for carrying out the treatment processes, after a certain period of time, begins to operate. Through a transformer 1, a voltage is applied to the rectifier bridge 4 and the additional rectifier-Horiy bridge 6, which are connected in series in such a way that the stresses of both bridges are summed up. Upon a command from the control unit 15, the additional rectifying bridge 6 is turned on and a constant voltage appears at the anode-cathode in the working chamber 9. Further, by a command from the manual (1x regulators or from the programmer, located in block 15, the rectifying bridge 4 is gradually turned on until the electric glow discharge is excited. As the current increases, the discharge voltage on the terminals of the additional synchronous bridge 6 is reduced. When the magnitude of the discharge current exceeds the short-circuit current on the additional rectifying bridge 6, then the diode 7 begins to conduct, as a result of which information is received in block 14 on switching on the secondary winding of the control saturation transformer 11, thyristor 13. At the same time, the signal received in block 15 switches off the additional high power bridge 6, and the bleeding discharge is fed only from the rectifying bridge 4, the chemical-thermal treatment of metal parts under the conditions of the electric glow discharge starts at a low pressure in the working chamber 9, a high voltage between the anode and the cathode, and a small discharge current, thereby creating conditions for cleaning the cathode surface, i.e. machined parts. Cleaning is accompanied by a frequent transition of the glow discharge to the arc. Information about this transition enters through the secondary winding of the saturating transformer 11. When the discharge current is less than the current at which diode 7 begins to conduct or the operator has given the appropriate command through block 15, the signal from the secondary winding of transformer 11 does not turn on the thyristor 13 when an arc discharge appears. In this case, an oscillatory process begins, waiting for capacitor 12 and. the primary winding of the transformer 11. This process proceeds in four stages. In the first stage, which has a duration equal to the time for reversal of the magnetic circuit of the current transformer 11, the voltage of the capacitor 12 decreases slightly. In the second stage, the capacitor 12 and the primary winding of the transformer 11 form an oscillating circuit in which the oscillation develops with a duration of one half-period, and this duration is much less than the time required to saturate the magnetic circuit of the transformer 11. During this period, the capacitor 12 is recharged, and the overcharging current The driver has a significant amplitude and flows through the arc discharge channel .. Due to this, at a certain moment the arc discharge channel sharply reduces its cross section and thus the way It promotes more intensive cleaning of machined parts. In the third stage, which has a duration equal to the time for magnetization reversal of the magnetic circuit of the transformer 11, but in the opposite direction, the voltage of the capacitor 12 decreases slightly. In the fourth stage, just as in the second stage, the oscillating process begins, but with a reverse phase. The current through the arc discharge is interrupted, the opposite voltage is applied to the working chamber 9, which begins to grow in the forward direction until a new excitation of the glow discharge.
    When the glow-discharge current is greater than the short-circuit current on the additional rectifier bridge 6, the signal from the secondary winding of the transformer 11 through the block 14 turns on the thyristor 13 at the onset of the arc discharge, if an additional command from the block 15 arrived. In this case , when a glow discharge is transferred to an arc, the difference between the voltage of a switching discharge of a switching capacitor 12 charged to a glowing discharge and the voltage of the resulting arc discharge is applied to the primary winding of a saturating transformer 11. The secondary winding supplies a turn-on signal through the block t4 to the thyristor 13. After turning on the thyristor 13, the capacitor 12 is turned on in parallel with the part of the primary winding of the step-up transformer 11. Through the part of this winding that is not covered by the thyristor 13, the back voltage is applied to the anode-cathode of the working chamber , which accelerates the interruption of the arc discharge current and leads to a more intensive restoration of its breakdown voltage. After a certain period of time, determined by the saturation time of the magnetic circuit of the Nacional transformer 11, the capacitor 12 is recharged through the primary winding of the saturating transformer 11 and the thyristor 13. After the recharging of the capacitor 12, the thyristor 1 is turned off and the anode-cathode pa6o4ieft of chamber 9 is reloaded directly. for a time also determined by the time of the magnetic circuit of the saturating transformer 11u but in the opposite direction, after which the whole voltage is again applied to the anode-cathode of the working chamber 9 and 12, which is the reverse of
    sign. This voltage begins to grow approximately linearly until the glow discharge in the working chamber 9 is again energized.
    Thus, the arc discharge, which can occur between the anode and cathode in the working chamber 9, stops almost instantly, and in the working chamber 9 for a known period of time, a voltage is applied, which changes its sign four times and contributes to its rapid recovery. voltage test.
    Thus, depending on the magnitude of the discharge current, a short-term increase in the current through a narrow, rapidly compressing arc discharge channel is undertaken in order to accelerate the cleaning of the cathode surface, i.e. workpieces, or a rapid almost instantaneous cessation of the arc discharge, which is carried out automatically or manually by means of commands from block 15,
    The transition from the cleaning mode of the processed parts by means of short-term arc discharges from a certain current level to a constant glow mode with large values of the discharge current is carried out without additional special control and occurs smoothly due to the presence of a diode 7 and a reactive element 5. By means of automatic or manually switching off the additional rectifying bridge 6 from the block 15, a reduction in the power supplied from the power supply network 2 is achieved,
    Smoothing choke 8 is designed to reduce the ripple of the discharge current and at the same time facilitates the operation of the rectifier bridge 4 during rapidly changing processes in the working chamber 9.
    J
    "}
    1 f
    H
    1sh.
    ipp
    ta
    ;
    -LBfi
    -Yt kg ffi .1
    r /
    DmoZ /5.3 l S / rofff / T6 (pus.Z
    65
    B1ho9 f.2 H SjtoHii .S j
    TV 2 phi9.4
    权利要求:
    Claims (1)
    [1]
    INSTALLATION FOR CHEMICAL AND THERMAL PROCESSING OF METAL PARTS IN CONDITIONS OF ELECTRIC · Glow discharge, consisting of a working chamber with an anode and a cathode with a gas-vacuum unit and a cooling unit connected to it, a power supply unit with a power transformer with a power supply circuit breaker, a power transformer the first output of the thyristor control unit, and the anode is connected to the anode of the working chamber, a smoothing inductor, a current sensor in the working chamber, characterized in that it further comprises a reactive the second element, two rectifier bridges with control units, a saturable transformer, a diode and a capacitor, with one secondary winding of the power transformer connected directly to the first rectifier bridge and the other to the second rectifier bridge through the reactive element, the positive terminal of the first rectifier bridge through the sensor t. the eye in the working chamber is connected to the anode of the working chamber, and the negative terminal is connected to the positive terminal of the second rectifier bridge, the negative terminal of which through the smoothing the Rossel is connected to the cathode of the working chamber, the first input of the control unit is the first rectifier bridge, the second input of which is connected to the anode of the working chamber, connected through the capacitor and the primary winding of the saturable transformer to the cathode of the working chamber, the secondary winding of the saturated transformer is connected to the first and second inputs of the control unit thyristor, the second output of which is connected to the cathode of the thyristor and the tap of the primary winding of a saturable transformer, the third input of the thyristor control unit is connected n with the second output of the control unit of the second rectifier bridge, the third output of the control unit of the second rectifier bridge is connected to the third input of the control unit of the first rectifier bridge, the fourth input of which is connected to the current sensor in the working chamber, a diode and fourth and fifth inputs of the block are connected in parallel with the second rectifier bridge thyristor control, and the cathode of the diode is connected to the positive terminal of the second rectifier bridge.
    SU „„ 1198132>
    1 11
    类似技术:
    公开号 | 公开日 | 专利标题
    SU1198132A1|1985-12-15|Installation for chemical and thermal treatment of metal or under glow discharge conditions
    KR100260654B1|2000-07-01|Apparatus of electric source
    EP0449467A1|1991-10-02|Apparatus employing a welding power supply for powering a plasma cutting torch
    US6797922B2|2004-09-28|Power supply apparatus for welder
    EP0188839B1|1989-11-29|Self-oscillating power-supply circuit
    US4792730A|1988-12-20|Circuit for interrupting arc discharge in a gas-discharge vessel
    EP0785613A2|1997-07-23|Power supply
    CA1073534A|1980-03-11|Current unit for arc welding
    EP0137401B2|1992-01-15|Heating circuit for a filament of an x-ray tube
    JPH0767328A|1995-03-10|Power supply device for switching regulator
    US4688164A|1987-08-18|Direct-voltage converter for feeding an appliance with an inductive component
    US3883714A|1975-05-13|D. C. power supply for arc welding with SCR controlling three-phase power
    US4292497A|1981-09-29|Pulsed arc welding and surfacing apparatus
    US4978829A|1990-12-18|Electric discharge machining power supply circuit
    JPH0753313B2|1995-06-07|Power control device for inverter type resistance welding machine
    EP0479196A1|1992-04-08|Power supply circuit
    JP3981208B2|2007-09-26|Arc machining power supply
    RU1773635C|1992-11-07|Plasma generator arc striking method
    SU1066049A1|1984-01-07|Device for control of electric conditions of plasma generator
    SU1072206A1|1984-02-07|Pulse voltage source
    SU1754362A1|1992-08-15|Semi-automatic welding machine
    RU1798003C|1993-02-28|Power source for electric filter
    SU1753555A1|1992-08-07|Thyristor control
    KR950001779B1|1995-03-02|Source of electric power of plasma welding torch
    SU52931A1|Device for forcing current in ion frequency converters and valve motors
    同族专利:
    公开号 | 公开日
    HU190769B|1986-11-28|
    FR2451629A1|1980-10-10|
    NO153320B|1985-11-11|
    BG29362A1|1980-11-14|
    IT1145262B|1986-11-05|
    SE440169B|1985-07-15|
    FR2451629B1|1984-12-07|
    JPS55125275A|1980-09-26|
    PL131348B1|1984-10-31|
    NO800613L|1980-09-12|
    AT365659B|1982-02-10|
    DE3007420A1|1980-09-25|
    JPS6253593B2|1987-11-11|
    CS215904B1|1982-10-29|
    GB2045553B|1983-08-17|
    DD235802A3|1986-05-21|
    NO153320C|1986-02-19|
    SE8000931L|1980-09-12|
    DE3007420C2|1984-08-30|
    YU29880A|1983-06-30|
    GR68091B|1981-10-30|
    PL222156A1|1980-11-03|
    CH644398A5|1984-07-31|
    ATA62880A|1981-06-15|
    YU41906B|1988-02-29|
    IT8047884D0|1980-02-13|
    GB2045553A|1980-10-29|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO1995017101A1|1993-12-20|1995-06-29|Nikolai Mikhailovich Ryzhov|Method of carrying out diagnostics on a process for the thermo-chemical treatment of steels and alloys in a glow discharge and a device for carrying out the said method|BE555863A|
    NL254957A|1959-08-17|
    CH561285A5|1973-02-19|1975-04-30|Berghaus Bernhard Elektrophysi|
    FR2297927B1|1975-01-17|1977-09-30|Anvar|
    FR2423914B1|1978-04-20|1980-10-31|Aizenshtein Anatoly|BG41745A1|1984-12-29|1987-08-14|Minchev|Device for discontinuing of arc dicharges in gas dicharge vessel|
    DE3514690C2|1985-04-24|1989-09-14|Aeg-Elotherm Gmbh, 5630 Remscheid, De|
    US5281321A|1991-08-20|1994-01-25|Leybold Aktiengesellschaft|Device for the suppression of arcs|
    DE4127505C2|1991-08-20|2003-05-08|Unaxis Deutschland Holding|Device for suppressing arcs in gas discharge devices|
    CH689767A5|1992-03-24|1999-10-15|Balzers Hochvakuum|Process for Werkstueckbehandlung in a Vakuumatmosphaere and vacuum treatment system.|
    DE69322404T2|1992-09-30|1999-04-29|Advanced Energy Ind Inc Fort C|TOPOGRAPHICALLY ACCURATE THIN FILM COATING SYSTEM|
    DE4239218C2|1992-11-21|2000-08-10|Leybold Ag|Arrangement for preventing flashovers in a plasma process room|
    DE4242633C2|1992-12-17|1996-11-14|Fraunhofer Ges Forschung|Process for carrying out stable low-pressure glow processes|
    US5427669A|1992-12-30|1995-06-27|Advanced Energy Industries, Inc.|Thin film DC plasma processing system|
    US5718813A|1992-12-30|1998-02-17|Advanced Energy Industries, Inc.|Enhanced reactive DC sputtering system|
    US6217717B1|1992-12-30|2001-04-17|Advanced Energy Industries, Inc.|Periodically clearing thin film plasma processing system|
    US5584972A|1995-02-01|1996-12-17|Sony Corporation|Plasma noise and arcing suppressor apparatus and method for sputter deposition|
    WO1996031899A1|1995-04-07|1996-10-10|Advanced Energy Industries, Inc.|Adjustable energy quantum thin film plasma processing system|
    US5576939A|1995-05-05|1996-11-19|Drummond; Geoffrey N.|Enhanced thin film DC plasma power supply|
    US5584974A|1995-10-20|1996-12-17|Eni|Arc control and switching element protection for pulsed dc cathode sputtering power supply|
    US5682067A|1996-06-21|1997-10-28|Sierra Applied Sciences, Inc.|Circuit for reversing polarity on electrodes|
    US5882492A|1996-06-21|1999-03-16|Sierra Applied Sciences, Inc.|A.C. plasma processing system|
    DE19651615C1|1996-12-12|1997-07-10|Fraunhofer Ges Forschung|Sputter coating to produce carbon layer for e.g. magnetic heads|
    US5889391A|1997-11-07|1999-03-30|Sierra Applied Sciences, Inc.|Power supply having combined regulator and pulsing circuits|
    US5990668A|1997-11-07|1999-11-23|Sierra Applied Sciences, Inc.|A.C. power supply having combined regulator and pulsing circuits|
    US6011704A|1997-11-07|2000-01-04|Sierra Applied Sciences, Inc.|Auto-ranging power supply|
    US5910886A|1997-11-07|1999-06-08|Sierra Applied Sciences, Inc.|Phase-shift power supply|
    US5993613A|1997-11-07|1999-11-30|Sierra Applied Sciences, Inc.|Method and apparatus for periodic polarity reversal during an active state|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    BG7943198A|BG29362A1|1979-03-11|1979-03-11|Apparatus for chemical- thermal processing of matal articles in the condition of electrical smouldering charge|
    [返回顶部]