JPH09108944A - Power unit for electric discharge machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent increase of demand of constant voltage source provided on respective machining current sources, even if parallel quantity of machining current source increases, by providing a constant voltage power consumption body, which is operated by lower voltage than the constant voltage power consumption body provided on respective machining current sources, between terminals at a midway junction. SOLUTION: Machining current sources 401 to 40n respectively include first constant voltage power consumption bodies 1161 to 116n operated by a diode 114 and a constant voltage source 115 connected in series. A second constant voltage power consumption body 1 of voltage lower than the first constant voltage power consumption body 401 to 40n is connected between midway junctions E, W. When parallel numbers of machining current sources 401 to 40n increases, energy consumed only by the second constant voltage power consumption body 1 increase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for an electric discharge machine which supplies machining power between an electrode provided in a machining fluid and a workpiece.

[0002]

2. Description of the Related Art As a conventional technique, FIG.
It shows a power supply device for an electric discharge machine disclosed in Japanese Patent No. 208316. A power supply device for an electric discharge machine includes a constant current supply unit 100 configured by a switching element 102 that is opened and closed by a gate drive circuit 101, diodes 103 and 104, a reactor 105, and the like, to which direct current power is supplied from a power supply Eo, and a constant current supply unit. It is connected to the latter part of section 100,
Constant voltage power consuming body 11 by a switching element 112 opened / closed by a gate drive circuit 111, a diode 113, and a series connection body of a diode 114 and a constant voltage source 115.
6 and the like, and has an output current interruption unit 110 that supplies machining power to the electrode 120 and the workpiece Wr.

In this electric power supply device for an electric discharge machine, the gate drive circuit 101 of the constant current supply section 100 operates in response to an output current command from a current command section (not shown) to turn on / off the switching element 102. The constant current supply unit 10 is turned on / off by turning on / off the switching element 102.
The output value of 0 is controlled to the current value according to the output current command,
The switching element 112 is turned on and off by operating the gate drive circuit 111 of the output current cutoff unit 110 according to a discharge command from a discharge command unit (not shown), and supplies a machining current to the electrode 120 and the workpiece Wr. The interruption is made.

When the switching element 112 of the output current interruption section 110 is turned on and the current output from the constant current supply section 100 flows through the switching element 112, the diode 113, the electrode 120, and the workpiece Wr. hand,
When the switching element 112 is turned off, the energy stored in the inductance of the wiring connected to the electrode 120 and the workpiece Wr is converted into a constant voltage power consumption body by a voltage source 113, a series connection body of a diode 114 and a constant voltage source 115. 1
It is consumed by passing through 16 and the machining current is cut off sharply.

The energy consumed by the constant voltage source 115 increases as the machining current increases and the wiring inductance increases, and the power consumption increases in proportion to the machining frequency.

Actually, when the processing current is 60 A, the wiring inductance is 2 μH, and the voltage of the constant voltage source 115 is 60 V, the energy consumed by the constant voltage source 115 is about 46 W at the processing frequency of 20 KHz. Therefore, when there is only one machining current source, if a constant voltage source 115 that withstands power consumption of about 50 W is provided, it can be used in actual electric discharge machining.

As shown in FIG. 6, the constant voltage source 115 includes a capacitor 130, a voltage drive type transistor 131 such as a MOSFET, a Zener diode 132, and a resistance element 133.
This is disclosed in Japanese Patent Laid-Open No. 7-68417.

The constant voltage source 115 includes a capacitor 130.
The electric charge stored in the transistor 1
Power is consumed by 31. In reality, the transistor 131 is provided with a radiator to cool and dissipate heat. The larger the power consumption of the transistor 131, the larger the radiator required.

FIG. 7 shows, as another conventional example, a plurality of power supply devices for electric discharge machines (hereinafter referred to as machining current sources) 40 ₁ to 40 n, which are composed of a constant current supply unit 100 and an output current interruption unit, are connected in parallel. It shows a power supply device for electric discharge machine
This is disclosed in JP-A-5-208316. In this power supply device for an electric discharge machine, a machining current source 40 ₁
~40n the respective output conductor terminals 117, 118 are close at the same length with each other (output line) 41 ₁ ~41n by a common intermediate connection points E, is connected to the W, the intermediate connection point E, W
Is the common wiring 42, 43 and the electrode 120 and the workpiece W.
It is connected to r, and with this configuration, a large current can be supplied to the electrode 120 and the workpiece Wr, and the workpiece can be electric discharge machined at high speed.

In the power supply device for an electric discharge machine, each of the output lines 41 _{1 to} 41 n has a corresponding machining current source 40 _{1 to} 40 n.
Wiring current L _{10 to} Ln ₀
Energy is accumulated in the wiring, and the entire current flows through the common wirings 42 and 43, so that energy is stored in the wiring inductance L ₁ . Therefore, when the machining current sources 40 ₁ to 40 n are simultaneously turned on and off to perform electric discharge machining, the energy accumulated in the inductance of the wiring when the discharge current is turned off causes the constant voltage source 11 in each of the machining current sources 40 _{1 to} 40 n for the electric discharge machine.
Absorbed by 5. The energy consumed by the constant voltage source 115 is proportional to the frequency of electric discharge machining, and sharply increases in accordance with the number of machining current source power supply devices 40 _{1 to} 40 n connected in parallel.

FIGS. 8 (a) to 8 (d) show the machining current sources 40 ₁ to 6 in the power supply device for an electric discharge machine shown in FIG.
When the current of 0 A and the current of 80 A is output to each of the machining current sources 40 ₂ to 40 ₈ , the parallel number and the constant voltage source 115
Represents the relationship of energy consumed in. FIG.
In (a) to (d), a1, b1, c1, and d1 respectively represent the energy consumption of the constant voltage power consumption body 116 of the machining current source 40 ₁ , and a2, b2, c2, and d2 respectively represent the machining current source 4
The energy consumption of the constant voltage power consumer 116 of 0 _{2 to 4} n is shown.

Processing current source 40₁Fixed when operated by itself
The power consumption of the voltage source 115 is a1 and is 20 KHz.
Even it is about 46W. However, the machining current source 40₁When
40 _TwoWhen two units are operated, the machining current source 40_TwoConstant current
The power consumption of the pressure source 115 is, as indicated by b2,
It becomes 5.2 mj, and this constant voltage source 115 has 104 W
Power is consumed. Also, the number of parallels has been increased to 4 and 8 units.
Then, the power consumption of the constant voltage source 115 is c2, d2.
Further increase, as indicated by. This is a common distribution
Since the entire current flows through the lines 42, 43, the
Energy that is proportional to the square of the current is stored in the inductance.
This is each processing current source 40₁-40n constant voltage source 11
Since the power consumption is 5, the power consumption becomes large.

[0013]

Since the conventional power supply device for an electric discharge machine is constructed as described above, the power consumption of the constant voltage source 115 when the machining current source is operated by one unit as described above. 50 W at 20 KHz is sufficient, but if several machining current sources are connected in parallel, the power consumption of the constant voltage source 115 exceeds 100 W even if only two machining current sources are connected. If the allowable power consumption of the constant voltage source 115 is set to be large, there is a problem that the device becomes large and the cost becomes high.

The present invention has been made in order to solve the above problems, and the power consumption of the constant voltage source provided in each machining current source increases even if the number of parallel machining current sources is increased. It is an object of the present invention to provide an improved power supply device for an electric discharge machine in which there is no need to set the allowable power consumption of the constant voltage source to a large value.

[0015]

In order to achieve the above-mentioned object, in a power supply device of an electric discharge machine according to the present invention, a plurality of machining current sources are connected by output lines at a common intermediate connection point, and an intermediate connection is made. In a power supply device of an electric discharge machine in which points are connected to an electrode and a workpiece by common wiring, a first constant voltage power consumption body by a series connection body of a diode and a constant voltage source provided in each machining current source. And a second constant voltage power consuming body having a voltage lower than that of the first constant voltage power consuming body and configured by a series connection body of a diode and a constant voltage source provided between the terminals of the intermediate connection point. ing.

In the power supply device of the electric discharge machine according to the present invention, when the number of connected machining current sources increases, the second constant voltage power consuming body consumes energy due to the wiring inductance when the power is cut off, and the number of connected machining current sources is increased. The power consumption of the first constant-voltage power consumer does not increase even if the power consumption increases.

A power supply device for an electric discharge machine according to the next invention
Is the inductance L of the common wiring ₁Is like
The second constant voltage power consumer that is set to a value
The voltage of the constant voltage source of is set to zero and only the diode is connected.
It is what has been.

L ₁ = {(discharge voltage) × (inductance of output line)} / {(voltage of constant voltage source of first constant voltage power consumer) × (number of parallels)} of the electric discharge machine according to the present invention In the power supply device, the energy of the inductance L ₁ of the common wiring is consumed as a part of the processing power, and the second constant voltage power consumer consumes almost no power.

In a power supply device for an electric discharge machine according to the next invention, a plurality of machining current sources are connected by output lines at a common intermediate connection point, and the intermediate connection points are connected by common wiring to an electrode and a workpiece. In a power supply device of an electric discharge machine, a diode provided between each machining current source and a first constant-voltage power consumption body by a series connection body of the constant-voltage source and a diode provided between the output terminals of each machining current source. And a second constant voltage power consuming body having a voltage lower than that of the first constant voltage power consuming body, the second constant voltage power consuming body being constituted by a series connection body of a constant voltage source.

In the power supply device of the electric discharge machine according to the present invention, when the number of connected machining current sources increases, the second constant voltage power consuming body consumes energy due to the wiring inductance when the power is cut off, and the number of connected machining current sources is increased. The power consumption of the first constant-voltage power consumer does not increase even if the power consumption increases.

In a power supply device for an electric discharge machine according to the next invention, the second constant voltage power consuming body is connected to a diode and a capacitor connected in proximity to a connection terminal and a position apart from an electrode of the capacitor. And a cooling body is attached to the constant voltage source.

In the power supply device for an electric discharge machine according to the present invention, the constant voltage source is installed at a position distant from the electrode of the capacitor, in other words, at a position connected to the connection terminal. Even if installed in the vicinity of the processing tank and the positioning device, they are not affected by heat generated by the constant voltage source, and the constant voltage source is cooled by the cooling body.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the embodiment of the present invention, the same components as those of the above-mentioned conventional example are designated by the same reference numerals as those of the above-described conventional example, and the description thereof will be omitted.

(Embodiment 1) FIG. 1 shows Embodiment 1 of a power supply device for an electric discharge machine according to the present invention.

Each of the processing current sources 40 _{1 to} 40 n is a constant voltage power consuming body (hereinafter referred to as a first constant voltage power consuming body) formed by a series connection body of a diode 114 and a constant voltage source 115.
It has a 116 ₁ ~116n.

A second constant voltage power consuming body 1 having a lower voltage than the first constant voltage power consuming bodies 40 _{1 to} 40 n is connected between the terminals of the intermediate connection points E and W. The second constant voltage power consuming body 1 is configured as a series connection body of a diode 2 and a constant voltage source 3.

2A to 2D show the first constant voltage power consuming bodies 40 _{1 to} 40 n and the second constant voltage power consuming bodies 40 _{1 to} 40 n when the power supply is cut off in the power supply device of the first embodiment shown in FIG. 2 shows the energy consumption per one time of the constant voltage power consumer 1.

2 (a), (b), (c), and (d) show the energy consumption by the constant voltage power consuming body when the number of parallel processing current sources is 1, 2, 4, and 8. In the figure, d3 is the energy consumption of the second constant voltage power consumer 3. The data of this consumed energy is that the output current of the machining current source 40 ₁ is 60 A and the output current of the machining current sources 40 _{2 to} 40 n is 80 A.
A, the machining current source 40 ₁ first constant voltage power bodies 116 ₁ ～116N constant voltage source 115 provided in the ~40n
Is 60 V, the voltage of the constant voltage source 3 of the second constant voltage power consuming body 1 is 25 V, the wiring inductances L _{10 to} Ln ₀ are 1.5 μH, the wiring inductance L ₁ is 0.5 μH, the electrode and the work piece. This is when the discharge voltage between them is 25V.

As can be seen from FIGS. 2 (a) to 2 (d), 25
When the second constant voltage power consuming body 1 of V is provided, energy is not consumed in the second constant voltage power consuming body 1 up to four units in parallel, and the first constant voltage power consuming bodies 116 _{1 to} 116 n are not consumed. The energy consumption is the same as when the second constant voltage power consumer 1 is not provided. This is because the voltage between the connection terminals E and W is 2
This is because it does not exceed 5V.

When eight units are connected in parallel, the energy consumption of the first constant voltage power consumer 116 ₁ of the machining current source 40 ₁ is 4.
5 mj, 40 _{2 to} 40 n of the first constant voltage power consumer 11
Energy consumption of 6 ₂ ~116n becomes 8.0mj. Further, the energy consumed by the second constant voltage power consumer 1 is 19.6 mj.

The configuration of the power supply device of this electric discharge machine is 5
The energy consumption of the constant voltage power consuming body 116 ₁ of the machining current source 40 ₁ is 4.5 mj, and the first constant voltage power consuming body 116 ₂ of the machining current sources 40 _{2 to} 40 n is for the number of parallel units or more.
The energy consumption of 116n is 8.0 mj, which is constant. When the number of parallel processing current sources increases, the energy consumed by the second constant voltage power consumer 1 increases.

Therefore, when designing the power supply device of the electric discharge machine, the machining current sources 40 ₁ to 40
If the maximum power consumption of the constant voltage power consuming bodies 116 _{1 to} 116 n of 40 n is determined, the processing current sources 40 _{1 to} 40 n may be the same as each other, and the first constant voltage power consuming body may be the same depending on the number of parallels. 116 ₁ does not need to change the maximum power of ～116N.

Further, here, the second constant voltage power consumer 1
The voltage of the constant voltage source 3 is set to 25V, but this voltage may be another voltage, and the lower the voltage, the smaller the number of parallel connections, and the second constant voltage power consuming body 1 starts to consume power. The greater the amount, the greater the energy absorbed.

For example, if this voltage is set to 10 V, energy is not consumed in the second constant voltage power consuming body 1 until the two units are connected in parallel, and the first constant voltage power consuming bodies 116 _{1 to} 116 n.
The energy consumption at is the same as the energy consumption when the constant voltage source 3 of the second constant voltage power consumer 1 is not provided.

When three or more units are connected in parallel, the machining current source 4
The energy consumption of the first constant voltage power consuming body 116 ₁ of 0 ₁ is 3.1 mj, and the energy consumption of the first constant voltage power consuming body 116 _{2 to} 116 n of the machining current sources 40 _{2 to} 40 n is 5.6 mj. . Further, the energy consumed by the second constant voltage power consumer 1 is 36.7 mj when 8 units are connected in parallel.
It is.

As described above, between the terminals of the connection points E and W,
In the power supply device of the electric discharge machine to which the second constant voltage power consuming body 1 is connected, it is necessary to change the maximum power of the first constant voltage power consuming bodies 116 _{1 to} 116 n according to the number of parallel constant voltage sources. Since they may be the same as each other, the price is low, and there is an effect that the design is easy when designing the power supply device of the electric discharge machine according to the current value.

Next, the operation in the special case of the first embodiment will be described. In FIG. 1, connecting points E and W are electrodes 12
0 and the workpiece Wr as close as possible, when the inductance L ₁ of the common wirings 42 and 43 has a value given by the following equation, the voltage between the connection points E and W when the machining current is off becomes zero. .

L ₁ = {(discharge voltage) × (inductance of output line)} / {(voltage of constant voltage source 115) × (number of parallels)} (Equation 1) In the state of this Equation 1, the connection point The voltage of the constant voltage source 3 of the second constant voltage power consumer 1 connected between the E and W terminals is set to zero, and only the diode 2 is connected. Therefore, the second constant voltage power consumer 1 consumes almost no power.
The energy of the inductance L ₁ of the common wirings 42 and 43 is absorbed between the electrode 120 and the workpiece Wr, and the energy of the inductances L _{10 to} Ln ₀ of the output lines 41 _{1 to} 41n is the respective processing current sources 40 _{1 to} 40n. All of them are consumed by the first constant voltage power consumers 116 _{1 to} 116 n.

The common wiring 4 which brings about the state of the expression 1
When the connection points E and W are set at the positions of the inductance L ₁ of 2 and 43, the first constant voltage power consumers 116 _{1 to} 116
The power consumption of n is constant regardless of the number of parallel processing current sources 40 _{1 to} 40 n. Further, the energy of the inductance L ₁ of the common wirings 42 and 43 is consumed as a part of the processing power, which also has the effect of improving the processing speed. Furthermore, the best thing is that the second constant voltage power consuming body 1 consumes almost no power, and since the diode 2 only has a simple configuration, it is small and lightweight and uses a large heat radiator. You don't have to have it, and you can get a low price.

However, a common condition that results in the condition of this expression 1
Inductance L of wiring 42, 43 ₁Connection point at
Setting E and W is too common wiring 42, 43
Inductance L₁Connection becomes poor as
Will be possible. In such a case, the common wirings 42 and 43
Inductance L₁Is slightly larger than the position where satisfies Expression 1.
Even if the connection points E and W are set at the threshold position, the machining current is cut off.
If the time is within the allowable range, the second constant voltage power consumption above
The voltage of the constant voltage source 3 of the body 1 is set to zero, and the diode 2 only
Can be connected.

Eight machining current sources are arranged in parallel, and the machining current source 40
₁Output current of 60A, machining current source 40_Two~ 40n output
Output current is 80A, first constant voltage power consumer 1
16 ₁The voltage of the constant voltage source 115 of ~ 116n is 60V,
The voltage of the constant voltage source 3 of the second constant voltage power consumer 1 is set to 0V.
And wiring inductance L_Ten~ L₈₀1.5 μH, discharge
When the voltage is set to 25V, from the connection points E and W according to Equation 1,
Wiring inductance L to the electrode 120 and the workpiece Wr₁
Is 0.078 μH, which is a small inductor
It is practically impossible to connect them.

If the connecting points E and W are provided at the position where L ₁ is 0.2 μH, the interruption time of the machining current is about 4.6 μs.
And the wiring inductance L _{1 of the} first embodiment is 0.
Performance almost equal to the condition set at 5 μH is obtained.

(Second Embodiment) FIG. 3 shows a second embodiment of a power supply device for an electric discharge machine according to the present invention.

In the second embodiment, the machining current sources 40 ₁ to 4
First constant-voltage power consuming bodies 116 _{1 to} 11 by a series connection body of a diode 114 and a constant-voltage source 115 at each 0n.
In addition to 6n is provided, the diode 2 and the output terminal 1 second constant voltage power body 1 ₁ 1n by series connection of the machining current source 40 ₁ ～40N of a constant voltage source 3
It is connected between 16 and 117. In this embodiment as well, the voltage of the second constant voltage power consuming bodies 11 1 to ₁ n is set to be lower than the voltage of the first constant voltage power consuming bodies 116 _{1 to} 116 n.

Since the voltage of the second constant voltage power consuming bodies 1 1 to ₁ n is set to be slightly lower than that of the first constant voltage power consuming bodies 116 _{1 to} 116 n, the inductances L _{10 to} Ln ₀ are set when the current is cut off. And the energy stored in L ₁ is consumed by the second constant voltage power consuming bodies 1 ₁ to ₁ n. When the number of parallel processing current sources increases, the first constant voltage power consumer 1
Since the power consumed by 16 _{1 to} 116 n is too large,
By connecting the second constant voltage power body 1 ₁ 1n with sufficient power capacity connected to the output terminal 116 and 117, can be used without changing the machining current source 40 ₁ ~40n. Therefore, there is an effect that the design is easy when designing the power supply device of the electric discharge machine having many parallels.

(Embodiment 3) FIG. 4 shows Embodiment 3 of the power supply device for an electric discharge machine according to the present invention.

In the third embodiment, the constant voltage power consumer 1
Is a diode 2 connected close to the connection terminals E and W,
It has a capacitor 130 and a constant voltage source 1 connected at a position away from the electrodes of the capacitor 130, and the constant voltage source 1 is attached to a cooling body 134. Constant voltage source 1
Is composed of a semiconductor (transistor) 131, a resistance element 133, and a Zener diode 132. As the semiconductor 131, a semiconductor having a current amplification function such as MOSFET, IGBT, or transistor can be used. The cooling body 134 is a forced air cooling type radiating fin that is cooled by sending air by the blower 135. The cooling body 135 can also be cooled by flowing water or oil.

The connection terminals E and W are the electrode 120 and the workpiece W.
Since it is installed as close as possible to r, it is installed near the processing tank and the positioning device. Therefore, if heat is generated in this portion, the processing accuracy may be deteriorated due to an increase in the temperature in the processing tank or an increase in the temperature of the electrode feed mechanism.

Therefore, only the diode 2 and the capacitor 130, which generate less heat, are installed near the connection terminals E and W, and the constant voltage source 3 is installed at a position where the processing accuracy is not affected even if the heat is generated a little away from the connection terminals E and W. The electrode and the constant voltage source 3 are connected by an electric wire with as little inductance as possible. As the electric wire with the smallest possible inductance, there is a twisted electric wire formed by twisting two electric wires, a coaxial cable, or the like. The energy of the inductance of the wiring in the OFF state accumulated in the capacitor 130 is promptly consumed by the semiconductor 131 of the constant voltage source 3 and cooled by the cooling body 134 by the electric wire having the least inductance.

The constant voltage power consuming body 1 according to the third embodiment is small in size and light weight suitable for being installed in the vicinity of a processing tank or a positioning device, and can consume a large amount of power at a slightly distant position. There is an effect that an electric discharge machine that allows a discharge current to flow can be obtained.

[0051]

As is apparent from the above description, in the power supply device of the electric discharge machine according to the present invention, since the voltage of the second constant voltage power consuming body is lower than that of the first constant voltage power consuming body, When the number of connected current sources increases, the second constant voltage power consumer consumes energy due to the wiring inductance when the power is cut off.Therefore, even if the number of connected current sources increases, the first constant voltage power consumer consumes energy. The power does not increase, and it is not necessary to change the maximum power of the first constant voltage power consumer according to the number of parallel connections. As a result, the first constant voltage power consuming bodies provided in each machining current source may be the same as each other, the cost is reduced due to the productivity, and the power supply device of the electric discharge machine having a large number of parallels corresponding to the current value is provided. The design becomes easy when designing.

Next, in the power supply device of the electric discharge machine according to the present invention, since the energy of the inductance of the common wiring is consumed as a part of the machining power, the effect of improving the machining speed can be obtained, and the second constant voltage can be obtained. Since the power consuming body consumes almost no power, this second constant voltage power consuming body can be a simple configuration with only a diode, is small and lightweight, and does not need to use a large cooler for heat dissipation. There is an effect that a low price can be done.

In the power supply device for an electric discharge machine according to the next invention, when the number of machining current sources connected is increased because the voltage of the second constant voltage power consuming body is lower than that of the first constant voltage power consuming body, the power source is increased. Since the second constant-voltage power consumer consumes energy due to the wiring inductance when shutting off, the power consumption of the first constant-voltage power consumer does not increase even if the number of connected machining current sources increases. It is not necessary to change the maximum power of the first constant voltage power consumer. As a result, the first constant-voltage power consumer provided in each machining current source may be the same as each other, the cost is reduced due to improved productivity, and the power supply device of the electric discharge machine has a large number of parallels according to the current value. Also when designing, the design becomes easy.

In the power supply device of the electric discharge machine according to the next invention, the constant voltage source of the second constant voltage power consumer is installed at a position apart from the electrode of the capacitor, in other words, at a position apart from the connection terminal. Therefore, even if the connection terminals are installed near the machining tank or the positioning device of the electric discharge machine, they are not affected by the heat generated by the constant voltage source and should be installed near the machining tank or the positioning device. It is suitable for small size, light weight, and has the effect of consuming a large amount of power at a position slightly distant from it, and since the constant voltage source is cooled by the cooling body, even if the energy consumption by the constant voltage source increases, the constant voltage source Source never overheats.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a power supply device for an electric discharge machine according to the present invention.

FIG. 2 is a graph showing an energy consumption level of a constant voltage source in the power supply device according to the first embodiment.

FIG. 3 is a circuit diagram showing a second embodiment of a power supply device for an electric discharge machine according to the present invention.

FIG. 4 is a circuit diagram showing a third embodiment of a power supply device for an electric discharge machine according to the present invention.

FIG. 5 is a circuit diagram showing an example of a conventional power supply device for an electric discharge machine.

FIG. 6 is a circuit diagram showing an example of a constant voltage source used in a power supply device for an electric discharge machine.

FIG. 7 is a circuit diagram showing another example of a conventional power supply device for an electric discharge machine.

FIG. 8 is a graph showing an energy consumption level of a constant voltage source in a conventional power supply device for an electric discharge machine.

[Explanation of symbols]

1, 1 _{1 to} 1n second constant voltage power consumer, 2 diode, 3 constant voltage source, 40, 40 _{1 to} 40n machining current source, 41 _{1 to} 41n output line, 42, 43 common wiring,
100 constant current supply unit, 101 gate drive circuit, 10
2 switching elements, 103 diodes, 105
Reactor, 110 output current interrupting means, 111 gate drive circuit, 112 switching element, 113 diode, 114 diode, 115 constant voltage source, 11
6,116 ₁ ～116N first constant voltage power bodies, 1
17,118 output terminal 120 electrode, 130 capacitor, 131 semiconductor, 132 Zener diode,
133 resistance element 134 cooling body, 135 blower, E, W intermediate connection point Wr work piece

Claims (4)

[Claims] 1. A power supply device of an electric discharge machine, wherein a plurality of machining current sources are connected by output lines at a common intermediate connection point, and the intermediate connection points are connected to an electrode and a workpiece by common wiring. A first constant voltage power consuming body by a series connection body of a diode and a constant voltage source provided in the processing current source, and provided between the terminals of the intermediate connection point, by a series connection body of the diode and the constant voltage source And a second constant voltage power consuming body having a voltage lower than that of the first constant voltage power consuming body, the power source device of the electric discharge machine. 2. The inductance L _{1 of the} common wiring is set to have a value represented by the following equation, the voltage of a constant voltage source of the second constant voltage power consuming body is set to zero, and only a diode is connected. The power supply device for an electric discharge machine according to claim 1, wherein: L ₁ = {(discharge voltage) × (output line inductance)}
/ {(Voltage of the constant voltage source of the first constant voltage power consumer) ×
(Number of parallels)} 3. A power supply device of an electric discharge machine, wherein a plurality of machining current sources are connected by output lines at a common intermediate connection point, and the intermediate connection points are connected to an electrode and a workpiece by common wiring. A first constant-voltage power consumer consisting of a diode and a constant-voltage source connected in series to the machining current source, and a series-connected body of a diode and a constant-voltage source provided between the output terminals of each machining current source. And a second constant voltage power consuming body having a voltage lower than that of the first constant voltage power consuming body, and a power supply device for an electric discharge machine. 4. The second constant voltage power consumer has a diode and a capacitor connected in proximity to a connection terminal, and a constant voltage source connected in a position apart from an electrode of the capacitor, The power supply device for an electric discharge machine according to claim 1, wherein a cooling body is attached to the constant voltage source.