JPH05200545A - Power source for arc machining - Google Patents

Abstract

PURPOSE:To reduce the size and weight of a power source and to improve reliability by supplying a driving current directly from an input power source only when the voltage of a high level is received to operate a cooling fan in the power source for arc machining receives selectively two kinds of voltages of a high level and a level and can set and control the output according to the voltage level. CONSTITUTION:At the time of receiving AC 100V/200V selectively, the cooling fan 15 with the rated input voltage as AC 200V is connected directly to input side wiring from the input power source 1, the cooling fan 15 is operated normally only when 200V having the high maximum output of the power source and having a high inside calorific value is inputted and the cooling fan 15 is not operated or rotated at a low speed when 100V having the low maximum output of the power source and having the 1 inside calorific value is inputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an AC 100V / 200
It is possible to selectively receive two types of input power supply voltage, such as a high level and a low level such as V, and to set and control the output according to the level of the received voltage. The maximum output depends on the level of each voltage. However, the present invention relates to a power source for arc machining such as welding and cutting, which produces a larger output when receiving a high level voltage.

[0002]

2. Description of the Related Art A conventional example of this type of arc machining power source is shown in FIGS. This conventional example is 1
FIG. 3 is a block diagram thereof, and FIG. 4 is a partial detailed view of FIG. 3, showing a power source for TIG welding which also serves as an input for 00V / 200V.
In FIGS. 3 and 4, the input power source 1 is a commercial frequency 100
It is either a V or a 200 V single-phase AC power supply, and each input power supply voltage is converted to DC by the input side rectifier circuit 2. Numerals 3 and 3'are contacts for switching circuit connection according to a switching command from a 100V / 200V discrimination circuit 11, which will be described later, and 3 is a main circuit and 3'is an auxiliary circuit. The switching contact 3 causes the input-side rectifier circuit 2 to act as a full-wave rectifier to charge the capacitor 4 when the input voltage is 200 V, and the voltage of 100 V is applied.
At the time of input, the input side rectifier circuit 2 acts as a voltage doubler rectifier to charge the capacitor 4. As a result, capacitor 4
The charging voltage of is the same voltage when inputting 100V and when inputting 200V. On the other hand, as shown in FIG. 4, the switching contact 3'is
At the time of 200V input, the primary winding 20 of the auxiliary transformer 13 '
Connect 0V terminal a and common terminal c to the input power supply 1,
At the time of V input, the 100V terminal b and the common terminal c of the primary winding of the auxiliary transformer 13 'are connected to the input power supply 1. as a result,
The voltage generated in the secondary winding of the auxiliary transformer 13 'is 100V
The voltage is the same when inputting and when inputting 200V. This secondary voltage of the auxiliary transformer is supplied to a later-described inverter control circuit 14 and the like as a control power supply voltage. 5 is an inverter,
Welding transformer 6 by converting the DC voltage of capacitor 4 into AC of a frequency higher than the commercial frequency (for example, 20 kHz)
Applied to the primary side of. An output side rectifier circuit 7 rectifies the AC voltage stepped down by the welding transformer 6 and outputs it as a DC voltage. A current detector 8 in the output circuit outputs a feedback signal for current control. Reference numeral 9 is an output current smoothing reactor, and 10 is a welding torch. Reference numeral 11 is a circuit for discriminating whether the received input power source voltage is 100 V or 200 V, and outputs a switching command to the switching contacts 3, 3'and 3 "according to the discrimination result. 12 and 12 'correspond to the level of the received voltage. 12 is an output current setting circuit for inputting 100V, and 12 'is 200V.
An output current setting circuit at the time of input, each set value is switched by a switching contact 3 ″. Reference numeral 14 is an inverter control circuit, and an output current value detected by a current detector 8 is output by the output current setting circuits 12, 12 ′. The output pulse width of the inverter 5 is controlled so as to match the set value, and 15 'is a cooling fan for forced air cooling in order to suppress the temperature rise of the heating elements inside the power supply within the temperature rise limit of each heating element. In this conventional example, as shown in FIG. 4, a cooling fan 15 'having a rated input voltage of 100 V AC is connected to the 100 V terminal b and the common terminal c of the primary winding of the auxiliary transformer 13' to directly input at 100 V input. Drive current of the cooling fan is supplied from the input power source 1 and 200V
At the time of input, by supplying the drive current of the cooling fan through the primary winding of the auxiliary transformer 13 ', at the time of 100V input, 2
The cooling fan 15 'is operated normally when the input voltage is 00V.

[0003]

In the above conventional example, the cooling fan 15 'having a rated input voltage of AC 100V is connected to the auxiliary transformer 1.
Since it is connected to the 100V terminal b and the common terminal c of the primary winding 3 ', the auxiliary transformer 13' when the input voltage is 200V
A driving current for the cooling fan flows through the primary winding. Therefore, it is necessary to make the wire of the primary winding thick, and the auxiliary transformer 13 '
There was a problem that the rated capacity (VA), the volume and the weight of the product became large.

Even if a cooling fan having a rated input voltage of AC200V is connected to the 200V terminal a and the common terminal c of the auxiliary transformer 13 ', the auxiliary transformer 13' will be operated at 100V input.
The drive current of the cooling fan flows through the primary winding of the motor, causing the same problem as described above.

Further, when the cooling fan is operated even at the time of inputting 100 V as in the above-mentioned conventional example, there is a problem that the amount of dust accumulated inside the power source increases due to the intake of the outside air, and the insulation deterioration of the circuit parts is likely to occur.

According to the present invention, in this type of arc machining power source, when a low level voltage is received, the maximum output is limited by the input capacity, and the amount of heat generated inside the power source is small, so there is no need for forced air cooling. Based on the premise, the cooling fan is operated only when a high level voltage is received, and the driving current of the cooling fan is directly supplied from the input power source at that time to solve the above problem.

[0007]

To achieve the above object, the present invention selects a rated input voltage of a cooling fan in accordance with a high level input power supply voltage, and only when a high level voltage is received, the cooling fan is selected. Is normally operated, and when a low level voltage is received, the cooling fan is not operated or is rotated at a low speed, and the cooling fan is connected to the input side wiring for receiving the input power supply voltage.

[0008]

For example, in a power source for arc machining which is also used for inputting 100V / 200V, a cooling fan having a rated input voltage of AC 200V is directly connected to the input side wiring,
At the time of V input, the cooling fan receives a drive current from the input power source to operate normally, and the air is forcibly cooled so that the temperature rise of the heating elements inside the power source is suppressed within the temperature rise limit of each heating element. On the other hand, when 100 V is input, only 100 V is applied to the cooling fan for AC 200 V, so the cooling fan does not work or rotates at a low speed even if it works, but at this time, the maximum output of the power supply is limited and the internal power is limited. The amount of heat generated is small, and the temperature rise of the heating element inside the power supply does not exceed the temperature rise limit. It goes without saying that the drive current for the cooling fan does not flow through the auxiliary transformer.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram of an embodiment of the present invention intended for a 100 V / 200 V input type TIG welding power source, and FIG. 2 is a partial detailed view of FIG. In FIGS. 1 and 2, the same reference numerals as those in FIGS. 3 and 4 indicate corresponding parts, and the configuration and function of each part other than the auxiliary transformer 13 and the cooling fan 15 are the same as those of the conventional example shown in FIGS. It is the same.

With the 100 V / 200 V input type TIG welding current, the maximum input current is 100 V input.
The maximum output current is limited to 5A. In this embodiment, the maximum output current at the time of 100 V input is about 60 A, and the internal heat generation amount of the welding power source at this time is about 250 W.
Is. On the other hand, the maximum output current at 200V input is 150
The internal heating value of the welding power source at this time is about 1 kW or more. The cooling fan 15 is for suppressing the temperature rise of the heating elements due to the internal heat generation within the temperature rise limit of each heating element, and originally, the thermal design is made so as to correspond to the maximum output at the time of 200V input. So 100
The forced air cooling by the cooling fan 15 is not required at the time of V input. Under such a premise, in the present embodiment, the cooling fan 15 having a rated input voltage of 200 V AC is directly connected to the input side wiring between the input power source 1 and the input side rectifying circuit 2. With this arrangement, the cooling fan 15 operates normally by receiving the drive current from the input power source 1 only when the input voltage is 200V.
At the time of inputting 0V, the cooling fan 15 does not operate because only the voltage of 100V is applied to the rated input voltage of 200V. Also, depending on the type of cooling fan, there are some that rotate at a low speed when inputting 100 V, but there is no problem.

In the conventional example shown in FIGS. 3 and 4, since the drive current of the cooling fan flows through the primary winding of the auxiliary transformer 13 ', it is necessary to make the wire of the primary winding thick, and the auxiliary transformer 13' is required.
The rated capacity (VA), volume, and weight of the
According to this embodiment, since the cooling fan drive current does not flow in the primary winding of the auxiliary transformer 13, the auxiliary transformer 13 may be dedicated to the control power supply, and can be made compact and lightweight.

In this embodiment, the input power supply voltage is applied to the cooling fan 15 even when inputting 100 V, but 100 V / 20
It is also possible to positively stop the operation of the cooling fan 15 by turning off the input of the cooling fan 15 at the time of 100V input by a relay or the like that operates according to the determination output of the 0V determination circuit 11.

In this embodiment, the case where the AC input cooling fan is used has been described. However, even when the DC input cooling fan is used, the DC voltage applied when a high level input power supply voltage is received is applied. The object of the present invention can be achieved by operating the cooling fan normally as the rated input voltage of the cooling fan and not operating the cooling fan when receiving a low level input power supply voltage.

The present invention is not limited to the TIG welding power source, but can be applied to other welding power sources (for example, clothing arc welding power sources) and cutting power sources. In addition, the present invention is 1
Not only 00V / 200V input, but 200V / 400V
It is also applicable when receiving input, etc.

[0016]

According to the present invention, the power source for arc machining is capable of selectively receiving two types of input power source voltage, a high level and a low level, and setting and controlling the output according to the level of the received voltage. In the above, since the drive current of the cooling fan can be directly supplied from the input power supply without passing through the auxiliary transformer, it has the effect of reducing the size and weight of the auxiliary transformer and reducing the price. It can also contribute to the reduction in size and weight.

Furthermore, when a low level voltage is received, the cooling fan is not operated or is rotated at a low speed, so that the life of the motor of the cooling fan is extended and the amount of dust accumulated inside the power supply due to the intake of outside air is reduced. Also, the insulation deterioration of the circuit parts is less likely to occur, and the reliability of the power supply is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a partial detailed view of FIG.

FIG. 3 is a block diagram of a conventional example.

FIG. 4 is a partial detailed view of FIG.

[Explanation of symbols]

1 ... Input power supply, 3, 3 ', 3 "... Circuit connection switching contact, 5
… Inverter, 6… Welding transformer, 11… 100V / 2
00V discrimination circuit, 12, 12 '... Output current setting circuit, 1
3 ... Auxiliary transformer, 14 ... Inverter control circuit, 15 ... Cooling fan.

Claims (1)

[Claims] 1. A high level and a low level of two types of input power supply voltage are selectively received, and the output can be set and controlled according to the level of the received voltage, and the maximum can be set according to each voltage level. In an arc machining power supply that outputs different power when it receives a high level voltage with different output, forced air cooling is used to keep the temperature rise of the heating elements inside the power supply within the temperature rise limit of each heating element. Select the rated input voltage of the fan according to the high level input power supply voltage, operate the cooling fan normally only when receiving a high level voltage, and do not operate the cooling fan when receiving a low level voltage, Or to rotate at low speed,
A power supply for arc processing, characterized in that a cooling fan is connected to the input side wiring that receives the input power supply voltage.