JP3926463B2 - Burnout prevention device for electrical equipment that determines the rated output by period - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a burnout prevention device for an electric device that determines a rated output by a period, such as a power supply device for welding.
[0002]
[Prior art]
For example, in a power supply apparatus for welding, a rated current value L and a rated usage rate α are determined in order to prevent burning of device parts due to overload, and the rated usage rate α is for a period of 10 minutes. That is, in the case of a power supply device having a rated current value L of 350 A and a rated usage rate α of 60%, the total time that can be welded at a current value of 350 A in any 10 minutes is 6 minutes, and the remaining 4 minutes are used. must not. Therefore, when welding is to be performed at the current value I, the operator obtains the allowable usage rate β of the current value I by Equation 1, and performs the work so that the welding time in an arbitrary 10 minutes does not exceed the allowable usage rate β. I was going.
β = (L / I) ² × α …… Equation 1
Therefore, when welding is performed at a current value of 300 A using the power supply device described above, the allowable usage rate β is calculated by calculation to be 81%, and if welding is performed for 8 minutes, 2 minutes are rested.
[0003]
[Problems to be solved by the invention]
However, the management performed by the workers is voluntary and is not always performed. Moreover, even when the allowable usage rate is exceeded, the power supply device does not burn out immediately. For this reason, it may be used by overload, and the lifetime of the power supply device was shortened.
[0004]
The object of the present invention is to solve the above-mentioned problems in the prior art, prevent the operator from using the electric device beyond the rated time without managing the usage time, and extend the life of the electric device. An object of the present invention is to provide a burnout prevention device for an electric device that determines the rated output that can be produced by the period.
[0005]
[Means for Solving the Problems]
To achieve the above object, the present onset bright from the setter of the rated current value, a setter rated utilization, and duration of the setter, and a current detector, an arithmetic unit, a storage unit, a timer It becomes square and said output stop when it exceeds the product of the rated utilization and period of the rated current in a shorter period than a set period of time by the square of the sum the setter of the detected current value you output a signal, a burning prevention device of the electric device for determining the nominal output in the period, depending on the magnitude of the sum of squares of current values in advance determined period until the time of outputting the output stop signal output it characterized in that it defines the suspension period.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments.
FIG. 1 is an external connection diagram in the case where a burnout prevention device for an electric device for determining a rated output according to an embodiment of the present invention is applied to a power supply device for welding. In the figure, 1 is a power supply device for a consumable electrode type DC arc, the rated current value L is 350 A, the rated usage rate α is 60%, and the period K is 10 minutes. Reference numeral 2 denotes a fan that cools the inside of the power supply device 1. Reference numerals 3 and 4 denote external output terminals. Reference numeral 5 denotes a positive output cable that connects the external output terminal 3 and the wire 6. A torch switch 7 is placed on the torch 8. 9 is a welding load and 10 is a base material. Reference numeral 11 denotes a negative output cable which connects the external output terminal 4 and the base material 10. Reference numerals 12 and 13 denote torch switch cables, which are connected to a control unit (not shown) of the power supply device 1 through a switch 28.
[0008]
Reference numeral 20 is a burnout prevention device, 21 is a setter for the rated current value L, 22 is a setter for the rated usage rate α, and 23 is a setter for the period K, each connected to the storage device 24. An arithmetic unit 25 is connected to the storage device 24. A timer 26 is connected to the storage device 24, the arithmetic device 25, and the integrator 27. The integrator 27 integrates the voltage output from the shunt 30 and outputs the integrated value M to the arithmetic unit 25 every unit time Δt (here, 0.5 seconds). Reference numeral 28 denotes a double switch. One switch is connected to the torch switch cables 12 and 13 on the a contact side, and the other switch is connected to the alarm lamp 29 on the b contact side. A shunt 30 is arranged between the external output terminal 3 and the output cable 5 and outputs a voltage corresponding to the current flowing inside.
[0009]
Next, the operation of the present embodiment will be described.
FIG. 2 is a flowchart showing a control procedure. The rated current value L, the rated usage rate α, and the period K of the power supply device 1 are set in advance by the setting devices 21 to 23 and stored in the storage device 24 (step S100 in FIG. 2). Here, L = 350, α = 60, and K = 10 are input. When a setting completion button (not shown) is turned on, the switch 28 is turned on, and the arithmetic unit 25 determines the allowable amount Q (where Q = L ² × α × K) and the order corresponding to the heat generation amount allowed in the period K. The maximum value imax of i (here, imax = 1200 since the unit time Δt is 0.5 seconds) is calculated (step S110). Next, the order i of i is set to i = 0, and Z _{1 to} Z ₁₂₀₀ to be described later are all set to 0 (step S120), and the output of the integral value M is awaited (step S130). When the switch 28 is turned on, the torch switch 7 can be operated.
[0010]
When the integrated value M is output from the integrator 27, an average voltage in unit time Δt is obtained and converted into an average current value I, and unit calorific value Z (where Z = I ² × Δt, where Z = 0.5). × I ² ) is obtained (procedure S140). Then, 1 is added to the order i (procedure S150), and it is confirmed whether i> 1200 (procedure S160). When i ≦ 1200, immediately after i = 1200, i = 1 is set (procedure S160). S170), Z _i = Z (procedure S180). Next, the sum ΣZ of unit calorific values Z _{1 to} Z ₁₂₀₀ and the allowable amount Q are compared (step S190). If ΣZ ≦ Q, the process of step S130 is performed. If ΣZ> Q, the process of step S300 is performed. Do.
[0011]
In procedure 300, switch 28 is turned off. Then, the alarm lamp 29 is turned on and the torch switch 7 becomes inoperable. Next, the total calorific value B ₆ for 6 consecutive minutes immediately before this point (sum of unit calorific values Z _i from i = i−721 to i = i. 720 is 6 minutes × 60 seconds / min ÷ 0. This is the value obtained at 5 seconds / time. The same applies hereinafter) and is compared with 0.95Q (step S310). When B ₆ > 0.95Q, the pause time T is set to 4 minutes ( Step S320) and step S330 are performed. If B ₆ ≦ 0.95Q, the total amount of heat B ₇ for 7 minutes immediately before this point is calculated and compared with 0.95Q (step S340). If B ₇ > 0.95Q, The pause time T is set to 3 minutes (step S350), and the process of step S330 is performed.
[0012]
If B ₇ ≦ 0.95Q, the total amount of heat B ₈ for 8 consecutive minutes immediately before this point is calculated and compared with 0.95Q (step S360). If B ₈ > 0.95Q, The pause time T is set to 2 minutes (step S370), and the process of step S330 is performed. If B ₈ ≦ 0.95Q, the total amount of heat B ₉ for 9 minutes immediately before this point is calculated and compared with 0.95Q (step S380). If B ₉ > 0.95Q, The pause time T is set to 1 minute (procedure S390), and if B ₉ ≦ 0.95Q, the pause time T is set to 0.5 minutes (procedure S400), and the process of procedure S330 is performed.
[0013]
In step S330, the switch 28 is turned on again after waiting for the time t after the switch 28 is turned off to pass the pause time T (step S410), and the process of step S120 is performed.
[0014]
In the case in the procedure S310 i <720, the sum of Z ₁ to Z _i and _{Z 1200-i + 1 ~Z 1200} . Similarly, in the case of step S340, step S360, and step S380, the total sum of the continuous unit heat generation amounts Z _i immediately before the stop is calculated.
[0015]
In the above, when the total heat quantity ΣZ becomes equal to the allowable quantity Q, the downtime is determined in accordance with the immediately previous total heat quantity, so no useless downtime occurs and the rating of the electric device is almost 100%. Can be used.
[0016]
In the above, the rated current value L, the rated usage rate α, and the period K can be set. For example, the power supply device 1 is operated with a rated current value of 500 A, a rated usage rate of 60%, and a period of 10 minutes. In this case, the rated current value is 350 A, the rated usage rate is 70%, the period is 10 minutes, that is, the torch 8 having a rating lower than that of the power supply device 1 is connected and welding is performed at a welding current of 300 A. However, if the rated current value L, the rated usage rate α, and the period K are set in accordance with the rating of the torch 8, the torch 8 can be prevented from being burned without exceeding the rating of the torch 8.
[0017]
In the description of the above embodiment, the unit time Δt is 0.5 seconds, but it may be further shortened or lengthened.
[0018]
Further, the suspension period may be a fixed length.
[0019]
Further, a buzzer may be used instead of the warning lamp 29, or a pause period may be displayed.
[0020]
Further, the burnout prevention device 20 may be incorporated in the welding power source 1. In this case, the set values of the rated current value L, the rated usage rate α, and the period K may be fixed.
[0021]
【The invention's effect】
As described above, according to the present invention , the operator can be prevented from using beyond the rating of the electric device without managing the usage time, and the life of the electric device can be extended . The rest period can be set to an appropriate length.
[Brief description of the drawings]
FIG. 1 is an external connection diagram when a burnout preventing apparatus according to an embodiment of the present invention is applied to a welding power supply apparatus.
FIG. 2 is a flowchart showing a control procedure according to the embodiment of the present invention.
[Explanation of symbols]
5 Output cable 7 Torch switch 21, 22, 23 Setting device 25 Computing device 30 Shunt

Claims (1)

It consists of a setter for the rated current value, a setter for the rated usage rate, a setter for the period, a current detector, an arithmetic unit, a storage device, and a timer. in the square and the you output the output stop signal when it exceeds the product of the rated utilization and duration, the period the rated output of the rated current in a shorter period than the period set by the setting device An electrical device burnout prevention device ,
An apparatus for preventing burnout of an electrical apparatus for determining a rated output by a period, wherein the output stop period is determined according to a sum of squares of current values in a predetermined period until the output stop signal is output .

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