JP4724838B2 - Current control resistor element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a current control resistor element used for controlling a heating element such as an electric furnace.
[0002]
[Background Art and Problems to be Solved by the Invention]
Conventionally, when a voltage of 100 to 400 volts is applied to a heating element for generating a temperature of 0.01 ohm or less, a power regulator using a semiconductor is often destroyed by an initial excessive current, and a transformer In many cases, the heating element is heated at a voltage of 100 volts or less by using the voltage and the resistance value of the heating element is increased, and then a prescribed voltage is applied.
[0003]
In addition, the voltage adjustment method starting from 0 volts with the slidac is large in accordance with the high power, has the disadvantage that it does not fit inside the electric furnace, etc., and the automatic adjustment device for adjusting the heat generation temperature is large, so always There is a disadvantage of manual adjustment.
[0004]
In addition, a resistor can be used to prevent an initial excessive current. However, the electric power used by the heating element is 10 kilowatts or more, and a small electric furnace has a large resistor. There is a drawback, and in an electric furnace where the heat generating temperature of the heating element is 1500 ° C. or higher, the resistor is melted because there are many nichrome wires when it is put together inside the electric furnace, so it is not usually used.
[0005]
Moreover, although a semiconductor rectifier element for large current can be used for current limiting, the internal resistance value of the semiconductor does not gradually change to a low resistance value, and thermal destruction occurs due to an increase in self-temperature. There is a disadvantage that it takes necessary expenses.
[0006]
The present invention solves the above-mentioned conventional drawbacks, and prevents the destruction of the semiconductor power regulator due to the initial excessive current of the heating element having a low resistance value, and directly connects the heating element to the desired voltage without using a transformer. It is an object of the present invention to provide a current control resistance element that can be controlled to a high level.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a current control resistor element according to claim 1 of the present invention has a volume ratio of 90% inside a cylindrical holder made of an alumina silicon oxide ceramic material that is electrically insulating and can withstand high temperatures. 10% to 10% tellurium material powder and 10% to 90% volume ratio carbon material powder are mixed, and this mixed powder is pressed and compressed into an arbitrary shape to form a synthetic resistance element, An external connection terminal made of a metal material connected to both ends of the composite resistance element is fixed to both ends of the holder .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 5 show an embodiment of a current control resistor element according to the present invention. FIG. 1 is a perspective view of a composite resistor element, FIG. 2 is a plan view of the current control resistor element, and FIG. FIG. 4 is a diagram for explaining the electrical characteristics of the current control resistor element, and FIG. 5 is an electrical circuit diagram showing an application example of the current control resistor element.
[0009]
In FIG. 1, the composite resistance element 1 constituting the current control resistance element of the present invention is for mixing powder of tellurium material and carbon material to obtain an arbitrary high resistance value or low resistance value in an arbitrary shape. In addition, a powder of tellurium having a volume ratio of 90% to 10% is mixed with a powder of carbon material having a volume ratio of 10% to 90%, and the mixed powder is press-compressed into an arbitrary shape. . In the embodiment of FIG. 1, the composite resistance element 1 is formed in a cylindrical shape, but may be any shape such as a prismatic shape or an elliptical column shape.
[0010]
In another embodiment, a powder of an arbitrary metal material can be mixed with a powder of tellurium material to reduce a large current and a change time of the resistance value with a low resistance value. As the metal material, powders such as copper, nickel, and aluminum are used. When mixing metal materials, tellurium powder of 80% to 20% by weight and metal powder of 20% to 80% by weight in order to obtain an arbitrary resistance value and resistance change time. The body is mixed and pressed into an arbitrary shape and molded.
[0011]
FIG. 2 shows a current control resistance element A. The above-described composite resistance element 1 is disposed inside a holder 2 made of a cylindrical ceramic material, and both ends 1A of the composite resistance element 1 are made of a metal material. The external connection terminal 3 is connected, and the external connection terminal 3 is fixed to both end portions 2 </ b> A of the holder 2. The ceramic material of the holder 2 is an electrically insulating material and uses an alumina silicon oxide system that can withstand high temperatures. The external connection terminal 3 is provided with a connection screw terminal 3A for connection to an electric circuit.
[0012]
As shown in FIG. 3, when a heating element (resistance) R and an AC power source are connected to the connecting screw terminals 3A at both ends of the current control resistance element A, the current control resistance element A has the electrical characteristics shown in FIG. Therefore, due to the current flowing in the circuit, the resistance value of the internal resistance of the current control resistor element A gradually decreases due to self-heating. Therefore, a gradually increasing current flows through the heating element R. In this case, the current control resistive element A generates heat in proportion to the flowing current, but the resistance value of the tellurium material itself decreases, so that the resistance may become red hot like other linear resistors. No. In addition, since the tellurium material itself generates heat quickly, it does not reach a high temperature like other linear resistors even under the same power condition.
[0013]
FIG. 5 shows an application example in which the current control resistive element A of the present invention is connected between the SCR semiconductor power regulator 4 of a three-phase circuit and three heating elements R. The resistance value of the voltage adjusting resistor 5 connected to the SCR semiconductor power regulator 4 is adjusted to adjust the summer temperature applied to the heating element R. However, the heating element R is forgotten to adjust the voltage adjusting resistor 5. Even when a high voltage is applied to the SCR, since the current control resistor element A is connected to the circuit, the SCR semiconductor power regulator 4 can be prevented from being broken.
[0014]
Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications are possible. For example, in the above embodiment, the current control resistance element and the heating element are connected to the AC circuit, but may be connected to the DC circuit.
[0015]
【The invention's effect】
As is apparent from the above description, according to the present invention, it is possible to vary the small current to the large current, the change time of the resistance value, etc. in any shape regardless of the voltage, and no heat dissipation device is required, and the heat resistance is 450 ° C. Can be used up to self-temperature to the extent. And the destruction of the semiconductor power regulator due to the initial excessive current of the low resistance heating element can be prevented, and the heating element can be directly controlled to the desired voltage without using a transformer.
FIG. 1 to FIG. 5 show an embodiment of a current control resistor element of the present invention, and FIG. 1 is a perspective view of a composite resistor element.
FIG. 2 is a plan view of a current control resistor element.
FIG. 3 is an electric circuit diagram of a current control resistor element.
FIG. 4 is a diagram for explaining electrical characteristics of a current control resistor element.
FIG. 5 is an electric circuit diagram showing an application example of a current control resistor element.
[Explanation of symbols]
1 ... Composite resistance element 2 ... Holder 3 ... External connection terminal

Claims (1)

  Inside a cylindrical holder made of an alumina silicon oxide ceramic material that is electrically insulating and can withstand high temperatures, a tellurium material powder with a volume ratio of 90% to 10% and a carbon material with a volume ratio of 10% to 90% A composite resistance element formed by mixing powder and press-compressing the mixed powder into an arbitrary shape is disposed, and external connection terminals made of a metal material connected to both ends of the composite resistance element are arranged at both ends of the holder. A current control resistor element characterized by being fixed to a portion.

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