TWI595246B - Sheathed heater and load testing device - Google Patents

Description

Sheath heater and load tester

The present invention relates to a sheath heater and a load test device including the sheath heater.

As shown in the patent document 1 of the prior art, there is a sheath heater for a load test device or the like.

Patent Document 1: Japanese Patent Laid-Open Publication No. 2010-25752

The heater terminal of the sheathed heater generally includes a male threaded portion and is generally formed in a cylindrical shape. Therefore, if the torsion force of the nut is too strong, the male thread portion may be rotated, and the heater may be caused. The connection state between the terminal and the resistance wire is broken.

Accordingly, an object of the present invention is to provide a sheath heater or the like which is easy to maintain a state in which a heater terminal and a resistance wire are connected.

The sheathed heater of the present invention includes a cylindrical portion, a resistance wire disposed inside the cylindrical portion, and a heater terminal connected to both ends of the resistance wire; and the heater terminal has a function for screwing with the nut a first end portion having a male screw shape and partially exposing a portion from the cylindrical portion, and a second end portion having a cylindrical shape and a part of the electric resistance wire wound; and a side surface of the end portion before the first end portion The exposed portion of the cylindrical portion is provided with at least one of: a hole portion or a concave portion extending in a direction parallel to a radial direction of the first end portion; or a flat portion perpendicular to a radial direction .

The tool is held by a tool such as a pliers or a wrench to contact the front end portion of the first end portion at least in contact with the flat portion. After the tool is held, the holding tool can exhibit the effect of preventing rotation by the nut. When the screwing is performed, even if the nut is excessively rotated, the heater terminal is difficult to rotate, and the disconnection of the resistance wire and the heater terminal can be prevented (it is easier to maintain the connection state between the heater terminal and the resistance wire).

Further, since the heater terminal is in a state in which it is difficult to rotate, another advantage is that it is easy for the user to recognize whether or not the nut is over-rotated.

Further, when the rod is inserted into the hole portion (in the concave portion), after the rod is held, the rod held can exhibit the effect of preventing the rotation, and even if there is a nut rotation when the nut is screwed by the nut In the excessive situation, the heater terminal is difficult to rotate, and the disconnection of the resistance wire and the heater terminal can be prevented (it is easier to maintain the connection state of the heater terminal and the resistance wire).

More preferably, in the front end portion of the first terminal, a cylindrical portion is provided, and the cylindrical portion has a path length smaller than or equal to a valley diameter of a male thread constituting a male thread shape portion: and in the cylindrical portion The front end is provided with a flat portion.

The flat portion is not pulled by the nut, but the nut can be smoothly screwed.

Further, in a preferred embodiment, two or more planar portions having a parallel positional relationship are provided in a portion exposed from the cylindrical portion on the side surface of the end portion before the first end portion.

More preferably, in the front end portion of the first terminal, a cylindrical portion is provided, and the cylindrical portion has a path length smaller than or equal to a valley diameter of a male thread constituting a male thread shape portion: and in the cylindrical portion The front end is provided with a hole or a recess.

The hole or recess is not pulled by the nut, but the nut can be smoothly screwed.

Further, more preferably, the insulating powder is further filled in the inside of the cylindrical portion, and the heater terminal has a first end portion, a second end portion, and an intermediate portion between the first end portion and the second end portion; The first end portion, the intermediate portion, and the second end portion are integrally formed, and the intermediate portion includes at least one of a portion having a shape other than a circular cross section, or a position of a center of gravity of the cross-sectional shape deviates from the first end portion And the extension of the central axis of the second end.

In the intermediate portion of the heater terminal, a portion having a shape different from that of the cylindrical shape is provided. Therefore, the insulating powder filled in the vicinity of the position can function to prevent rotation, and even if it is screwed by a nut, When the nut is rotated excessively, the heater terminal is difficult to rotate, and the disconnection of the resistance wire and the heater terminal can be prevented (it is easier to maintain the connection state between the heater terminal and the resistance wire).

Further, since the heater terminal is in a state in which it is difficult to rotate, another advantage is that it is easy for the user to recognize whether or not the nut is over-rotated.

More preferably, the intermediate portion includes a portion whose cross-section exhibits a shape other than a circle, and the cross-section exhibits a portion other than a circular shape, and is a polygonal column shape, from the center of gravity of the cross-section of the polygonal shape to The total length of the line segment forming the outer shape of the cross-sectional shape of the polygonal shape is longer than the radius of the circle forming the cross section of the second end portion.

More preferably, for a column having the same cross-sectional shape as the cross-sectional shape of the polygonal column shape and having a height higher than that of the polygonal column shape, the portion corresponding to the first end portion and the second end portion is cut to form a heater. Terminal.

Further, in a preferred embodiment, the intermediate portion includes a portion having a shape in which the cross section has a circular shape, and the intermediate portion has a cylindrical portion having a diameter larger than that of the first end portion and the second end portion, and the cross section has a shape other than a circular shape. The portion is formed by cutting or deforming a portion of the cylindrical portion.

More preferably, the cross section is a portion of a shape other than a circle, and a polygonal column shape is exhibited.

Further, in a more preferable manner, the cross-section is a portion having a shape other than a circular shape, and a portion in which a part of the circular shape portion is crushed is exhibited.

Further, in a preferred embodiment, the intermediate portion includes a portion of the center of gravity of the cross-sectional shape that is offset from the extension of the central axis of the first end portion and the second end portion; and the intermediate portion has a larger diameter than the first end portion and the second portion. The cylindrical portion of the end portion is formed by bending a part of the cylindrical portion away from the extension line of the central axis of the first end portion and the second end portion.

Further, in a preferred embodiment, the cylindrical portion holds the first end portion of the heater terminal via the first insulating member embedded in the opening portion, and the insulating powder covers all of the first end portion and the second end portion. And all of the intermediate portions are filled, and the insulating powder is opposed to the first insulating member, and a gap filling operation is performed.

The load test device of the present invention includes a plurality of sheathed heaters including a cylindrical portion, a resistance wire disposed inside the cylindrical portion, and a heater terminal connected to both ends of the resistance wire; and a plurality of sheath heating The device is used for dry load testing, and the heater terminal has a first end portion which is in the shape of a male screw and partially exposed from the cylindrical portion; and a second end portion which is cylindrical and is wound around a part of the electric resistance wire a portion of the end portion of the end portion before the first end portion exposed from the cylindrical portion, at least one of the following: a hole portion or a recess portion extending in a direction parallel to a radial direction of the first end portion; Or, a plane portion perpendicular to a radial direction.

Further, more preferably, the insulating powder is further filled in the inside of the cylindrical portion, and the heater terminal has a first end portion, a second end portion, and an intermediate portion between the first end portion and the second end portion; The first end portion, the intermediate portion, and the second end portion are integrally formed, and the intermediate portion includes at least one of a portion having a shape other than a circular cross section, or a position of a center of gravity of the cross-sectional shape deviates from the first end portion And the extension of the central axis of the second end.

As described above, according to the present invention, it is possible to provide a sheath heater or the like which is easy to maintain the connection state between the heater terminal and the electric resistance wire.

1‧‧‧Load test device

10‧‧‧Front frame

11‧‧‧ Cover

20‧‧‧Resistor

21‧‧‧ 台台

30‧‧‧ Cooling Department

40‧‧‧Connection Switching Department

41‧‧‧Operation Department

41a‧‧‧ mode switch

41b‧‧‧Resistance switch

43‧‧‧Terminal connection

61‧‧‧resistance line

62‧‧‧Interstitials

63‧‧‧heater terminal

63a‧‧‧1st end

63a1‧‧‧Cylinder

63a2‧‧‧Flat Department

63a3‧‧‧ hole or recess

63b‧‧‧2nd end

63c‧‧‧Intermediate

63c1‧‧‧ roughly cylindrical part

63c2‧‧‧A section of a cross-section that is shaped like a circle

63c3‧‧‧The position of the center of gravity of the cross-sectional shape is separated from the extension of the central axis of the first end

64‧‧‧Insulating powder

65a, 65b‧‧‧1st insulating member, 2nd insulating member

66‧‧‧ nuts

67‧‧‧Cylinder

68‧‧‧ bushing

69‧‧‧heating fan

G1~G12‧‧‧1st resistor group~12th resistor group

R‧‧‧Resistors (sheath heaters)

SB‧‧‧ Shorting bar

Fig. 1 is a front view of the load test apparatus of the embodiment.

Fig. 2 is a side view of the load test apparatus of the embodiment.

Fig. 3 is a view showing the configuration of a load tester in the embodiment.

Fig. 4 is a view showing a side surface of one of the resistor portions.

Fig. 5 is a view showing the other side of the resistor portion.

Figure 6 is a perspective view of the vicinity of the terminal of the resistor.

Fig. 7 is a cross-sectional structural view showing a positional relationship between a resistor including a heater terminal and a gantry, wherein the heater terminal has an intermediate portion formed in a corner column shape.

Fig. 8 is a perspective view of a heater terminal having an intermediate portion which is formed in a prismatic shape in a part of a cylindrical portion.

Fig. 9 is a perspective view of a heater terminal having an intermediate portion which deforms a portion of the cylindrical portion by being crushed.

Fig. 10 is a perspective view of a heater terminal having an intermediate portion including a corner post shape formed by a cutting method.

Figure 11 is a perspective view of a heater terminal having an intermediate portion that is partially bent.

Fig. 12 is a cross-sectional structural view showing a positional relationship between a resistor including a heater terminal and a gantry, wherein the heater terminal has an intermediate portion formed only of a cylinder.

Figure 13 is a perspective view of a heater terminal having an intermediate portion which is formed only of a cylinder.

Figure 14 is a cross-sectional structural view of the resistor in the filling step.

Fig. 15 is a cross-sectional structural view of the resistor after the step of reducing the diameter.

Figure 16 is a cross-sectional structural view of the resistor after the heating step.

Fig. 17 is a cross-sectional structural view of the resistor after the embedding step.

Fig. 18 is a cross-sectional structural view of the resistor after the screwing step.

Fig. 19 is a cross-sectional structural view showing a positional relationship between a resistor including a heater terminal and a gantry, wherein the heater terminal has a first end portion and is provided with a cylindrical portion including a flat portion.

Fig. 20 is a perspective view of a heater terminal having a first end portion and a cylindrical portion including a flat portion.

Fig. 21 is a perspective view showing a first terminal of a cylindrical portion including a flat portion and a middle portion of the heater terminal;

Fig. 22 is a perspective view showing a first terminal of a cylindrical portion including a hole portion and a middle portion of the heater terminal;

Hereinafter, the present embodiment will be described using the drawings. The dry load test apparatus 1 of the present embodiment includes an outer frame 10, a resistor unit 20, a cooling unit 30, and a connection switching unit 40 (see FIGS. 1 to 11 and FIGS. 14 to 22).

Further, in order to explain the directivity, the horizontal direction in which the connection switching portion 40 and the outer frame 10 are arranged side by side is referred to as the x direction, the horizontal direction perpendicular to the x direction is referred to as the y direction, and the vertical direction perpendicular to the x direction and the y direction is taken as the vertical direction. The z direction is explained.

The outer frame 10 houses the resistor portion 20 in the upper stage and the cooling unit 30 in the lower stage. Further, a connection switching portion 40 is provided in a side portion of the outer frame 10, and a caster is provided at a lower portion.

On the side of the outer frame 10 (the surface of the heater terminal 63 constituting the resistor R of the resistor portion 20), a cable or a shorting bar for protecting the heater terminal 63, connected to the heater terminal 63, and the like are provided. The cover 11 of the gantry 21 of the resistor R is held (see Fig. 2).

The cover 11 is made of a conductive material such as iron or aluminum.

The resistor portion 20 is configured by arranging a plurality of resistor rows in a rod-shaped resistor R parallel to the y direction so as to be spaced apart from each other at a predetermined interval in the x direction, and forming a plurality of parallel rows in the z direction. It is used to perform load test on the test object power source such as the connected generator through the terminal connection portion 43. The resistor R receives the power supply from the test object power source.

In the resistor R of the present embodiment, there are nine resistor rows arranged side by side in the x direction, and 13 segments are arranged side by side in the z direction. However, the number of resistors R arranged side by side in each resistor row or the number of segments in which the resistor columns are overlapped is not limited thereto.

Furthermore, the resistor R of at least one resistor column (in the example of FIGS. 4 and 5, the uppermost resistor row) is used as a replacement for other resistor R failures; The resistor R of the other resistor row is preferably used as the resistor R constituting the first resistor group G1 to the 12th resistor group G12.

The resistor R constituting the resistor portion 20 is a resistor group R of six or twelve resistors as a resistor group, and changes the voltage applied from the power source of the test object by changing the number of resistor groups. For load testing.

Further, the connection in the resistor group (the connection state of the resistor R in the resistor group) is changed in accordance with the type of the power source of the load test object.

The resistor unit 20 has a first resistor group G1 to a 12th resistor group G12. In the present embodiment, the resistor R having a rated voltage of 400 V and a rated capacity of 167 W is referred to as a first resistor group G1 (rated capacity: 1 kW) of 6 in total; and a rated voltage of 116 V is rated capacity: 334 W. The resistor R is a total of six second resistor groups G2 (rated capacity: 2 kW, the third resistor group G3 is also the same); the rated voltage: 116V rated capacity: 834W resistor R is a total of six The fourth resistor group G4 (rated capacity: 5 kW); the rated voltage: 116V rated capacity: 1.67 kW resistor R as a total of six fifth resistor group G5 (rated capacity: 10 kW, sixth resistor group) G6 is the same); the rated voltage: 116V rated capacity: 1.67kW resistor R as the 7th resistor group G7 (rated capacity: 20kW, 8th resistor group G8 ~ 12th resistor group) G12 is also the same) as an example of the setting. However, the number of resistor groups G, or their respective rated voltages or even rated capacities, is not limited to the above configuration.

The resistor (sheath heater) R has a coil-shaped resistor wire 61 such as a nichrome wire, and a heater terminal (button) 63 electrically connected to the resistor wire 61 at both ends of the resistor wire 61; The first insulating member 65a holds the heater terminal 63 and covers the cylindrical portion of the side surface of the electric resistance wire 61 or the heater terminal 63 (which is a portion that is not exposed to the outside from the wall constituting the gantry 21) ( Heater tube 67) (refer to Figs. 6 to 8).

Further, FIG. 7 or a cross-sectional structural view of FIG. 12 and FIG. 14 to FIG. 19 which will be described later is a cross section of the member other than the electric resistance wire 61, the heater terminal 63, and the nut 66, and the electric resistance wire 61 and the heater terminal 63 and The nut 66 is shown on the side.

A heat releasing fan 69 is provided on the side surface of the cylindrical portion 67.

The heater terminal 63 has a first end portion 63a having a male screw shape for screwing with the nut 66 and a portion exposed from the cylindrical portion 67, and a second end portion 63b which has a substantially cylindrical shape and a part of the electric resistance wire 61 is wound around the intermediate portion 63c of the first end portion 63a and the second end portion 63b; the first end portion 63a, the intermediate portion 63c, and the second end portion 63b are integrally formed Composition.

The first end portion 63a may be formed only by a male screw shape portion. However, a portion in which the end portion of the male screw portion is exposed from the cylindrical portion 67 may be further provided. The cylindrical portion 63a1 having a diameter smaller than or equal to the valley diameter of the male thread, and a side portion 63a2 perpendicular to a radial direction is provided on the side of the front end of the cylindrical portion 63a1 by cutting or the like (FIG. 19 to FIG. 21); or, on the side surface of the front end of the cylindrical portion 63a1, a hole portion (or recess portion) 63a3 extending in a direction parallel to one radial direction is provided (see FIG. 22).

By the tool such as a pliers or a wrench, the end portion of the first end portion 63a is sandwiched at least in contact with the flat portion 63a2, and after holding the tool, the holding tool can exert the effect of preventing rotation, by When the nut 66 is screwed, even if the nut 66 is excessively rotated, the heater terminal 63 is difficult to rotate, and the disconnection of the resistance wire 61 and the heater terminal 63 can be prevented (it is easier to maintain the heater terminal 63 and the resistor). The connection state of the line 61).

Therefore, in a preferred embodiment, one or more of the two planar portions 63a2 belonging to the parallel positional relationship are provided so as to be surely held by the figure. In the example of Fig. 21, one set of two flat portions 63a2 in a parallel positional relationship is provided.

Further, when the rod is inserted into the hole portion (in the concave portion) 63a3, the rod which is held can maintain the effect of preventing the rotation after the rod is held, and even if there is a screw when screwed by the nut 66 When the cap 66 is excessively rotated, the heater terminal 63 is hard to rotate, and the disconnection of the electric resistance wire 61 and the heater terminal 63 can be prevented (it is easier to maintain the connection state of the heater terminal 63 and the electric resistance wire 61).

Further, since the heater terminal 63 is in a state in which it is difficult to rotate, another advantage is that it is easy for the user to recognize whether or not the nut 66 is over-rotated.

Further, in the form adopted, at least one of the flat portion 63a2 and the hole portion (or the recess portion) 63a3 may be provided in a portion of the end side surface of the male screw-shaped portion from the cylindrical portion 67, however, in order to make the flat portion The flange 63a3 or the hole portion 63a3 can be smoothly screwed by the nut 66. Preferably, the nut portion 63a1 is provided with a cylindrical portion 63a1 having a diameter smaller than or equal to the valley diameter of the male thread, and then in the cylindrical portion. 63a1 is provided with at least one of the flat portion 63a2 and the hole portion (or recess portion) 63a3.

The intermediate portion 63c has a central axis identical to the central axis LX of the first end portion 63a and the second end portion 63b, and includes a substantially cylindrical portion 63c1 having a diameter larger than that of the first end portion 63a and the second end portion 63b, and The cross section shows a portion 63c2 of a shape other than a circle.

For example, a column (cylindrical shape) having a circular cross section is cut into portions corresponding to the first end portion 63a and the second end portion 63b, so that the state of the heater terminal 63 formed is not yet formed in the intermediate portion. The cross section of 63c exhibits a portion 63c2 of a shape other than a circle, and (as will be described later) a state in which the position of the center of gravity of the cross-sectional shape is away from the portion 63c3 of the extension line of the central axis LX.

The cross-sectional shape of the portion 63c2 having a circular shape other than that of the circular shape can be formed into a substantially polygonal column shape formed by cutting or press working on a part of the intermediate portion 63c as shown in Figs. 7 and 8 As shown in Fig. 9, a part of the intermediate portion 63c is subjected to press working or the like as shown in Fig. 9, and is formed by a crushed shape (a cross section having a substantially elliptical shape or the like).

In this case, the shape other than the circular shape is formed from the center of gravity of the shape other than the circular shape to the side of the shape or the arc forming the shape, so that the line length is at least slightly shorter than forming a substantially cylindrical shape. The radius of the circle of the cross section of portion 63c1.

Further, the shape other than the circular shape may be formed such that the shape other than the circular shape is polygonal, and the center of gravity of the polygonal shape is longer than the side of the outer shape forming the outer shape, and the second end is formed. The radius of the circle of the cross section of the portion 63b and the substantially cylindrical portion 63c1 is long (refer to Fig. 10).

In this case, for the columnar (polygonal column) having a polygonal cross section, the entire heater terminal 63 can be formed by cutting, including the substantially cylindrical portion 63c1 located above and below, and the shape of the cross section being circular. Part 63c2).

Specifically, the cross section is the same as the cross section of the polygonal column shape, and the column shape has a longer height (the height of the first end portion 63a, the second end portion 63b, and the intermediate portion 63c). The shape is cut to correspond to the first cylindrical portion 63a, the second end portion 63b, and the substantially cylindrical portion 63c1 of the intermediate portion 63c to form the heater terminal 63.

For example, if the member of the regular hexagonal column is cut to be equivalent to the substantially cylindrical portion 63c1 of the first end portion 63a, the second end portion 63b, and the intermediate portion 63c, the heater terminal 63 can be obtained, and its cross section. A portion 63c2 having a shape other than a circle has a regular hexagonal column shape.

Further, the intermediate portion 63c may be formed by bending a part of the substantially cylindrical portion 63c1 or the like to replace (or superimpose) the portion 63c2 having a circular shape other than the circular cross section. Further, the formed form includes a portion 63c3 (see FIG. 11) in which the position of the center of gravity of the cross-sectional shape is shifted from the extension line of the central axis LX of the first end portion 63a and the second end portion 63b.

A part of the electric resistance wire 61 is wound around the second end portion 63b, and is fixed by spot welding or the like.

The inside of the cylindrical portion 67 is filled with an insulating powder 64 such as magnesium oxide, and is fixed by compression and heating.

The insulating powder 64 is filled so as to cover a part of the first end portion 63a, all of the second end portion 63b, and the entire intermediate portion 63c.

The portion of the insulating powder 64 that faces the first insulating member 65a (the boundary portion between the insulating powder 64 and the first insulating member 65a) and the portion of the male screw portion of the first end portion 63a are applied by silicone or the like. Interstitial 62.

By the gap filler 62, a part of the male screw shape portion of the first end portion 63a and the insulating powder 64 are fixed.

The nut 66 is screwed to the first end portion 63a in a state in which the first insulating member 65a and the cylindrical portion 67 are sandwiched therebetween.

If the intermediate portion 63c of the heater terminal 63 is not provided with a shape different from a substantially cylindrical shape such as a corner post shape (see FIGS. 12 and 13), if the nut 66 is screwed, if it is excessively rotated, The cap 66 may cause the heater terminal 63 to slide and rotate, and may damage the connection state of the electric resistance wire 61 and the heater terminal 63.

In the present embodiment, the intermediate portion 63c of the heater terminal 63 is provided with a portion 63c2 having a shape other than a circular cross section such as a polygonal column shape, or a cross-sectional shape thereof is provided to shift the position of the center of gravity from the first end portion 63a. And a portion 63c3 of the extension line of the central axis LX of the second end portion 63b, that is, a portion having a shape different from a substantially circular shape, so that the insulating powder 64 filled in the vicinity of the position can exhibit an effect of preventing rotation. When the nut 66 is screwed, even if the nut 66 is excessively rotated, the heater terminal 63 is difficult to rotate, and the disconnection of the electric resistance wire 61 and the heater terminal 63 can be prevented (it is easier to maintain the heater terminal). 63 is connected to the resistance wire 61).

Further, since the heater terminal 63 is in a state in which it is difficult to rotate, another advantage is that it is easy for the user to recognize whether or not the nut 66 is over-rotated.

Further, a part of a substantially cylindrical shape of the intermediate portion 63c of the heater terminal 63 is cut or deformed by cutting or press working, and can be easily formed into a substantially circular shape. Become part of a different shape.

Further, in the case of the cutting process, the stress is not concentrated at a position of the intermediate portion 63c of the heater terminal 63 as compared with the press working or the bending process, so that the formed heater terminal 63 can be included There is a portion 63c2 having a cross-sectional shape that is a shape other than a circle.

The manufacturing sequence of the resistor R will be described later.

The heater terminal 63 of the resistor R is connected to the heater terminal 63 of the other resistor R by a SB shorting bar, or is connected to the terminal connecting portion 43 or the relay by a cable.

The resistor R is covered on the side surface by a truss 21 composed of four walls.

The position of the resistor R that is not electrically connected to the heater terminal 63 (near the both ends of the cylindrical portion 67 of the heater terminal 63 via the first insulating member 65a) is separated by the second insulating member 65b. The wall constituting the gantry 21 is held.

As shown in Fig. 6, the end portions of the four resistors R held by the gantry 21 are two of them (the ones are not provided with the cylindrical portion 63a1 including the flat portion 63a2 at the first end portion 63a). The heater terminals 63 are connected to each other by the SB shorting bars.

Further, the gantry 21 is opened to the upper surface and the lower surface so that the cold air blown by the cooling unit 30 provided at the lower portion can flow toward the upper portion.

In order to effectively perform the cooling performed by the cooling unit 30, the resistors R of the resistor rows are arranged such that the resistor R constituting the resistor row and the resistor R adjacent to the resistor R in the x direction In the intermediate position, a resistor R of a resistor column adjacent in the Z direction is disposed.

In the lower portion of the resistor portion 20 (the lower portion of the outer frame 10), a cooling portion 30 having a cooling fan is provided.

A relay provided in the cooling unit 30 or the resistor unit 20 for controlling each resistor group of the power supply from the test object power source toward any resistor group, and other power sources different from the test object power source (load test) The device is driven by a power source (see Fig. 3).

The connection switching unit 40 has an operation unit 41 and a terminal connection unit 43 (see FIGS. 2 and 3). The terminal connection portion 43 may be disposed at a position apart from the operation portion 41 (for example, on the back surface of the operation portion 41 or the like).

The operation unit 41 has a mode changeover switch 41a and a resistance changeover switch 41b.

The mode changeover switch 41a is a rotary dial type operation switch for on/off of the load test device 1, and for selecting the power source type (mode switching) of the test object.

The resistance switch 41b is a slide type (or toggle type or push button type) operation switch for controlling the on/off of each of the relays of the first resistor group G1 to the 12th resistor group G12.

When the first operation switch S1 is turned on, the relay of the first resistor group G1 is turned on (on state), and the current of the test target power source connected to the load test device 1 can be transmitted through the terminal. The connection portion 43 flows to the first resistor group G1.

The second operation switch S2 to the twelfth operation switch S12 are also the same, and after the on state is reached, the relay corresponding to the resistor group is turned on (on state). In its state, the current of the test object power source connected to the load test device 1 can be transmitted to the resistor group through the terminal connection portion 43.

When the rotational position of the mode changeover switch 41a is aligned with the rotational position (operation mode) corresponding to the type of the test target power source, the cooling fan of the cooling unit 30 is driven, and the switch is switched according to the resistance. In the operation state of 41b, the on/off control of each of the relays of the first resistor group G1 to the 12th resistor group G12 is performed.

Further, in the form of the main power switch, the main power switch may be turned on, and the rotational position of the mode switch 41a may be aligned with the type of the power source of the test object (operation mode). When the cooling fan is driven or the on/off control of each of the first resistor group G1 to the 12th resistor group G12 is performed.

The terminal connection portion 43 is a terminal for connecting the power source of the test object, and the terminal connection portion 43 allows the test target power source to be connected to the first resistor group G1 to the twelfth resistor group G12.

Next, the manufacturing procedure of the resistor R will be described (see FIGS. 14 to 18).

The cylindrical portion 67 is inserted into an object in which the electric resistance wire 61 is attached between the two heater terminals 63, and is held such that the opening of the cylindrical portion 67 faces the vertical direction, and the opening at the lower side is gel-like. In a state in which the bushing 68 is plugged, the insulating powder 64 is introduced into the inside of the cylindrical portion 67 so as to cover all of the first end portion 63a, the second end portion 63b, and all of the intermediate portion 63c (see Figure 14 is a filling step).

At this time, in order to fill a large amount of the insulating powder 64 without a gap, it is preferable to provide vibration to the cylindrical portion 67 or the like, and to inject the sufficiently dried insulating powder 64 in this state.

After the filling of the insulating powder 64 is completed, the upper side of the cylindrical portion 67 is closed by the rubber-like bushing 68, and the side surface of the cylindrical portion 67 is subjected to the reduction processing to be compressed (refer to the figure). 15 steps to reduce the diameter).

The cylindrical portion 67 is heated in a state where the upper and lower bushes 68 are removed (refer to the heating step of Fig. 16).

The insulating powder 64 is solidified by the reduction step and the heating step to form a sintered body.

In the exposed portion of the insulating powder 64 near the opening of the cylindrical portion 67 (portion opposed to the bushing 68), the caulk 62 is applied by silicone or the like, and then the first insulating member 65a is embedded ( Refer to the embedding step of FIG. 17). Further, a heat releasing fan 69 is attached to the cylindrical portion 67.

The nut 66 is screwed to the first end portion 63a, and the first insulating member 65a and the cylindrical portion 67 are sandwiched between the nuts 66 to complete the resistor R (see the screwing step of Fig. 18).

When the first end portion 63a is provided with the flat portion 63a2, the front end portion of the first end portion 63a is sandwiched by at least one portion of the flat portion 63a2 by a tool such as a pliers or a wrench. The screwing is performed while the tool is held.

When the first end portion 63a is provided with a hole portion (or a recess portion) 63a3, a rod is inserted into the hole portion (or the recess portion) 63a3, and the rod is held in a state where the rod is held. Hehe.

In the description of the present embodiment, the heater terminal 63 is provided with a resistor R (sheath heater) having a portion different from the substantially cylindrical shape in a part of the intermediate portion 63c, and is used for the heater terminal 63. The dry load test device 1, however, the use of the sheath heater is not limited to the dry load test device, and may be used for other purposes such as an electric heater.

R Resistor 21 Rack 61 Resistance wire 62 Interstitial 63 Heater terminal 63a First end portion 63b Second end portion 63c Intermediate portion 64 Insulating powder 65a, 65b First insulating member, second insulating member 66 Nut 67 Cylinder Department 69 heat release fan

Claims (9)

A sheathed heater comprising: a cylindrical portion; a resistance wire disposed inside the cylindrical portion; a heater terminal connected to both ends of the resistance wire; and an insulating powder filled in the cylindrical portion The heater terminal has a first end portion and is formed in a male thread shape for screwing with the nut, and a portion is exposed from the cylindrical portion; the second end portion has a cylindrical shape and is wound a part of the electric resistance wire; and an intermediate portion sandwiched between the first end portion and the second end portion; the first end portion, the intermediate portion, and the second end portion are integrally formed; The portion includes at least one of: a first portion having a shape other than a circular cross section; and a second portion having a center of gravity of a cross-sectional shape offset from a central axis of the first end portion and the second end portion An extension portion; the intermediate portion having a cylindrical portion having a diameter larger than the first end portion and the second end portion; and in the case where the intermediate portion includes the first portion, the first portion is to the cylindrical portion a part of which is formed by cutting or deforming; in the middle part When the second portion of the containing case, the second bent portion in a part of the line of the cylindrical portion is formed. The sheathed heater according to claim 1, wherein at least one of the side portions of the end portion before the first end portion is exposed from the cylindrical portion: toward the first end a hole or recess extending in a direction parallel to the radial direction; and a flat portion perpendicular to the one radial direction. A sheathed heater according to claim 2, wherein a cylindrical portion is provided at an end portion of the first end portion, and the diameter of the cylindrical portion is less than or equal to a valley of a male thread constituting the male thread shaped portion. a diameter; the flat portion is provided at a front end of the cylindrical portion. The sheathed heater according to the second aspect of the invention, wherein the portion of the end portion of the end portion that is exposed from the cylindrical portion is provided with one or more of the two parallel plane positions. unit. A sheathed heater according to claim 2, wherein a cylindrical portion is provided at an end portion of the first end portion, and the diameter of the cylindrical portion is less than or equal to a valley of a male thread constituting the male thread shaped portion. a hole; a hole or a recess is provided at a front end of the cylindrical portion. The sheathed heater of claim 1, wherein the intermediate portion comprises the first portion; the first portion is in the shape of a polygonal column; from the center of gravity of the cross-section of the polygonal column shape to formation The total length of the line segment up to the outer side of the cross section of the polygonal column shape is longer than the radius of the circle forming the cross section of the second end portion. The sheathed heater according to the first aspect of the invention, wherein the cylindrical portion holds the first end portion of the heater terminal via a first insulating member that is fitted into the opening; the insulating powder is filled Covering a part of the first end portion, all of the second end portion, and all of the intermediate portion; and filling the gap with the first insulating member in the insulating powder . A load testing device comprising a plurality of sheathed heaters, the sheathed heater comprising: a cylindrical portion, a resistance wire disposed inside the cylindrical portion, and two ends connected to the resistance wire a heater terminal; the plurality of sheathed heaters are used as resistors for dry load testing; the heater terminals have a first end portion, a male thread shape, and a portion is exposed from the cylindrical portion; the second end a portion having a cylindrical shape and wound around a portion of the electric resistance wire; and an intermediate portion sandwiched between the first end portion and the second end portion; the first end portion, the intermediate portion, and the second portion The end portion is integrally formed; the intermediate portion includes at least one of: a first portion having a shape other than a circular cross section; and a second portion having a center of gravity of a cross-sectional shape offset from the first end portion And an extension line of the central axis of the second end portion; the intermediate portion has a cylindrical portion having a diameter larger than the first end portion and the second end portion; and when the intermediate portion includes the first portion, the Part 1 is to apply a part of the cylindrical portion to the cutting So as to form the deformed; at the intermediate portion comprises a portion of the case 2, the second line portion is bent in a part of the cylindrical portion is formed. The load test apparatus according to claim 8, wherein at least one of the portions of the end side surface exposed from the cylindrical portion before the first end portion is provided toward the first end portion a hole or recess extending in a direction parallel to the radial direction; and a flat portion perpendicular to the one of the radial directions.