JP3375440B2 - Brushless synchronous motor discharge resistor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge resistor of a brushless synchronous motor.

[0002]

2. Description of the Related Art Among brushless synchronous motors, there is a discharge resistor connected in parallel with a field winding on the load side of a rectifier attached to a rotor. In this brushless synchronous motor, the AC voltage induced in the field winding during starting is controlled by the discharge resistance.

In a discharge resistor of a brushless synchronous motor (hereinafter, simply referred to as a discharge resistor) incorporated in such a brushless synchronous motor, conventionally, a resistance piece formed of an aluminum plate in an annular shape is overlapped, and this discharge is performed. The resistor is inserted and fixed in the rotor shaft.

Further, in this discharge resistor, in order to dissipate the heat generated in each resistance piece, a predetermined gap is formed between the resistance pieces, and the cooling air flowing through this gap forms
Cooling each resistor strip.

[0005]

However, in the conventional discharge resistor configured as described above, in the case of a brushless synchronous motor having a small capacity, it is necessary to obtain a space for accommodating the discharge resistor. , The outer frame of the brushless synchronous motor must be enlarged.

If the discharge resistor should be replaced by operating the brushless synchronous motor for a long period of time,
Loosen the bolts that secure the brushless synchronous motor to the installation surface, remove the coupling at the end of the rotor shaft that connects the load, and lift one side of the rotor shaft using a jack, etc. The bearing on one side of the rotor shaft must be removed. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a discharge resistor for a brushless synchronous motor that prevents the brushless motor from increasing in outer shape and can be easily replaced.

[0007]

According to a first aspect of the present invention, there is provided a discharge resistor for a brushless synchronous motor, wherein a plurality of resistor pieces are connected in series and are connected in series with each other via a first insulating plate. And a pair of mounting legs, one side of which is overlapped on the outside of the resistance piece via a second insulating plate and the other side of which is fixed to the rotating shaft of the brushless synchronous motor, and one side of the mounting leg and the first and second sides.
It is characterized in that the second insulating plate and the resistance piece are provided so as to penetrate through one side of the mounting leg and the first and second insulating plates and a fastener for tightening the resistance piece. The discharge resistor of the brushless synchronous motor according to the second aspect of the present invention is characterized in that the first insulating plate, the second insulating plate, and the resistance piece are strip-shaped.

[0008]

When the discharge resistor is attached to or removed from the rotating shaft of the brushless synchronous motor, it is fixed by the bolt inserted into the mounting leg so that the bearing inserted in the end of the rotor shaft can be fixed. There is no need to remove it.

Further, by forming the first and second insulating plates and the resistance piece in the shape of a strip plate, the mounting space occupying the outer circumference of the rotor shaft can be minimized, and the increase in the inertia of the rotor can be minimized. You can limit it to the limit.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a discharge resistor for a brushless synchronous motor according to the present invention will be described below with reference to the drawings. Figure 1
The top view which shows an example of the discharge resistor of the brushless synchronous motor of this invention, FIG. 2 is a right view of FIG.

In FIGS. 1 and 2, a pair of mounting holes 4a are symmetrically formed on one side of a pair of holding plates 4 bent into an L shape, and the other side of these holding plates 4 opposes each other. The strip-shaped interlayer insulating plates 3 are inserted into the respective surfaces.
The interlayer insulating plate 3 is formed by molding powdery mica into a smooth plate shape with a binder, and a pair of through holes through which an insulating pipe 6 described later is formed are symmetrically formed in the central portion. There is.

Inside the interlayer insulating plate 3, a resistor made of a strip-shaped resistor material having substantially the same shape as the interlayer insulating plate 3 and having a width narrower and longer than the interlayer insulating plate 3. The piece 1A is symmetrically inserted with the right side further protruding from the right end of the interlayer insulating plate 3 to the right side. These resistor pieces 1A
A pair of through holes, through which an insulating cylinder 6 described below is provided, are also formed in the central portion of the same at the same intervals as the through holes formed in the interlayer insulating plate 3, and a conductor connection is made at the right end of these resistor pieces 1A. There are holes.

Inside these resistance pieces 1A, small connection pieces 2 made of the same material as the interlayer resistance piece 1A and having the same plate thickness are inserted in the upper and lower left ends in FIG. 1 as shown in FIG. . On the right side of these connecting pieces 2 in FIG. 1, an interlayer insulating plate 3A having substantially the same shape as the interlayer insulating plate 3 but a slightly shorter length is formed.
Is inserted adjacent to the connecting piece 2 at the left end, and a pair of through holes into which an insulating tube 6 described later is inserted are also formed in the central portion of the interlayer insulating plate 3A.

Further inside the interlayer insulating plate 3A,
A resistance piece 1B having the same width as the resistance piece 1A and the same length as the pressing plate 4 is inserted with the left end thereof flush with the resistance piece 1A. A pair of through-holes, through which an insulating cylinder 6 described below is provided, are also formed in the center of these resistance pieces 1B, and the left ends of these resistance pieces 1B are connected to the outside of the resistance piece 1B by a connecting piece 2 And is welded to the left end of the resistance piece 1A.

Inside the resistor pieces 1B, the same connecting piece 2 as the connecting piece 2 described above is inserted at the right end, and on the left side of these connecting pieces 2 the same product as the interlayer insulating plate 3A described above. 3A is inserted adjacent to the left end of the connecting piece 2.

Further, a resistance piece 1B, which is the same product as the resistance piece 1B described above, is inserted inside these interlayer insulating plates 3A with the left end thereof flush with the left end of the resistance piece 1A described above. The left end of the resistance piece 1B is welded to the left ends of the pair of connecting pieces 2 and the resistance piece 1A which are adjacent to the outside of the resistance piece 1B.

Inside the resistor pieces 1B, a pair of connection pieces 2 are inserted at the right ends, and on the left side of these connection pieces 2, an interlayer insulating plate 3A is inserted adjacent to the left ends of the connection pieces 2. ing. The left ends of the resistance pieces 1B adjacent to the outside of the interlayer insulating plate 3A are welded to each other via the connection piece 2.

As a result, the resistance pieces 1A on both sides are connected in series via the connection piece 2 with the four resistance pieces 1B stacked via the interlayer insulating plate 3A inserted between the resistance pieces 1A. Has been done. 1 and 2, the resistance piece 1B is
Although it is shown with four sheets, this is omitted for simplification of description, and in actuality, as described above, there are cases where the number of sheets reaches 20, for example.

The resistance pieces 1A and 1B and the interlayer insulating plates 3 and 3A have insulating tubes 6 inserted into through holes formed in the resistance pieces 1A and 1B and the interlayer insulating plates 3 and 3A. The screw stud 5 is loosely fitted to the screw 6, the insulating washer 8 is loosely fitted to both ends of the screw stud 5, and washers and nuts are used for tightening.

A compression terminal is connected to a connection hole (not shown) formed at the right end of each resistor piece 1A, and an electric wire connected to a rectifier (not shown) is connected to this compression terminal. Mounting holes 4a for fixing the discharge resistor to the rotary shaft of the brushless synchronous motor with bolts are formed on both sides of the holding plate 4 of the discharge resistor.

In the discharge resistor constructed as described above, when fixed to the rotary shaft of the brushless synchronous motor via the holding plate 4, two or four units are provided in order to prevent imbalance of the moment of the rotary shaft. Are symmetrically attached to the outer circumference of the rotating shaft. In this case, a strip folding washer is inserted in the lower neck of the head of the bolt that is inserted into the mounting hole 4a of the holding plate 4 and fastened to the rotor shaft, and after tightening the bolt,
One side of the strip folding washer is on the head of the bolt, and the other side is the holding plate 4
By bending the end surface of the bolt, it is possible to prevent the bolt from loosening during long-term operation.

In the discharge resistor thus constructed, the number of the resistance pieces 1B and the number of the interlayer insulating plates 3A are changed so that the discharge resistances having different capacities can be attached to the brushless synchronous motors having different specifications. However, it can be easily dealt with.

Further, each interlayer insulating plate 3A and resistor piece 1B are
Since the shapes are the same and can be shared, it is possible to mass-produce at the same time as each interlayer insulating plate 3A and resistor piece 1B incorporated in the discharge resistor applied to the brushless synchronous motor of different specifications, and the manufacturing is easy. Becomes

When the brushless synchronous motor is operated for a long period of time and the resistance piece is oxidized and the resistance value is changed for replacement, the armature core is fixed by removing the protective cover without removing the bearing. Since it is possible to perform the removal and the mounting work from between the outer frames, the maintenance becomes easy.

Further, since the interlayer insulating plates 3 and 3A inserted between the holding plates 4 are mica materials, when the maximum allowable temperature of insulation according to the standard of electrical engineering and electrical industry, JEC-147 is C type. Can also be applied to.

Further, by interposing an interlayer insulating plate 3A made of mica material between the resistance pieces 1A, 1B, the resistance pieces 1A,
Since the gap between 1B can be minimized, the outer shape of the discharge resistor can be downsized. Moreover, since the height from the lower end of the pressing plate 4 can be suppressed by stacking the strip-shaped resistor pieces 1A and 1B and the interlayer insulating plates 3 and 3A, it is possible to reduce It is also possible to minimize the increase in rotor inertia.

In the above embodiment, an insulating tube and a double screw stud are used to tighten the resistance piece and the interlayer insulating plate. However, an insulating layer made of mica is formed on the outer periphery of the central portion of the double screw stud. Insulated studs may be used.

[0028]

As described above, according to the present invention, a plurality of resistor pieces that are stacked via the first insulating plate and are connected in series on one side, and a second insulating plate is provided outside the resistor pieces. A pair of mounting legs, one side of which is superimposed on the other side and the other side of which is fixed to the rotating shaft of the brushless synchronous motor;
By installing the one side of the mounting leg penetrating the second insulating plate and the resistance piece and the fasteners for tightening the first and second insulating plates and the resistance piece, the brushless synchronous motor can be attached to and removed from the rotary shaft. In this case, the bearings inserted into the ends of the rotor shaft are not required to be removed by fixing them with bolts inserted into the mounting legs, and the first and second insulating plates and the resistance piece are stripped. By adopting the shape, it is possible to minimize the mounting space occupied on the outer periphery of the rotor shaft, and it is possible to suppress an increase in the inertia of the rotor, so that it is possible to prevent an increase in the outer shape of the brushless motor,
It is possible to obtain a discharge resistor for a brushless motor that can be easily replaced.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a discharge resistor of a brushless synchronous motor of the present invention.

FIG. 2 is a right side view of FIG.

[Explanation of symbols]

1A, 1B ... Resistor piece, 2 ... Connection piece, 3, 3A ... Interlayer insulating plate, 4 ... Holding plate, 5 ... Double screw stud, 6 ... Insulating tube, 7
… Nuts, 8… Strip folding washers.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02K 19/36

Claims (2)

(57) [Claims] 1. A plurality of resistor pieces which are stacked via a first insulating plate and are connected in series on one side and which are connected in series, and one side of which is stacked on the outside of the resistor piece via a second insulating plate and the like. A pair of mounting legs whose sides are fixed to the rotary shaft of the brushless synchronous motor, one side of the mounting legs, one side of the mounting legs, and one side of the mounting legs, and the first side. A discharge resistor for a brushless synchronous motor, comprising a second insulating plate and a fastener for tightening the resistance piece. 2. The discharge resistor for a brushless synchronous motor according to claim 1, wherein the first insulating plate, the second insulating plate and the resistance piece are strip-shaped.