JPS6188746A - Device for fixing p bar to stator slot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to large rotating electrical machines, and more particularly to a stator for a single large power generator, usually the armature of a generator.

As is well known, large-scale generators are made of thin laminates made of magnetic materials.
The stators are assembled by stacking one on top of the other to form a generally annular assembly.

An array of axial slots is formed radially inwardly of the annular assembly. Each axial slot has at least one
It contains one, preferably two, armature bars forming part of an armature winding in which an electrical power is induced.

The trochanter is arranged to rotate coaxially within the stator. Typically, the rotor has a field winding, and the field vA winding is connected to a relatively low voltage (about 300 to about 700 volts) DC excitation source to produce a magnetic field that rotates at the same speed as the rotor. is excited by Conventional excitation sources include a shaft-mounted DC generator, a shaft-mounted alternating current generator that powers a rectifier, and an external excitation power source. The field where excitation F41 power from an external source rotates through the slip ring
Supplied to the windings. One type of external source that is prevalent is
Utilizes the AC output of the power generation itself. This output is passed through a transformer to the desired excitation voltage, then rectified and supplied to the field winding via a slip ring.

More recent exciter systems use voltage windings in three stator slots spaced, for example, by 120°. The three voltage windings, hereinafter referred to as rPJ bars, are subjected to the action of an alternating magnetic field, inducing an alternating current current in them. Therefore,
) three P-bars oriented mechanically at 120° constitute a three-phase source, the output of which is transformed as necessary to obtain the desired excitation voltage and then rectified, resulting in the The DC current can be supplied to the field winding via a slip ring.

This type of self-excited device was installed at the 43rd Motorcycle Plant, which was installed in Chicago, Illinois, from April 27th to 29th, 1981.
Paper presented at the annual American Power Conference rGENERREX-PPS
(voltage power supply). Rice Consin Power & Light, Exciting Device for Etsuio Wooter 5''. This GENERREX-PPS device reduces the space required for large-scale power generation and is a well-organized device that simplifies its maintenance. Control of the generator field voltage is achieved by high speed thyristor action. G
Further details of the ENERREX device are omitted since they are not relevant to the content of this invention.

The stator armature bar is typically clamped to the stator slot by means of a groove near the radially inner end of the stator slot and by tightly engaging a wedge in this groove. be.

The wedge exerts a radial force on the armature bar that counteracts the radial force on the armature bar caused by normal and abnormal magnetic and electrical forces applied to the armature bar.

The P-bar is typically placed radially inward of the wedge between the wedge and the surface of the rotor and secured in place using, for example, fiber roping pre-impregnated with a thermosetting resin. After installing the roping, the resin is cured. One such method of securing the P-bar in place is described in US Pat. No. 4,385,252.

Fixing the P-bar on top of the wedge comes at a cost. Manually wrapping ties every few inches around the P-bar and wedge and then curing the tie resin significantly increases the labor required to assemble the generator. Additionally, the stator may require servicing after the generator has been in use for a significant period of time. Since the three P bars are on the wedge, P
To replace the wedges in the three slots that house the bars, cut the roping ties, remove the P-bars, and then
It is necessary to remove and replace the wedge.

To remove the P bar, remove the cold fJI agent piping and l
;;The coil must be disconnected. P-bars are long, with a cross section of 1 or 2 inches and a length of 25 cm or more, so it takes a lot of practice to smooth them out when removing them. Afterwards, the P-bar must be reinstalled, tied in place, and cured. All of these sacrifices represent adverse labor costs and/or impact on planning.

One method of securing the P-bar to the stator slot is described in pending US Patent Application Serial No. 656.107, filed on the same date as this application. In that application,
Each stator slot has an inner pair of dovetail slots and an outer pair of dovetail slots. In all stator slots except the one housing the P-bar, the wedge
Fitted into a pair of dovetail slots to secure the dissector bar in place. In the stator slots that house the P-bars, the P-bars are mounted inside the slots above the armature bars, and wedges are mounted above the P-bars in a pair of outer dovetail slots.

It is desirable that the last few inches of the stator core taper outward to reduce the heating effect of axial stray magnetic fields on the ends of the stator core. This outward taper intersects the outer pair of dovetail slots, thus providing less or no support for the P-bar and the armature bar below it at the outer number 01 of the stator slot that houses the P-bar. . The outward taper may not intersect the inner pair of dovetail slots, so armature bars in stator slots that do not accommodate P-bars are satisfied at both axial ends of the stator. may not be supported.

OBJECTS AND SUMMARY OF THE INVENTION The object of the invention is to provide a technique for fixing P-bars to the stator of a generator, which overcomes the drawbacks of the prior art.

Another object of the present invention is to provide a technique for fixing a P-bar to the stator of a generator in which the stator core has an outward taper at both ends.

Another object of this invention is to provide a support bridge that retains radial forces on the outer ends of the P-bar and armature bar, which have their center cavities and are fixed under the wedge in the iM holes. It is.

Briefly, the present invention provides an apparatus for securing three voltage bars or P bars above an armature bar within the stator of a large generator. At least the stator slot accommodating the P-bar is more than dovetail slots in other stator slots used to secure the electron conductor bar in the stator slot.
It has a pair of dovetail slots radially closer to the cavity.

The outer taper at each end of the stator is 1t axially outside the dovetail slot of the stator slot that accommodates the P-bar! It intersects the i-section and weakens it, thus weakening and reducing the effectiveness of the support provided by such dovetail slots. Fit the inner end of the beam into the dovetail slot and onto the P bar. Secure the yoke over the outside edge of the beam. This yoke is secured to a stud in the base block extension located adjacent to the stator slot containing the P-bar. Wave springs between the beam and the P-bar apply a radial force to hold the P-bar and the armature bar firmly in the slot.

Another aspect of the invention provides an apparatus for securing conductors within stator slots of a stator core of a rotating electrical machine. Each stator slot has two pairs of opposing dovetail slots. All stator slots accommodate armature bars.

A small number of equally spaced stator slots also accommodate the P-bars above the armature bars. Install wedges in the radially outer dovetail slots of all stator slots that accommodate only armature bars. In the stator slot that accommodates both the armature bar and the P bar, the wedge attaches to the pair of dovetail slots at the radially inner pair of dovetail slots.

The above and other objects, features and advantages of this invention are as follows:
This will become clear from the explanation of the drawings below. The same reference numerals are used throughout the drawings for like parts.

Figure 1 shows a ty torpedo machine 10 that can use this invention.
It is shown. Power generation vessel 10 has a stator 12 having a stator core 14 assembled by laminating a large number of laminated plates of magnetic material.

The stacked laminates are axially compressed by applying an axial force to their ends through the single center flange 15.

A plurality of armature bars (not shown in FIG. 1) are axially distributed in slots (not shown in the drawings) located radially inwardly of the stator 12.

The armature bars are interconnected by end coils 16 that extend beyond the axial ends of stator core 14 . Stator 7
2 forms an annular body having a cylindrical opening 18 on its axis, in which a rotor 20 is rotatably mounted. For this reason, for example, a bearing 22 provided on the frame 24 of the generator rotatably supports the shaft 26 of the rotor 20.

Axial ff3! ! To avoid the heating effect of the 2Ii field on the ends of the stator 12, the outer pairs of cylindrical openings 18 at both ends of the stator 12 are tapered outwardly.

A simplified cross-sectional view of the generator 10 is shown in FIG. In order for rotor 20 to generate a magnetic field indicated by arrow 30,
It is excited by DC excitation applied to it. The radially inner surface of stator 12 has a large number of slots, of which only three stator slots 32 that accommodate P-bars 34 are shown. When the rotor 20 rotates in the direction shown by a driving threshold (not shown), a voltage is induced in the P bar due to the rotation of the magnetic field.The induced voltage is P
120° in electrical angle, corresponding to the physical spacing of the bars 34
They are out of phase. Those skilled in the art will appreciate that although rotor 20 has been illustrated as having a pair of 11 poles, this is not exhaustive of all possible options. Alternatively, for example, the rotor 20 can be configured to have two or more sets of angularly spaced magnets. In this type of power generation, the one-to-one correspondence between electrical angle and physical degree is not maintained. This invention is not affected by such 5U difference.

Continuing the description of this invention, the previously cited U.S. Pat.
．． A brief description of the technique for attaching P-bars 34 in accordance with No. 385,252 will be provided to assist in understanding the present invention.

Referring to FIG. 3, stator thrower 1-32 is 1
It has a pair of electrical defeat bars 36 (only the upper or radially inner one is shown). There are slots 38 on each side of the stator slot 32 which receive wedges 40 and allow the ? ffl iffff-36 to stator slot 32
Securely secure inside. It will be appreciated that the stator slot 32 extends radially inwardly a considerable distance beyond the top surface 42 of the wedge 40. This space is
All stator slots 32 are blanked except for the slot that accommodates the P-bar 34. A P-bar 34 is suitably insulated and placed in place within the stator slot 32, with the top and sides of the P-bar 34 and a portion of the wedge 40 as detailed in the above-cited US patents. It is tied in place on top surface 42 using a plurality of ties 44 passing underneath. The tie 44 is pre-impregnated with a thermosetting resin, and after being tied in this way, the resin is cured.

FIG. 4 shows a stator slot 32' that does not accommodate a P-bar 34, according to one embodiment of the invention. A pair of inner dovetail slots 46 are located in the same radial position occupied by dovetail slots 38 (FIG. 3). An outer pair of dovetail slots 48 is disposed radially inwardly than an inner pair of dovetail slots 46 . A wedge 40 is shown attached to the inner pair of dovetail slots 46 to secure the armature bar 36 in place within the stator slot 32. This view also shows the stator slot 32 which also accommodates the P-bar 34 along with the armature bar 36. P bar 34
is placed above the armature bar 36 under the wedge 40.

In order to give the stator slot 32 the necessary extra depth,
Wedges 40 are mounted in a pair of outer dovetail slots 48. This securely holds the P-bar 34 in place without the cost of installing ties or having to remove the P-bar 34 if the wedge 40 needs to be replaced.

Referring now to FIG. 1, the embodiment of the invention shown in FIG. A problem arises. The outer pair of dovetail slots 48 are closer to the radially inner ends of the stator slots 32 than the inner pair of dovetail slots 46 so that the outward taper 28
Shortly after this begins, the outward taper 28 cuts into the outer pair of dovetail slots 48 and the supporting action of the wedge 40 is removed. This is illustrated in the relevant cross-sectional views of FIGS. 5 and 6A-6E. As is conventional, the stator core 14 is assembled with small core packages 50 separated by gas passages 52 that are radially inward to the cold lJl gas. The gas passageway 52 typically has a plurality of I-shaped members which are compressed between their flanges by the compressive force applied to the stack of laminae at 8 of the stator core 14. is maintained. The outward taper 28 is applied to a plurality of core packages 50. For example, core package 50a is a full-depth core package, and its A as shown in FIG. 6A.
- The Arlf I plane shows that there is a normal scarp support material above the outer pair of dovetail slots 48a. The next core package 50b has a slightly shallower depth.
The step begins an outward taper 28.

As seen in section 8-8 of FIG. 6B, the mass of material above the outer pair of dovetail slots 48b is reduced, but the wedge 4
It still has enough material to substantially support 0. As the next iron core package 50C is added to the history, the outer pair of dovetails il'I''J7L48
There is little or no material above the wedge 40 to support the wedge 40 (Figure 6C). Next Tasshin Package 5
0d is further stepped and has no supporting effect on the wedge 40. The outermost core package 50e is stepped at the place where it contacts the adjacent gas passage 52, and
Furthermore, the divergence formation continues, and the spacer/spacer is tightened to the core package 50c by the core flange 15.
It terminates at block 54.

The inner pair of dovetail slots 46 are further away from the ends of the stator core 14 and are therefore relatively unaffected by the outward taper 28 of the core packages 50a-50d. A pair of inner dovetail slots 46e taper outward 2.
8 (J) in the core package 50e. This intersection occurs sufficiently close to the axially outer end of the stator core 14 that the stator slots that do not accommodate the P-bars 34 For armature bar 36 within 32',
The external supports of the end coils (not shown) extend beyond the intersection of the inner pair of dovetail slots 46c and the outwardly directed tapers 28 in an unsupported position in the stator core 14. Sometimes that's enough to overcome shortcomings. However,
As mentioned above, the pair of outer dovetail slots 48 are connected to the wedge 4.
0 is reduced and then eliminated at a substantial distance from the axially outer end of the stator core 14.

Spacer block extensions 5G are provided at spaced apart ones of the spacer blocks 54, and the photoelectric IXII 1
It supports a stud bolt 58 which is commonly used for attaching screws to screws (not shown).

The invention utilizes spacer block extensions 56 and studs 58, as will now be described.

FIG. 7 shows a plan view of the stator core 14.
In this figure, the P-bar 34 and the electric I-column bar 36 below it are shown in FIG.
0 holds it in place.

The wedge 40 is inserted at a point in the core package 50a or 50b (see FIGS. 5 and 6A or 6B) such that the outer pair of dovetail slots 48 leave suitable support material (see FIGS. 5 and 6A or 6B). indicates a point within core package 50b). A wedge burr 62 having the same cross-sectional shape as the wedge 40 is inserted into the outer pair of dovetail slots 48 and abuts the ends of the wedge 40. Spacer block extensions 56 are disposed on each side of stator slot 32 such that an inwardly extending portion 64 of each stud 58 extends axially inwardly toward the center of power generation 1a10. Yoke 66 has a pair of holes 67 into which inwardly extending portions 64 fit. A yoke 66 spans the outer end of the wedge beam 62.

A trapezoidal locking device 68 is fitted diagonally into the diagonal slot and secured in place by pin 72. A tie 74 is threaded around the stud 58 and through the hole 76 on each side of the yoke 66 to securely hold the rib 66 against the spacer block extension 56. The axially inner end of the wedge beam 62 is pressed against the P bar 34 by engaging with a pair of outer dovetail slots 4B in the core package 50b. The axially outer end of the wedge beam 62 is pressed against the P bar 34 by a yoke 66. Therefore, the P bar 34 is completely fixed in place under the wedge beam 62.

By way of example, the elements of beam support 60 are shown in an exploded view in FIG. 8, and in FIG. 1111!1 having a cross section 78 and a lower portion 80,
The lower portion has an angled flange that engages a pair of outer dovetail slots 48 at the axially inner end of the wedge 62. A tongue piece 82 with a flat upper surface 84 forms a wedge burr 62
It extends in the axial direction from The diagonal surface 86 is the upper part 78
88 and a flat top surface 84. A wave spring 90 is positioned below the wedge beam 62 and applies a substantially radial force that tends to secure the P-bar 34 in place. Wave spring 90 is shown in a relaxed condition in FIG. When installed, the undulating spring 90 is preferably completely flat between the wedge bar 62 and the P-bar 34, as shown in FIG. To prevent the high voltage insulation layer 92 of the P-bar 34 from being damaged by contact with the wave spring 90, a hard, non-abrasive filled strip 94 is placed between the wave spring 90 and the P-bar 34.

In particular, as shown in FIG.
It is parallel to the diagonal edge 86 of the wedge beam 62. Therefore, the trapezoidal locking device 68 can be inserted between the diagonal surface 96 and the diagonal surface 86, and the trapezoidal locking device 68 is prevented from coming off when it is held in place by the pin 72. be done.

When the stator core 14 is assembled, the embedded pole 1-58 is
Before installing the beam support 60, the spacer block 5
It is common to be welded or otherwise permanently attached to the 4. When installing the beam support 60, the wedge beam 62 has an underlying wavy spring 90 and a non-abrasive filler 1.
! In order to avoid touching the inner ends of the inwardly extending portions 64 which, together with the i-strips 94, are inserted into the outer pair of dovetail slots 48, the yoke 66 has a space occupied by the trapezoidal locking device 19. It must be placed so that it comes to Then hole 6
7 into the inwardly extending portion 64.

Inwardly extending portions 64 preferably have uncured resin during assembly, which resin is subsequently cured to securely secure yoke 66 in position relative to spacer block 54. After the yoke 66 is slid into the inwardly extending portion 64, this assembly method fills the empty trapezoidal space with the trapezoidal locking device 68; , York 66
and provides axial support to help keep the wedge beam 62 in its final position.

Referring to FIGS. 8 and 10, yoke 66 has a pair of legs 98 joined by a bridge 100 that spans tongue 82. Referring to FIGS.

The legs 98 have an angled angle 102 that matches the angle of the edge 104 of the generally flat top surface 84.

Therefore, when the tongue 82 is held down by the bridge 100, the bevel 102 and lip 104 tend to keep the axially outer end of the wedge 62 properly centered with respect to the stator slot 32. be.

Beam support 60 is preferably made of a non-magnetic material, most preferably a non-metallic material. With the exception of the stud 58, which is stainless steel, all parts of the beam support 60 are preferably made of a strong, hard matrix of resin and fabric.

Wedge beam 62 and yoke 66 are preferably made of glass fibers encased in a cured epoxy resin. The wavy spring 90 is also preferably made of epoxy resin and glass W4, selected from a type that maintains its elasticity over time. Alternatively, corresponding means for exerting a radial force on the P-bar 34 can be substituted, for example a body of elastomeric material or a spring with a crescent-shaped cross-section.

Filler strips 94 are selected to prevent damage to the high voltage insulation on the surface of P-bar 34. For this purpose, an Aiso II fiber-resin system such as a cotton-phenol laminate can be conveniently used.

The orientation of the fabric within the wedge beam 62 is preferably parallel to the axis of the wedge beam 62 for best resistance to bending forces. The orientation of the fabric within the yoke 66 is preferably normal to the axis of the wedge beam 62. In alternative embodiments of the invention, the wedge beam 62 and yoke 66 can be molded or otherwise formed into one integral piece instead of being two separate members. When molding, it is preferred to use chopped fibers to develop adequate strength in both the axial and normal directions.

Having described the preferred embodiment of the invention with reference to the drawings,
This invention is not limited to these embodiments per se, and those skilled in the art should be aware that various modifications can be made to this invention within the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a simplified axial sectional view of the power generator, and FIG. 2 is an end view of the power generation rock, showing the arrangement of the P-bar in the stator. FIG. 3 is a cross-sectional view of the stator slot, showing that the P-bar is mounted on the outside in a conventional manner. Figure 4 is the first
FIG. 2 is a cross-sectional view of a pair of adjacent stator slots taken along line IV-rV in the figure, showing how the electron bars are attached and showing the cases with and without the P bar. FIG. 5 is an end view of the stator slot showing how the tapered portion at the end of the stator intersects and obliterates the outer pair of dovetail slots. Figures 6A to 6E
The figure is a sectional view taken along lines A-A to E-E in Figure 5.
5 is a plan view of a portion of the stator of FIG. 5, showing a beam support according to one embodiment of the invention. FIG. 8 is an exploded view of a beam support according to one embodiment of the present invention, FIG. 9 is a sectional view taken along line IX--IX in FIG. 7, and FIG. 10 is a beam support in FIGS. 7 to 9. FIG. 3 is an end view of the body. Explanation of main symbols 28: Taper 32: Stator slot 34: P bar 36: Electron rod bar 46.48: Dovetail slot 60: Beam support 62: Wedge crest 66: Yoke 74: Tie 90: Wavy spring 102 .104: Diagonal edge

Claims (1)

Claims: 1) a stator slot of a generator stator has at least one pair of dovetail slots, the dovetail slots having at least one electrical radially disposed for receiving a child bar and a P bar, the stator having a taper at its outer end such that the taper intersects the pair of dovetail slots; and in an apparatus for securing a P-bar in a stator slot over at least one armature bar disposed in the slot, the axially inward first end of the P-bar being fitted into the dovetail slot; a beam having a slanted edge, a yoke acting to span an axially outer second end of the beam, and means for fixing the yoke to the axially outer end of the stator. , the securing means is operative to apply a radially outward force on the second end, and is further located between the beam and the P-bar to apply a generally radial force on the P-bar. Device with elastic means for applying. 2) The device according to claim 1), wherein the beam has a tongue at the second end, the yoke has first and second legs connected by a bridge, and the bridge has a tongue. A device adapted to be able to be fitted onto the tongue. 3) The device according to claim 2), wherein the tongue has a second diagonal edge, and the leg engages the second diagonal edge to cause the tongue to A device having an angled surface that acts to push it into a central position within said stator slot. 4) The device according to claim 2), wherein the beam has a first diagonal surface adjacent to the tongue, and the bridge has a second diagonal surface parallel to the first diagonal surface. and wherein the first and second diagonal surfaces are separated by an axial distance when the beam and yoke are installed in the operative position. 5) In the device according to claim 4), the locking piece inserted between the first and second diagonal surfaces acts to maintain the beam and the yoke in the axial position. Device. 6) The device according to claim 5, wherein the locking piece has a pin that passes through the locking piece and enters at least one of the beam and the yoke. 7) The device according to claim 1), wherein the beam, the yoke and the means for applying a radial force are made of non-metallic material. 8) The device according to claim 7), wherein the non-metallic material is a fiber within a cured resin. 9) The device according to claim 8), wherein the fibers include glass fibers. 10) In the device according to claim 9), the fibers in the beam are oriented parallel to the axis of the beam, and the fibers in the yoke are oriented perpendicular to the axis of the beam. A device that is 11) The apparatus according to claim 1), wherein the yoke has first and second legs connected by a bridge, and the means for securing the yoke includes a first leg adjacent to the stator slot. and a second spacer block, the first and second spacer blocks having first and second spacer block extensions, respectively, and the first and second spacer block extensions having a second spacer block. first and second studs, said first and second spacer block extensions having inwardly extending portions extending axially inwardly a predetermined distance, and said yoke having said first and second spacer block extensions extending axially inwardly a predetermined distance; a first part that can be fitted into the first and second inwardly extending parts;
and a second hole and means for coupling the first and second legs to the first and second spacer block extensions. 12) The device according to claim 1), wherein the elastic means comprises a wave spring. 13) The device according to claim 12), wherein the wavy spring is made of a non-magnetic material. 14) The device according to claim 1), wherein the elastic means comprises a wave spring and a non-wearing filler strip between the wave spring and the P-bar, so that there is no contact with the wave spring. A device designed to avoid damage to the P bar due to contact. 15) a plurality of stator slots, at least one armature bar in each said stator slot, a P-bar overlying at least one armature bar in at least one stator slot; first and second opposed dovetail slots in one stator slot; a wedge acting to apply a force; and a wedge at the outer end of the stator intersecting the first and second dovetail slots to apply a radial force to the P bar and the armature bar. said first and second dovetails at an axial location within said stator such that a taper such as to at least reduce the wedging capacity and a substantial portion of said first and second dovetail slots remain; a beam having an axially inner end thereof which can be fitted into a slot; a yoke acting to span the axially outer second end of the beam; means fixed to the radially outer end and acting to apply a radially outward force to the second end; and means between the beam and the P bar;
and elastic means applying a substantially radial force to the bar. 16) In laminates used in stacking to form a stator of a rotating electrical machine, slot-shaped openings in the laminates so as to form stator slots when assembled into the stator; a first dovetail slot within the opening at a first radius from the stator axis; and a second dovetail slot within the opening at a second radius from the stator axis. has
The first radius is effective to receive a wedge in the first dovetail slot for securing at least one armature bar within the slot, and the second radius is effective to receive a wedge in the first dovetail slot for securing at least one armature bar within the slot. and effective for receiving a wedge within said second dovetail slot for securing at least one armature bar, and thus by selecting which dovetail slot receives the wedge. A laminate in which an armature bar alone or a P bar and at least one armature bar can be fixed in the slot. 17) In a stator of a rotating electric machine, an annular stator core made of a magnetic material, a plurality of stator slots arranged in the axial direction on an inner surface of the stator core, and each of the stator slots. at least one armature bar located above the at least one armature bar, at least one of the stator slots receiving a P-bar above the at least one armature bar;
At least a second of the stator slots accommodates only the at least one armature bar and no P-bar; A pair and a second pair of opposing dovetail slots are provided, the first pair of dovetail slots being at a first radius from the core axis, and the first radius being at a first radius from the core axis. said second pair of dovetail slots having a second radius smaller than said first radius effective for positioning a wedge therein to secure at least one armature bar within said stator slot;
a second radius for positioning a wedge therein to secure the P-bar over the at least one armature bar within the first stator slot; Therefore, by selectively arranging wedges in the first pair or the second pair of dovetail slots, the armature bar alone or the armature bar and the P on the armature bar can be inserted into the stator slot.
A stator for a rotating electric machine that can be fixed with a bar.