Power generator and method for protecting the same

Abstract

To improve insulation and rust prevention of a stator and a rotor of a power generator.SOLUTION: An insulating coating film is formed on a laminated core 32 of at least one of stators 21, 31 or rotors 26, 36 of a power generator 1 by cation electrodeposition coating, an insulating bobbin 33 is attached to a teeth portion 32b of a laminated core 32 after the electrodeposition coating, and a coil 34 is wound about the bobbin 33. After the coil 33 is wound, the laminated core 32, the bobbin 33, and the coil 34 are impregnated and coated with varnish and dried, then the laminated core 32, the bobbin 33, and the coil 34 are coated together with the varnish impregnation coating film.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for protecting a generator and a generator protected by said method, and more specifically to a method for protecting a generator which not only improves the insulation performance between the core and coil provided in the stator or rotor of the generator, but also protects the stator or rotor from water, dust, etc., thereby improving the rust prevention performance, and a generator equipped with a rotor or stator protected by said method.

[0002] In addition, some generators, such as synchronous generators with an exciter, are equipped with an exciter, which is a generator that generates the excitation current required to excite the main generator, in addition to the main generator.

[0003] In this manner, in a configuration in which a generator is provided as an auxiliary device in addition to the main generator, the generators to be protected by the present invention include not only the main generator but also the generator as an auxiliary device. [Background technology]

[0004] In generators, in order to suppress the generation of eddy currents that cause iron loss, laminated cores are used as the cores of the rotor and stator, formed by stacking multiple sheets of electromagnetic steel (hereinafter referred to as "core sheets") punched into a specified shape, and the rotor and stator are formed by winding coils around the teeth of this laminated core.

[0005] The windings used for the coils are so-called "enameled wire," which is a conductive metal wire coated with an insulating varnish that is baked onto the surface. However, the coating on enameled wire is relatively weak and can peel off due to heat, impact, etc.

[0006] Therefore, in order to improve the insulation between the laminated core and the coil, the laminated core is sometimes painted with an insulating paint and the surface of the laminated core is covered with an insulating coating.

[0007] As the painting method for the laminated core, powder coating is often adopted, which can form a thick and strong coating film.

[0008] However, in powder coating, powder paint is applied to a workpiece that has been heated to the paint's melting temperature, thereby melting and adhering the paint to the surface of the workpiece. Therefore, when powder coating is performed on the aforementioned laminated core as a workpiece, when the laminated core is heated, the air present between the core sheets expands, or the moisture and oil remaining between the core sheets evaporates, and these gases are released from the gaps between the core sheets, which can cause defects such as air bubbles and pinholes in the coating film that is formed, reducing its insulating properties.

[0009] In this way, in order to prevent the occurrence of defects such as air bubbles and pinholes that can occur when a coating is formed on a laminated core by powder coating, Patent Document 1 listed below proposes forming a first layer of coating on the surface of the laminated core of the armature (rotor) of a rotating electric machine by electrocoating, thereby sealing the gaps between the core sheets on the outer surface side of the laminated core, so that even when the laminated core is heated in the subsequent powder coating to form the second layer of coating, gas is not released from the gaps between the core sheets, thereby preventing the occurrence of defects such as air bubbles and pinholes in the coating. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2020-195199 A Summary of the Invention [Problem to be solved by the invention]

[0011] According to the explanation in Patent Document 1, by painting a laminated core using the method described therein, a highly insulating coating film that is free of air bubbles and pinholes can be formed on the surface of the laminated core.

[0012] However, in order to form an insulating coating film using the method described in Patent Document 1, it is necessary to go through multiple painting processes using different painting methods, namely, forming a first layer of coating film by electrocoating and then forming a second layer of coating film by powder coating.This not only makes the process less efficient, but also requires a line for electrocoating and a line for powder coating to paint the laminated core, requiring a large initial investment and increasing the manufacturing costs of the laminated core.

[0013] Therefore, if the insulating coating for the laminated core could be performed, for example, only by electrochemical coating, it would be possible to improve workability and significantly reduce manufacturing costs.

[0014] However, when insulation between the laminated core and the coil is to be achieved primarily by an insulating coating formed on the surface of the laminated core, as in Patent Document 1, the necessary insulation properties cannot be ensured with a coating of several μm to several tens of μm formed by electrocoating, and therefore, in order to ensure insulation properties (dielectric strength voltage), it is essential to form a second layer of coating by powder coating after electrocoating (Patent Document 1

[0037] ).

[0015] In the powder coating used to form the second layer of coating, which is required in Patent Document 1, the coating tends to become thin in areas where it is difficult for the powder paint to adhere, such as the recessed corners formed on the base end side of the teeth of the laminated core, and if such thin areas exist in the insulating coating, these areas are likely to become the starting points for insulation breakdown.

[0016] On the other hand, if powder paint is applied to areas where it is difficult to apply powder paint, such as recessed corners, until an insulating coating of the required thickness is formed, not only will workability be further impaired, but the coating thickness will also become thicker in areas of the laminated core where the powder paint is easy to adhere to.

[0017] When a thick coating is formed in this manner, even if only partially, the external dimensions of the laminated core become larger accordingly. As a result, when a stator or rotor with such a laminated core is assembled into a motor casing, the stator will fit tightly into its mounting position inside the casing, making assembly less easy. Also, the gap between the stator and rotor will narrow, which may cause the coating to come into contact with other parts during assembly and be damaged. Damage to the coating in this manner may become the starting point for insulation breakdown.

[0018] As explained above, in the invention described in Patent Document 1, the necessary insulation cannot be obtained with just the coating film formed by electrocoating on the laminated core, so it is necessary to further form a thick coating film by powder coating on top of the coating film formed by electrocoating. However, as mentioned above, there are various problems associated with forming a thick coating film by powder coating after electrocoating.

[0019] Therefore, there is a demand for a method that simplifies the painting of the laminated core while ensuring insulation between the laminated core and the coil.

[0020] In addition, in the invention described in Patent Document 1, the laminated core is covered with an insulating coating, which prevents water droplets, dust, etc. from directly adhering thereto, and as a result, the laminated core can be considered to have anti-rust properties in addition to insulating properties.

[0021] However, when looking at the invention described in Patent Document 1 from the perspective of protecting the entire stator and rotor, only the laminated core is protected in the invention described in Patent Document 1, and no protection is provided for other components of the stator and rotor, such as the coils.

[0022] On the other hand, although the stator and rotor of the generator are housed within the generator casing and are protected to a certain extent by the casing, this casing is provided with an inlet and outlet for cooling air to cool the inside of the casing, and is configured to allow outside air to be introduced and pass through as cooling air.

[0023] As a result, there is a risk of rust (corrosion) on the stator and rotor due to contact with moist outside air that is introduced into the casing as cooling air, or due to the adhesion of water droplets and dust that have entered the casing along with the outside air.

[0024] In response to the adhesion of water droplets, dust, etc., the rotor is able to blow away the adhering water droplets and dust by using centrifugal force as it rotates. However, the stator which is attached in a stationary state to the outer periphery of the rotor, particularly the stator of the exciter which is located near the air intake, is not only prone to adhesion of water droplets, dust, etc., but also difficult to remove once water droplets and dust have adhered to it.

[0025] For this reason, with regard to the stator and rotor installed in the generator, especially the stator, it is necessary to consider a structure that takes into account not only the insulation and rust prevention of the laminated core, but also the protection of the entire stator and rotor (insulation, rust prevention, waterproofing, dustproofing, etc.).

[0026] Furthermore, by reviewing the overall structure of the stator and rotor from the perspective of protecting the entire stator and rotor, it is believed that the insulation between the laminated core and the coils can be further improved, even if the insulating coating formed on the laminated core has a simpler structure than the invention described in Patent Document 1.

[0027] Therefore, the present invention has been made to eliminate the drawbacks of the above-mentioned conventional technology, and aims to provide a method for protecting a generator that can not only ensure the necessary insulation between the laminated core and the coil even if the insulating coating on the laminated core provided on the stator or rotor of the generator is of a simple structure, but also improve the insulation and rust resistance of the entire stator or rotor even when water droplets, dust, etc. adhere to it, and a generator protected by said method. [Means for solving the problem]

[0028] The means for solving the problems are described below together with the reference numerals used in the description of the embodiment of the invention. These reference numerals are described in order to clarify the correspondence between the description of the claims and the description of the embodiment of the invention, and needless to say, are not used to restrict the interpretation of the technical scope of the present invention.

[0029] In order to achieve the above object, the protection method of the generator 1 of the present invention includes the following steps: A method for protecting a generator (1) having a stator (21, 31) fixed in a casing (10) and a rotor (26, 36) rotatably provided on the inner periphery of the stator (21, 31), the stator (21, 31) and the rotor (26, 36) having a laminated core (32) formed by laminating a plurality of core sheets (32a) formed into a predetermined shape, At least one of the stators 21, 31 or rotors 26, 36 (the stator 31 of the exciter 30 provided in the synchronous generator in the embodiment) an electrodeposition coating step of applying electrodeposition coating to the laminated core 32 to form an insulating coating film that covers the laminated core; an insulator attachment process for attaching an insulator 33 to the teeth portion 32b of the laminated core 32 after the electrodeposition coating process; a coil forming process for forming a coil 34 by winding a winding around the teeth portion 32b via the insulator 33 attached to the laminated core 31; and A varnish impregnation coating process in which the laminated core 32, the insulator 33, and the coil 34 after the coil forming process are impregnated with varnish and then dried, and the laminated core 32, the insulator 33, and the coil 34 are all covered with a varnish impregnated coating film; The present invention is characterized by carrying out the following (Claim 1).

[0030] After the varnish impregnation coating step, a rust-preventive coating film may be formed on the varnish impregnated coating film by further coating with varnish (claim 2).

[0031] The electrocoating carried out in the electrocoating process is preferably cationic electrocoating (Claim 3).

[0032] Furthermore, the generator 1 is provided with an intake port 12 for introducing cooling air into the casing 10 and an exhaust port 11 for exhausting the cooling air after cooling the inside of the casing 10, and the generator is a synchronous generator with an exciter that is provided with an exciter 30 disposed opposite the intake port 12 within the casing 10 near the position where the intake port 12 is formed, At least the electrocoating process, the insulator attachment process, the coil formation process, and the varnish impregnation coating process may be performed on the stator 31 of the exciter 30 (claim 4).

[0033] In addition, the generator 1 of the present invention is A generator 1 having a stator 21, 31 fixed in a casing 10 and a rotor 26, 36 rotatably provided on the inner periphery of the stator 21, 31, the stator 21, 31 and the rotor 26, 36 having a laminated core 32 formed by laminating a plurality of core sheets 32a formed into a predetermined shape, At least one of the stator or rotor, The laminated core 32 has a surface covered with an insulating coating film which is an electrocoating film; an insulator 33 attached to the teeth portion 32b of the laminated core 32 on which the insulating coating film is formed; A coil 34 is wound around the teeth portion 32b via the insulator 33, A varnish-impregnated coating that covers the laminated core 32, the insulator 33, and the coil 34 and that impregnates the gaps between the laminated core 32 and the insulator 33 and the gaps between the windings of the coil 34; (Claim 5).

[0034] In the generator 1 having the above-mentioned configuration, an anti-rust coating film may be further formed on the varnish-impregnated coating film (claim 6).

[0035] The insulating coating film that covers the laminated core 32 is preferably a cationic electrocoating film (claim 7).

[0036] The generator 1 can be a synchronous generator with an exciter, which is provided with an intake port 12 for introducing cooling air into the casing 10 and an exhaust port 11 for exhausting the cooling air after cooling the inside of the casing 10, and which is provided with an exciter 30 arranged opposite the intake port 12 near the position where the intake port 12 is formed in the casing 10, In this case, at least the stator 31 of the exciter 30 can be provided with the laminated core 32 on which the insulating coating is formed, the insulator 33, the coil 34 wound around the tooth portion 32b via the insulator 33, and the varnish-impregnated coating (Claim 8). Effect of the Invention

[0037] With the configuration of the present invention described above, the generator 1 of the present invention can provide the following remarkable effects.

[0038] The insulating coating on the laminated cores 32 of the stators 21, 31 and the rotors 26, 36 was performed using electrochemical coating, which has good paint adhesion and can be used to coat the gaps between the core sheets 32a. This made it possible to form a uniform insulating coating without any areas being left uncoated in a single painting process.

[0039] The insulating coating formed by this electrocoating is relatively thin, but the coil 34 is wound around the teeth portion 32b of the laminated core 32 on which the insulating coating is formed, via an insulator such as a bobbin or insulating paper, and after the coil 34 is attached, the laminated core, insulator 33, and coil 34 are coated with a varnish impregnated coating film formed by methods such as rotary dripping or immersion of varnish.In addition to attaching the insulator 33, the varnish can be impregnated into the gaps between the laminated core 32 and the insulator 33 and the gaps between the windings of the coil 34, thereby significantly improving the dielectric strength voltage between the laminated core 32 and the coil 34.

[0040] In addition, when the insulating coating film on the laminated core 32 is formed by powder coating instead of electrocoating as adopted in the present invention, or by a combination of electrocoating and powder coating as in the invention described in Patent Document 1 introduced earlier, it is difficult to form a uniform coating film with powder coating as described above, and the resulting film is thick. Therefore, when a configuration in which a bobbin is attached as an insulator 33 to the teeth portion 32b of the laminated core 32 as in the present invention is adopted, the outer shape of the teeth portion 32b becomes large, which causes the bobbin 33 to fit in tightly, and this can cause problems such as making the installation work difficult.

[0041] In contrast, by making it possible to form the insulating coating on the laminated core 32 solely by electrochemical deposition, the insulating coating can be formed relatively thin, and there is no problem such as reduced workability during assembly due to the bobbin 33 fitting too tightly.

[0042] Furthermore, when the stators 21, 31 and rotors 26, 36 are impregnated with varnish by rotary dripping or immersion, the varnish penetrates into the gaps between the various components and entirely covers the stators 21, 31 and rotors 26, 36. This improves not only the insulation of the laminated core 32, but also the insulation of the coil 34, and improves the rust resistance, waterproofing, and dust resistance of the entire stators 21, 31 and rotors 26, 36. Therefore, even when the generator 1 is used outdoors, for example, in an environment where water droplets and dust are sucked into the casing of the generator 1 along with the cooling air, it is possible to prevent water and dust from directly adhering to the laminated core 32, coil 34, etc., and a structure can be created that is less susceptible to rust and the associated accidents such as peeling of the insulating coating, electric leakage, and short circuits, thereby extending the life of the stators 21, 31 and rotors 26, 36.

[0043] In particular, in a configuration in which a rust-resistant coating film is formed by applying an additional layer of varnish on top of the varnish-impregnated coating film, further improvements in rust resistance, waterproofing, and dust resistance can be obtained.

[0044] As a result, by carrying out such treatment on at least the stator provided in the exciter of a synchronous generator with an exciter, a design is often adopted in which the stator is placed opposite the cooling air intake provided in the casing of the generator, and the life of the stator 31 of the exciter 30, which is prone to the adhesion of water droplets, dust, etc., can be significantly improved.

[0045] Furthermore, when the electrocoating is performed by anionic electrocoating, in which the laminated core 32 serves as the anode and the electrode serves as the cathode, the laminated core 32 serving as the anode will oxidize and dissolve, making it more susceptible to rust.

[0046] On the other hand, cathodic electrocoating, in which the laminated core 32 is used as the cathode and the electrode as the anode, makes it possible to form an insulating coating film that is highly adhesive and difficult to peel off, and also makes it possible to form an anti-rust coating film that is difficult to peel off and has excellent rust prevention properties. [Brief description of the drawings]

[0047] [Figure 1] FIG. 1 is a perspective view of a generator (synchronous generator with an exciter). [Diagram 2] FIG. 2 is a perspective view of a generator (synchronous generator with exciter) with the casing removed. [Diagram 3] FIG. 1 is a cross-sectional view of a generator (synchronous generator with exciter). [Figure 4] FIG. 2 is a perspective view of a laminated core (for use as a stator for an exciter). [Diagram 5] FIG. 1 is an explanatory diagram of how to attach a bobbin to a laminated core, (A) being before attachment and (B) being after attachment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0049] [Overall configuration of the generator] 1 and 2 show an example of the configuration of a synchronous generator with an exciter as an example of a generator 1 to be protected by the method of the present invention.

[0050] As shown in Figures 1 and 2, this generator 1 is equipped with a stator 21 and rotor 26 of the main generator 20 (in Figure 2, the rotor 26 of the main generator 20 is hidden by the stator 21 and cannot be seen), within a casing 10, and also houses a stator 31 and rotor 36 of an exciter 30, which is a generator that generates an excitation current to excite the rotor 26 of the main generator 20.

[0051] As shown in Figure 3, the rotor 26 of the main generator 20 and the rotor 36 of the exciter 30 are attached to a common rotating shaft 40 and are configured to rotate simultaneously. A rotational driving force generated by a driving source such as an engine (not shown) is input via a coupling 41 provided at the end of the rotating shaft 40 to rotate both rotors 26, 36, and the excitation current generated by power generation by the exciter 30 excites the rotor 26 of the main generator 20, thereby enabling the stator 21 of the main generator 20 to generate power.

[0052] A fan 42 for generating a flow of cooling air within the casing 10 is attached to the aforementioned rotating shaft 40, to which the rotor 36 of the exciter 30 and the rotor 26 of the main generator 20 are attached. Not only is power generation generated by rotating the rotating shaft 40, but it is also possible to introduce and exhaust cooling air into the casing 10.

[0053] In the embodiment shown in Figure 3, a fan 42 is provided on one end side of the rotating shaft 40 (right side of the paper in the figure), an exhaust port 11 is provided on the outer peripheral surface of the casing 10 at the outer periphery position of this fan 42, and an intake port 12 for introducing cooling air into the casing 10 is provided on the end surface of the casing 10 at the other end side of the rotating shaft (left side of the paper in the figure).When the fan 42 rotates along with the rotation of the rotating shaft 40, the cooling air sucked into the casing 10 through the intake port 12 can be discharged through the exhaust port 11 after cooling the equipment housed in the casing 10.

[0054] In the illustrated embodiment, the exciter 30 is disposed opposite the intake port 12 near the end wall of the casing 10 where the intake port 12 is provided as shown in FIG. 3, and the main generator 20 is accommodated within the casing 10 near the longitudinal center of the rotating shaft 40.

[0055] Because the generator 1 is configured in this manner, when the generator 1 is used, for example, outdoors, the exciter 30, which is positioned opposite the cooling air intake 12 formed in the end wall of the casing 10, is positioned in a position that is most likely to come into contact with water droplets, dust, etc. that are introduced into the casing 10 along with the cooling air.

[0056] Here, of the stator 31 and rotor 36 that make up the exciter 30, the rotor 36 rotates along with the rotating shaft 40, so even if water droplets or dust that are introduced into the casing 10 along with the cooling air adhere to it, the adhering water droplets or dust are blown away toward the outer periphery by the centrifugal force associated with the rotation and are thereby removed.

[0057] However, since the stator 31 of the exciter 30 is mounted in a stationary state within the casing 10, water droplets and dust adhering to the stator 31 will remain on the stator 31 without being removed.

[0058] Furthermore, the stator 31, which is arranged on the outer periphery of the rotor 36, is susceptible to the adhesion of water droplets and dust that are blown away by the rotor 36 due to centrifugal force, and therefore requires high insulating and rust-resistant properties, and it is desirable for the stator 31 to be waterproof and dust-proof.

[0059] Therefore, it is desirable that the protection method for the generator 1 of the present invention described below be performed on the stators 21, 31 and rotors 26, 36 of the main generator 20 and the exciter 30, particularly on the stator 31 of the exciter 30, and the following explanation will be given of an example of processing in which the stator 31 of the exciter 30 is the target for protection.

[0060] However, the protection method of the present invention may also be performed on the stator 21 of the main generator 20, and may also be performed on the rotors 26, 36 of the main generator 20 and the exciter 30.

[0061] [Protection method] FIG. 4 shows a laminated core 32 for a stator 31 of an exciter 30 of the generator 1 (synchronous generator with an exciter) described with reference to FIGS. 1 to 3.

[0062] This laminated core 32 is made by stacking multiple core sheets 32a, which are sheets of electromagnetic steel punched into a predetermined shape, and fixing the core sheets 32a to each other by welding, crimping, or other methods.As shown in Figure 4, the laminated core 32 has a shape in which a number of teeth portions 32b for attaching a coil 34 protrude inward from the inner circumference of an endless annular frame body.

[0063] The laminated core 32 thus formed by stacking the core sheets 32a of a predetermined shape and fixing the core sheets 32a to each other is then subjected to an "electrodeposition coating process" in which an insulating coating film is formed by electrodeposition coating, which electrically adheres paint to the laminated core 32 in an electrodeposition tank containing paint.

[0064] Incidentally, the laminated core 32 is washed as necessary before electrocoating to remove oil and other contaminants that may have adhered to the surface of the core sheet 32a during punching or the like.

[0065] In this embodiment, cationic electrocoating is performed as electrocoating for the laminated core 32 formed by stacking core sheets 32a made of electromagnetic steel plates in the aforementioned electrocoating tank containing paint, with the laminated core 32 as the cathode and the electrode as the anode, thereby adhering (electrodepositing) the epoxy-based paint to the surface of the laminated core 32.

[0066] By applying paint to the laminated core 32 using electrocoating (cationic electrocoating), which has good paint adhesion, the paint can also be applied to the gaps between the core sheets 32a that make up the laminated core 32.

[0067] The laminated core 32 with the paint applied in this manner is removed from the electrocoating tank and then heated to dry it and fix the paint to the surface, forming an insulating coating film that has high adhesion and penetrates into the gaps between the core sheets 32a.

[0068] In this way, an "insulator attachment process" is carried out in which an insulator 33 is attached to the teeth portion 32b of the laminated core 32, the surface of which has been formed with an insulating coating by electrochemical deposition, and a coil 34, which will be described later, is wound around the teeth portion 32b via the insulator 33.

[0069] This insulator 33 may be attached by attaching insulating paper (not shown) to the teeth portion 32b, but in this embodiment, a bobbin 33 made of an insulating material is attached to the teeth portion 32b of the laminated core 32 as shown in Figures 5(A) and (B).

[0070] In the embodiment shown in Figure 5, the bobbin 33 is configured to be easily attached to the teeth portion 32b by sandwiching the teeth portion 32b between the two divided bobbin halves 33a, 33b, but the structure of the bobbin 33 used is not limited to the configuration shown in the figure.

[0071] In the method of the present invention, as described above, the insulating coating film is formed on the laminated core 32 by electrochemical coating (cationic electrochemical coating), so that it is possible to form an insulating coating film that is uniform in thickness and relatively thin on the surface of the laminated core 32.

[0072] As a result, the dimensional change of the laminated core before and after the formation of the insulating coating is small, and there is little variation in size between products, so that problems such as the bobbin 33 fitting too tightly or too loosely are unlikely to occur.

[0073] A "coil forming step" is then carried out in which a coil 34 is formed by winding a required number of turns of enamel wire around the bobbin 33 attached to each tooth portion 32b of the laminated core 32 after the electrodeposition coating.

[0074] After the attachment of the bobbin 33 and coil 34 has been completed, the laminated core 32 is further impregnated and coated with varnish, for example by rotary dripping or immersion in the varnish, and then dried to coat the laminated core 32, bobbin 33, and coil 34 after electrocoating with an impregnated coating of varnish, in a "varnish impregnation coating process."

[0075] By applying the varnish by rotary dripping as described above as an example, the varnish can be impregnated into the gaps between the laminated core 32 and the bobbin 33 after electrocoating and into the gaps between the windings of the coil 34. Even if the insulating coating formed on the laminated core 32 as described above is a relatively thin one formed by electrocoating, the coil 34 is wound around the teeth portion 32b of the laminated core 32 via the insulating bobbin 33, and insulation is also provided by the varnish impregnated between the laminated core 32 and the bobbin 33 and between the windings of the coil 34, so that it is possible to improve the insulation between the laminated core 32 and the coil 34.

[0076] After the varnish is applied in this manner, it is dried and hardened to form an impregnated coating of the varnish.

[0077] By forming the varnish impregnated coating film in this manner, it is possible to prevent water, dust, etc. from entering the gap between the laminated core 32 and the insulator (bobbin in the embodiment) 33, the gap between the windings of the coil 34, etc., and by carrying out such a treatment on the stator 31 of the exciter 30, not only can the insulation between the laminated core 32 and the coil 34 be reliably achieved, but also it is possible to prevent the occurrence of rust and significantly extend the life of the stator 31, even though the stator 31 of the exciter 30 is located opposite the intake port 12 of the casing 10 as described above and is prone to adhesion of water droplets and dust. Note that the stator 31 on which the varnish impregnated coating film has been formed may be further coated with varnish to form an anti-rust coating film in order to improve the rust resistance. EXAMPLES

[0078] Next, the results of a test carried out to confirm the durability of a generator protected by the protection method of the present invention will be shown as an example.

[0079] [Test Method] The stator of an exciter for a synchronous generator with exciter (60 kVA) was protected by the method of the present invention (Example), and tested in accordance with the corrosion resistance test method (JASO M610) specified by the Japanese Automotive Standards Organization (JASO). Changes in the insulation of the stator were measured, and the rust prevention properties (state of rust formation) were visually confirmed.

[0080] The test was performed on the exciter stator 31 (single item; before installation in the generator) by subjecting it to one cycle of "salt spray", "dry", and "wet" conditions as shown in Table 1 below. The insulation resistance between the laminated core and the coil was measured after every three cycles, and the time it took for the insulation resistance to fall below 1 MΩ was measured.

[0081] The comparative example has the same structure as the example, except that no insulating coating (electrochemical coating) is formed on the laminated core.

[0082] [Table 1]

[0083] [Test Results] The results of the above corrosion resistance tests are shown in Table 2 below.

[0084] As is clear from the results in Table 2, it was confirmed that the stator (embodiment) protected by the method of the present invention was resistant to deterioration in insulation and to rust and corrosion, even when tested under extremely harsh conditions such as being exposed and exposed to salt water spray, without being housed within the motor casing.

[0085] [Table 2] [Explanation of symbols]

[0086] 1. Generator (synchronous generator) 10 Casing 11 Ventilation outlet 12 Air Intake 20 Main generator 21 Stator (of the main generator) 26 Rotor (of main generator) 30 Exciter 31 Stator (exciter) 32 Laminated core (for exciter stator) 32a Core Sheet 32b Teeth part 33 Insulator (bobbin) 33a, 33b Half body (of bobbin) 34 Coil 36 Rotor 40 Rotational Axis 41 Coupling 42 Fans

Claims

1. A method for protecting a generator having a stator fixed in a casing and a rotor rotatably provided on the inner periphery of the stator, the stator and the rotor having a laminated core formed by laminating a plurality of core sheets formed into a predetermined shape, comprising: At least one of the stator and the rotor is an electrodeposition coating step of applying electrodeposition coating to the laminated core to form an insulating coating film that covers the laminated core; an insulator attachment step of attaching an insulator to the teeth portion of the laminated core after the electrodeposition coating step; a coil forming process for forming a coil by winding a winding on the teeth portion through the insulator attached to the laminated core; and a varnish impregnation coating process in which the laminated core, the insulator, and the coil after the coil forming process are impregnated with varnish and then dried to cover the laminated core, the insulator, and the coil with a varnish impregnated coating film; 1. A method for protecting a generator, comprising:

2. 2. The method for protecting a generator according to claim 1, further comprising the step of forming an anti-rust coating film on the varnish impregnated coating film by coating with varnish after the varnish impregnating coating step.

3. 2. The method for protecting a generator according to claim 1, wherein the electrodeposition coating carried out in the electrodeposition coating step is cationic electrodeposition coating.

4. the generator is a synchronous generator with an exciter, the casing having an intake port for introducing cooling air into the casing and an exhaust port for exhausting the cooling air after cooling the inside of the casing, and the generator is a synchronous generator with an exciter disposed in the casing near the position where the intake port is formed, facing the intake port, The method for protecting a generator according to any one of claims 1 to 3, characterized in that the electrocoating process, the insulator attachment process, the coil formation process, and the varnish impregnation coating process are carried out on at least the stator of the exciter.

5. A generator having a stator fixed in a casing and a rotor rotatably provided on the inner periphery of the stator, the stator and the rotor having a laminated core formed by laminating a plurality of core sheets formed into a predetermined shape, At least one of the stator and the rotor is The laminated core has a surface covered with an insulating coating film which is an electrocoating film; an insulator attached to the teeth portion of the laminated core on which the insulating coating film is formed; a coil wound around the teeth via the insulator; a varnish-impregnated coating that covers the laminated core, the insulator, and the coil and that impregnates gaps between the laminated core and the insulator and gaps between the windings of the coil; A generator comprising:

6. 6. The generator according to claim 5, further comprising an anti-rust coating film formed on said varnish impregnated coating film.

7. 6. The generator according to claim 5, wherein the insulating coating film covering the laminated core is a cathodic electrocoating film.

8. the generator is a synchronous generator with an exciter, the casing having an intake port for introducing cooling air into the casing and an exhaust port for exhausting the cooling air after cooling the inside of the casing, and the generator is a synchronous generator with an exciter disposed in the vicinity of a position where the intake port is formed in the casing so as to face the intake port, A generator according to any one of claims 5 to 7, characterized in that at least the stator of the exciter comprises the laminated core on which the insulating coating is formed, the insulator, the coil wound around the teeth portion via the insulator, and the varnish-impregnated coating.

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