ELECTROPOLISHING AND ANODIZING METHOD FOR BRUSH HOLDER APPARATUS

- General Electric

A method for treating a surface of a brush holder apparatus, where the brush holder apparatus is configured for use in a dynamoelectric machine, includes an electropolishing step that electropolishes the surface of the brush holder apparatus. An anodizing step anodizes the surface of the brush holder apparatus. The electropolishing step is performed before the anodizing step.

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Description
BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to a method for electropolishing and anodizing a brush holder apparatus. Specifically, the subject matter disclosed herein relates to a method where the electropolishing is used as a pretreatment for the subsequent anodization of a brush holder apparatus.

Conventional dynamoelectric machines include a rotor having windings that conduct electrical current during operation of the machine. As the rotor rotates, rotating elements are used to conduct current to the rotor windings from a source external to the rotor. The rotating elements such as collector rings or commutators make contact with brushes to conduct the current. As the brushes are stationary with respect to the rotating elements, the brushes, which are made of carbon, wear due to friction and need periodic replacement.

Due to a desire to decrease downtime during operation of the dynamoelectric machine, brushes and brush holders are sometimes replaced during operation of the dynamoelectric machine. In order to replace brushes and brush holders safely, an operator uses a single hand (in order to avoid conducting electrical current through the operator's body). Conventional brush holders can be heavy and unwieldy, making brush replacement both difficult and dangerous.

BRIEF DESCRIPTION OF THE INVENTION

According to an aspect of the disclosure, a method for treating a surface of a brush holder apparatus, where the brush holder apparatus is configured for use in a dynamoelectric machine, includes an electropolishing step that electropolishes the surface of the brush holder apparatus. An anodizing step anodizes the surface of the brush holder apparatus. The electropolishing step is performed before the anodizing step. A cleaning step may be used to clean the surface of the brush holder apparatus to remove contaminants, and the cleaning step is performed before the electropolishing step. A cleaning step may also be performed before the anodizing step and after the electropolishing step. The electropolishing step may be performed with the following parameters: a 140° F. to 170° F. temperature, a voltage of 12 volts to 24 volts, an amperage of 15 amps per square foot to 50 amps per square foot, a phosphoric acid based electrolyte, and a dwell time of 4 minutes to 8 minutes. The electropolishing step may also include an agitating step that agitates the brush holder apparatus during the electropolishing step. The anodizing step may be performed with the following parameters, a chromic acid bath, a bath temperature of 100° F. to 130° F., a current density of about 3 amps per square foot, and a voltage of 18 volts to 24 volts. The anodizing step may be performed for a time to create an anodizing coating of 0.02 mils to 0.7 mils thick. The anodizing step may also be performed with the following parameters, a sulfuric acid bath, a bath temperature of 60° F. to 80° F., a current density of 5 to 18 amps per square foot, a voltage of 18 to 24 volts, and performed for a time to create an anodizing coating of 0.07 mils to 1.0 mils thick. The anodizing step may also be performed with the following parameters, a sulfuric acid bath, a bath temperature of 25° F. to 35° F., a current density of 24 to 40 amps per square foot, a voltage of 18 to 75 volts, and performed for a time to create an anodizing coating of 0.5 mils to 4.0 mils thick.

According to another aspect of the disclosure, a method for treating a surface of a brush holder apparatus, includes a cleaning step for cleaning the surface to remove contaminants. An electropolishing step is used for electropolishing the surface of the brush holder apparatus. An anodizing step is used for anodizing the surface of the brush holder apparatus. The electropolishing step is performed before the anodizing step, and the brush holder apparatus is configured for use in a dynamoelectric machine.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings that depict various embodiments of the disclosure, in which:

FIG. 1 illustrates a partial perspective view of a single brush holder installed on a collector horseshoe, according to an aspect of the present disclosure.

FIG. 2 illustrates a perspective view of the stationary support member, according to an aspect of the present disclosure.

FIG. 3 illustrates a perspective rear view of the stationary support member as shown in FIG. 2, according to an aspect of the present disclosure.

FIG. 4 illustrates a perspective front view of the brush holder, according to an aspect of the present disclosure.

FIG. 5 illustrates a perspective rear view of the brush holder, according to an aspect of the present disclosure.

FIG. 6 illustrates a bottom view of the brush holder and the cam members used to retain the brushes, according to an aspect of the present disclosure.

FIG. 7 illustrates a side view of the brush holder, according to an aspect of the present disclosure.

FIG. 8 illustrates a method for electropolishing and anodizing the brush holder apparatus, according to an aspect of the present disclosure.

FIGS. 9-12 illustrate the cleaning, electropolishing and anodizing steps for the brush holder apparatus, according to an aspect of the present disclosure.

It is noted that the drawings of the invention are not necessarily to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the disclosure provide for a method for electropolishing and anodizing a brush holder apparatus configured to conduct electrical current between a brush and a rotating element of a dynamoelectric machine (e.g., an electrical generator or electrical motor). In particular, aspects provide for a method where the electropolishing is done before the anodizing.

As described herein, conventional dynamoelectric machines include a rotor having windings that conduct electrical current during operation of the machine. As the rotor rotates, rotating elements are used to conduct current to the rotor windings from a source external to the rotor. The rotating elements such as collector rings or commutators make contact with brushes to conduct the current. As the brushes are stationary with respect to the rotating elements, the brushes, which are made of carbon, wear due to friction and need periodic replacement.

Due to a desire to decrease downtime during operation of the dynamoelectric machine, brushes are sometimes replaced during operation of the dynamoelectric machine. In order to replace brushes safely, an operator uses a single hand (in order to avoid conducting electrical current through the operator's body). Conventional brush holders can be heavy and unwieldy, making brush replacement both difficult and dangerous.

In contrast to conventional brush holders, aspects of the disclosure include a brush holder apparatus for a dynamoelectric machine having an anodized outer surface that provides electrical insulation. The insulating, anodized surface of the brush holder apparatus ensures that current flows through the brush and not the supporting components of the brush holder assembly. If the supporting parts of the brush holder assembly (e.g., the stationary support member, the brush holder, etc.) had current flowing through them, then a shock hazard would exist to an operator trying to manipulate the brush holder assembly.

FIG. 1 illustrates a partial perspective view of a single brush holder apparatus installed on a collector horseshoe, according to an aspect of the present disclosure. A brush mount or collector horseshoe 110 is mounted over a collector ring 120. The collector ring rotates along with the rotor (not shown). A plurality of brushes and corresponding brush holders are attached to the collector horseshoe and are distributed at least partially around the collector ring. In this example, only a single brush holder apparatus 100 is shown attached to the collector horseshoe 110. The brush holder apparatus 100 may be bolted or screwed to the collector horseshoe, or any other suitable method may be employed. The brush holder apparatus 100 includes a stationary support member 102 and a brush holder 104. The stationary support member 102 is configured for electrical connection to the collector mount (i.e., collector horseshoe 110), for example, by being fabricated of a conductive material or including a conductive material. The brush holder 104 is configured to retain the brush(es) (contained therein) at least in the axial and circumferential directions.

FIG. 2 illustrates a perspective view of the stationary support member 102, according to an aspect of the present disclosure. The stationary support member 102 includes at least one groove 210 (two are shown in FIG. 2) and a fork electrical connector 220. The fork electrical connector 220 may extend to one or both sides of the stationary support member, or alternatively the fork electrical connector may only be centrally located without extending to the sides of the stationary support member. A tapered slot 230 is located in an upper portion of the stationary support member 102, and the slot 230 is configured for cooperation with a locking pin 450 on the brush holder. The locking pin could also be replaced by a bar or latch or protrusion or disc with a ramped surface. The tapered nature of slot 230 acts to force the brush holder down into the connector 220 as the locking pin 450 is rotated. A bar 240 is located near a bottom end of the stationary support member 102, and this bar is configured to engage and restrain a cam on the brush holder 104. The bar 240 also serves to limit the distance the brush holder 104 can be inserted into the stationary support member 102. The brush holder 104 is fixed in position relative to the stationary support member 102 between the locking pin 450 at top and the bar 240 at the bottom. The bar 240 is fully contained within the profile of the stationary support member 102 and does not protrude past that profile. A plurality of holes 250 are provided and are configured to facilitate attachment of the stationary support member 102 to the collector mount (or collector horseshoe 110). The holes 250 may be internally threaded for use with mechanical fasteners, such as bolts or screws. In addition, the holes 250 may be provided on both sides of the stationary support member 102 so that they are configured to attach a plurality of stationary support members together in a stacked or side-by-side arrangement. This may be desired when multiple brushes are stacked side-by-side. For example, 3, 4, 5, 6, 7 or more brushes may be arranged at one circumferential location on collector horseshoe 110. A conductive bar 260 is located on one or more sides of the stationary support member 102. The conductive bar 260 is configured to provide electrical conductivity with the collector mount (collector horseshoe 110) and/or a second stationary support member (e.g., connected to the side of the first stationary support member).

FIG. 3 illustrates a perspective rear view of the stationary support member 102 as shown in FIG. 2, according to an aspect of the present disclosure. The conductive bar 260 passes through a portion of the stationary support member's main body 103, and is configured to provide electrical conductivity with the collector mount 110 and the fork electrical connector 220. This arrangement enables the stationary support member 102 to be fully electrically insulated and the current to pass from the horseshoe 110 to the fork 220 through the conductive bar 260. The holes 250 to mount to the horseshoe 110 are formed in conductive bar 260. In alternative embodiments, the conductive bar 260 may be lengthened so that multiple stationary supports 102 could be attached to the same (longer) conductive bar 260. The conductive bar 260 may be attached to the stationary support 102 and the fork electrical connector 220 via bolts (not shown) that run down through tabs 270 and into the stationary support, and into or through the conductive bar 260. In this example, one tab/boss 270 is shown on each side of the electrical fork 220. The fork electrical connector 220 may also be formed integrally with the conductive bar 260.

The stationary support member 102 may be configured to accept one, two (as shown), three, or more brush holders. One aspect would be a stationary support member that accepts one, two or three brushes, and multiple stationary support members and can be arranged side-by-side for applications needing a specific number of brushes at a given circumferential location on the collector horseshoe. The stationary support member 102 and/or the brush holder may be formed substantially (or comprised) of aluminum, an aluminum alloy, stainless steel or any other suitable electrically conductive or electrically non-conductive material as desired in the specific application. As one non-limiting example only, the stationary support member 102 and the brush holder 104 may be formed substantially (or comprised) of a passivated or anodized aluminum, or a passivated or anodized aluminum alloy. This material will give good strength while providing an electrically insulating or electrically semi-insulating material. It is desired to minimize current flow through the brush holder body and focus the current flow through the brushes and electrical path of the brush holder designed for this current flow. In addition, it would be desirable to minimize (or even block) any current flow to portions that may be grasped by a technician during insertion or removal. Also, it is desirable to avoid the possibility of current arcing directly from the collector ring 120 to the brush holder 104 or to the stationary support member 102 when a brush 432 is worn out and no longer able to be part of the path for the current. At least a portion of a surface of at least one of the stationary support member and the brush holder is configured to be substantially electrically insulating. For example, the handle of the brush holder should be substantially electrically insulating to protect a technician during insertion or removal of the brush holder on an operating machine. Alternatively, the stationary support member and the brush holder may be formed substantially (or comprised) of a powder coated or painted aluminum or a powder coated or painted aluminum alloy or a powder coated metallic or non-metallic material or a ceramic coated metallic or ceramic coated non-metallic material.

FIG. 4 illustrates a perspective front view of the brush holder 104, according to an aspect of the present disclosure. FIG. 5 illustrates a perspective rear view of the brush holder 104, according to an aspect of the present disclosure. The brush holder 104 is configured to be releasably affixed to the stationary support member 102. At least one rail 410 is configured to slide along groove 210. In the example shown the brush holder 104 includes two rails 410, one on each side of the brush holder. A knife electrical connector 420 (shown in FIG. 5), configured to mate with the fork electrical connector 220, is located on the rear of the brush holder 104. A brush retaining box 430 retains one or more brushes 432 in the axial and circumferential directions. In the example shown, box 430 retains two brushes 432. The brushes 432 are biased radially downward by brush springs 434. Apertures 431 form windows in the box 430 and allow the brushes 432 to be seen and visually monitored for wear.

The brush holder 104 includes a handle assembly 440 that includes an electrically insulating handle 442 and an electrically insulating guard 444 or shield that is located between the handle 442 and the brush connector leads 436. The brush connector leads 436 carry high voltage and current while the dynamoelectric machine is operating, so these present a hazard to be avoided. The electrically insulating handle 442 and guard 444 will prevent a technician's hand from coming into contact with the energized brush connector leads 436. The handle 442 and guard 444 may be comprised of plastic, rubber, epoxy/fiberglass laminate, fiberglass, or any other suitable electrically insulating material.

The locking pin 450 is configured for cooperation with the tapered slot 230 in the stationary support member 102. The handle assembly 440 can rotate, and as it rotates the locking pin 450 is rotated into, or out of, the tapered slot 230. The views of FIGS. 4 and 5 show the locking pin 450 and handle 442 oriented in the locked position. In this locked position the locking pin 450 is fully inserted into the slot 230 and the tapered surface drives the locking pin radially downward. In other words, the handle assembly 440 is configured to be rotated about 90 degrees, a 0 degree position configured so that the locking pin 450 is disengaged from the tapered slot 230 so that the brush holder 104 may be removed from the stationary support member 102. A 90 degree position (as shown in FIGS. 4 and 5) is configured so that the locking pin 450 is engaged in the tapered slot 230 so that the brush holder 104 is fully locked into operating condition on the stationary support member 102. By having the handle 442 oriented parallel to the locking pin 450 and having the locking pin 450 extend through the tapered slot 230, the operator can easily see that the brush holder 104 is fully inserted and locked in place within the stationary support 102.

A spring assembly 460 is housed within the handle assembly 440, and the spring assembly is mechanically connected to the brush terminal compression plate 470 (two of which are shown). The brush terminal compression plate may be one piece that extends through the shaft of the handle, but it could also be fabricated from two pieces. The brushes 432 are connected to the brush terminals 438 via brush connector leads (or pigtails) 436. The brush terminals 438 are electrically connected to the knife electrical connector 420. For example, the knife electrical connector includes an electrically conductive base member that extends under each brush terminal 438, thereby making an electrically conductive path. The spring assembly 460 biases the compression plates 470 downward and this downward pressure retains the brush terminals in place and against the base member of the knife electrical connector 420. This is particularly advantageous when the brush holder 104 is being inserted (or removed from) the stationary support member 102. It is advised to use only one hand when manually inserting or removing the brushes, and the spring assembly ensures that a second hand is not required to keep the brush terminals 438 in place. Once the brush holder 104 is fully inserted into the stationary support member, the handle 442 is rotated 90 degrees (into a locked position) and the tapered slot 230 forces the locking pin 450 (as well as brush holder 104) radially downward applying additional force onto the brush terminals 438. An advantage of this design is that the brush holder 104 is configured to clamp a brush terminal 438 between a terminal compression plate 470 and an opposing surface of the brush holder (i.e., the electrically conductive base member of knife electrical connector 420), so that the brush terminal is engaged or released manually, only by hand or without the use of any tools. All that is required is manual placement of the respective parts by hand. Minimizing or eliminating the use of specific tools can greatly simplify and increase the safety of working around dynamoelectric machines, especially when they are operating and energized.

As illustrated, the brush box 430 is configured to hold two brushes 432. However, the box 430 can be configured to hold one brush 432 (by reducing the width of the box) or three or more brushes (by increasing the width of the box and providing additional individual brush apertures). The brush terminal 438 includes a downward bend located at a proximal end thereof. This bend helps to keep the brush terminal in place under the compression plate 470. A hole or notch could also be provided in the brush terminal that cooperates with a complementary feature on the terminal compression plate 470 or the electrically conductive base member of knife electrical connector 420. For example, if the brush terminal 438 included a hole in the center thereof, the compression plate 470 could have a complementary pin located to engage the hole of the brush terminal. This complementary feature on the brush holder facilitates securing the brush terminal to the brush holder. The inverse could also be used, with the brush terminal having a complementary pin and the compression plate having the hole. With this arrangement, the brush holder 104 is configured to electrically and mechanically connect the knife electrical connector 420 to the brush terminal 438, while both the knife electrical connector 420 and the brush terminal 438 are electrically insulated from handle 442.

As the brush 432 wears down due to frictional contact with the rotor collector ring 120, the brush spring 434 will keep the eroding surface of the brush 432 in contact with the rotor collector ring 120. The brush spring 434 is configured to press the brush 432 radially downward and against the collector ring 120, because the spring 434 is designed with tension to re-coil itself. In this manner, the coil at the top of the spring 434 wants to re-tighten or coil downward, thereby applying a radially downward force to brush 432. The spring 434 is clipped on the bottom of the brush holder 104. For example, a lower part of main body portion 411 of the brush holder is where the brush spring 434 attaches to the brush holder. The bottom of the brush spring 434 is U-shaped, and the U-portion fits over and clips onto lower part of main body portion 411. The brush spring 434 is also configured to be located in-line with, or offset by 90 degrees from, the cam member 610 configured for restraining the brush 432 against the brush holder or box 430. This in-line arrangement is aligned so that any potential binding is reduced or eliminated and smooth operation is permitted between the spring 434, brush 432 and cam members 610.

FIG. 6 illustrates a bottom view of the brush holder 104 and the cam members 610 used to retain the brushes 432, according to an aspect of the present disclosure. A cam member 610 is operably connected to the shaft 620 near a bottom of the brush holder 104. The cam member 610 is configured to retain the brush 432 against the brush holder or box 430 until the brush holder 104 is fully inserted in the stationary support member 102. The cam member 610 may be constant-angle cam shaped, or have an arcuate toothed shape and is mounted with a spring 612 (e.g., a torsional spring) to shaft 620. The constant-angle cam shape and arcuate toothed shape may be consistent with logarithmic spiral geometry. That means that no matter how much the cam member 610 is rotated in order to reach the brush 432 surface, the cam 610 will contact the brush 432 with the same angle and same large force to resist sliding of the brush within the brush holder 104. Not all brushes may be exactly the same size so it is important that each cam member 610 is free to independently rotate on the shaft 620 to the fill the actual gap between the shaft 620 and the corresponding brush 432 surface.

FIG. 7 illustrates a side view of the brush holder 104, according to an aspect of the present disclosure. The knife electrical connector 420 is configured so that it slides into and makes electrical contact with the fork electrical connector 220. The knife electrical connector 420 extends down to a point below a top of the brush holder box 430.

FIG. 8 illustrates a method 800 for electropolishing and anodizing the brush holder apparatus, according to an aspect of the present disclosure. An optional cleaning step 810 cleans the surface of the brush holder apparatus 100 to remove contaminants. The contaminants may be particulate matter, grease or oils, or any other undesirable material currently on the brush holder apparatus. The brush holder apparatus may be cleaned or desmutted with a liquid acid solution. For example, the existing oxide layer is cleaned off in a bath of caustic soda, and after the caustic soda bath, the aluminum is washed in a bath made of half water and half 70% nitric acid.

In step 820 the surface of the brush holder apparatus is electropolished. In electropolishing the brush holder apparatus (or part thereof) is the anode (positive voltage) and the cathode is connected to a negative voltage terminal. The brush holder apparatus and cathode are immersed in an electrolyte bath and a voltage is applied for a specified time while the bath is maintained in a predetermined temperature range. The effect removes material from the surface of the brush holder apparatus, and polishes, deburrs or passivates the surface. The resulting electropolished surface provides a better surface for the application of a subsequent anodizing layer, which will have fewer defects and hence better electrical insulating performance. Example electropolishing parameters are, a phosphoric acid base bath/electrolyte, a bath temperature of about 140° F. to about 170° F., a DC rectified voltage of about 12 to 24 volts, an amperage of about 15 to 50 amps per square foot, and a dwell time (i.e., time spent in the bath exposed to DC voltage) of about 4 to 8 minutes. After the electropolishing step 820 the brush holder apparatus may be cleaned again in step 830, which may be similar to cleaning step 810.

In step 840, the electropolished brush holder apparatus (or part thereof) is now anodized. Anodization is an electrolytic passivation process used to increase the thickness of a natural oxide layer on the surface of metal parts. In anodizing the brush holder apparatus (or part thereof) is the anode (positive voltage) and the cathode is connected to a negative voltage terminal. The brush holder apparatus and cathode are immersed in an acid bath and a voltage is applied for a specified time while the bath is maintained in a predetermined temperature range. The effect creates an insulating oxide layer on the surface of the brush holder apparatus. The resulting anodized surface provides an insulating layer to ensure that current only flows through the brush and corresponding electrical connection, and not through undesired portions of the brush holder apparatus (e.g., the stationary supporting member, brush box or handle). Example anodizing parameters are provided for Type I, Type II and Type II anodizing layers. For a Type I anodizing treatment, a chromic acid bath is used with a bath temperature of about 100° F. to about 130° F., a DC rectified voltage of about 18 to 24 volts, an amperage of about 3 amps per square foot, and a dwell time sufficient to create an anodizing coating of about 0.02 mils (one mil equals 0.001 inches) to 0.7 mils thick. For a Type II anodizing treatment, a sulfuric acid bath is used with a bath temperature of about 60° F. to 80° F., a DC rectified voltage of about 18 to 24 volts, an amperage of about 5 to 18 amps per square foot, and a dwell time sufficient to create an anodizing coating of about 0.07 mils to 1.0 mils thick. For a Type III anodizing treatment, a sulfuric acid bath is used with a bath temperature of about 25° F. to 35° F., a DC rectified voltage of about 18 to 75 volts, an amperage of about 24 to 40 amps per square foot, and a dwell time sufficient to create an anodizing coating of about 0.5 mils to 4.0 mils thick.

FIGS. 9-12 illustrate the cleaning, electropolishing and anodizing steps for the brush holder apparatus 100 (or part thereof). In FIG. 9 a brush holder apparatus 100 is selected and contains contaminants 901 to be removed. The brush holder has a surface 910. Contaminants 901 are shown covering the entire surface, but contaminants 901 may only be present in selected areas on surface 910, with other areas of surface 910 being contaminant free. FIG. 10 shows the brush holder apparatus after cleaning, and the contaminants 901 have been removed. FIG. 11 shows the brush holder apparatus after electropolishing, and the electropolished surface 1110 is smoother than the previous surface 910. FIG. 12 shows the brush holder apparatus 100 after anodizing, and the anodized surface 1210 is now formed on the surface of the brush holder apparatus to a desired thickness.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. The terms “about” and “approximately” as applied to a particular value of a range applies to both values, and unless otherwise dependent on the precision of the instrument measuring the value, may indicate +/−10% of the stated value(s).

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A method for treating a surface of a brush holder apparatus, the brush holder apparatus for use in a dynamoelectric machine, the method comprising:

electropolishing the surface of the brush holder apparatus;
anodizing the surface of the brush holder apparatus; and
wherein the electropolishing step is performed before the anodizing step.

2. The method of claim 1, further comprising:

cleaning the surface to remove contaminants; and
wherein the cleaning step is performed before the electropolishing step.

3. The method of claim 1, further comprising:

cleaning the surface to remove contaminants; and
wherein the cleaning step is performed before the anodizing step and after the electropolishing step.

4. The method of claim 1, the electropolishing step performed with the following parameters:

a 140° F. to 170° F. temperature;
a voltage of 12 volts to 24 volts;
an amperage of 15 amps per square foot to 50 amps per square foot;
a phosphoric acid based electrolyte; and
a dwell time of 4 minutes to 8 minutes.

5. The method of claim 4, the electropolishing step further comprising:

agitating the brush holder apparatus during the electropolishing.

6. The method of claim 1, the anodizing step performed with the following parameters:

a chromic acid bath;
a bath temperature of 100° F. to 130° F.;
a current density of about 3 amps per square foot; and
a voltage of 18 volts to 24 volts.

7. The method of claim 6, the anodizing step performed for a time to create an anodizing coating of 0.02 mils to 0.7 mils thick.

8. The method of claim 1, the anodizing step performed with the following parameters:

a sulfuric acid bath;
a bath temperature of 60° F. to 80° F.;
a current density of 5 to 18 amps per square foot; and
a voltage of 18 to 24 volts.

9. The method of claim 8, the anodizing step performed for a time to create an anodizing coating of 0.07 mils to 1.0 mils thick.

10. The method of claim 1, the anodizing step performed with the following parameters:

a sulfuric acid bath;
a bath temperature of 25° F. to 35° F.;
a current density of 24 to 40 amps per square foot; and
a voltage of 18 to 75 volts.

11. The method of claim 10, the anodizing step performed for a time to create an anodizing coating of 0.5 mils to 4.0 mils thick.

12. A method for treating a surface of a brush holder apparatus, the method comprising:

cleaning the surface to remove contaminants;
electropolishing the surface of the brush holder apparatus;
anodizing the surface of the brush holder apparatus; and
wherein the electropolishing step is performed before the anodizing step, and the brush holder apparatus is configured for use in a dynamoelectric machine.

13. The method of claim 12, wherein the cleaning step is performed once before the electropolishing step and once before the anodizing step.

14. The method of claim 12, the electropolishing step performed with the following parameters:

a 140° F. to 170° F. temperature;
a voltage of 12 volts to 24 volts;
an amperage of 15 amps per square foot to 50 amps per square foot;
a phosphoric acid based electrolyte; and
a dwell time of 4 minutes to 8 minutes.

15. The method of claim 14, the electropolishing step further comprising:

agitating the brush holder apparatus during the electropolishing step.

16. The method of claim 14, the anodizing step performed with the following parameters:

a chromic acid bath;
a bath temperature of 100° F. to 130° F.;
a current density of about 3 amps per square foot; and
a voltage of 18 volts to 24 volts.

17. The method of claim 16, the anodizing step performed for a time to create an anodizing coating of 0.02 mils to 0.7 mils thick.

18. The method of claim 14, the anodizing step performed with the following parameters:

a sulfuric acid bath;
a bath temperature of 60° F. to 80° F.;
a current density of 5 to 18 amps per square foot; and
a voltage of 18 to 24 volts.

19. The method of claim 18, the anodizing step performed for a time to create an anodizing coating of 0.07 mils to 1.0 mils thick.

20. The method of claim 14, the anodizing step performed with the following parameters:

a sulfuric acid bath;
a bath temperature of 25° F. to 35° F.;
a current density of 24 to 40 amps per square foot;
a voltage of 18 to 75 volts; and
wherein the anodizing step is performed for a time to create an anodizing coating of 0.5 mils to 4.0 mils thick.
Patent History
Publication number: 20180298512
Type: Application
Filed: Apr 13, 2017
Publication Date: Oct 18, 2018
Applicant: General Electric Company (Schenectady, NY)
Inventors: Frank Austin Scalzo, III (New Hartford, NY), Eric Steven Buskirk (Scotia, NY), Curtis Maurice Hebert (Schenectady, NY)
Application Number: 15/486,637
Classifications
International Classification: C25D 11/16 (20060101); C25F 3/16 (20060101); C25D 11/08 (20060101); C25D 11/00 (20060101);