Patent Grant
10804057
N/A
N/A
This disclosure is related to the field of switchgear apparatuses, and in particular, to replacement of mercury switches in a switchgear apparatus with alternative switch types, without requirement for adjustment of the switchgear apparatus itself.
Switchgear apparatuses are used as circuit breakers in industrial settings to switch power to certain circuits on or off. One commonly used type of switchgear apparatus utilizes an electric motor to move a mechanical breaker switch (mechanical switch, circuit breaker, etc.) into a bus for operation or out of the bus for non-operation (also known as “racking” the switch). When racked into the electrical bus, the mechanical breaker switch is installed and in position for operation as a circuit breaker. After racking-in the mechanical breaker switch, its electrical contacts can be moved into the closed position, where the mechanical breaker switch engages with corresponding electrical contacts so as to close the mechanical breaker switch and thereby complete a circuit. In operation, the electrical contacts can also be tripped or moved into the open position, where the electrical contacts are not engaged, resulting in the mechanical breaker switch being opened, and the circuit not being powered. When racked-out of the electrical bus, the mechanical breaker switch is not in operation and can be serviced or replaced.
So as to prevent overtravel by the mechanical breaker switch when racking it into or out of the bus, first and second position detection switches are used. When the mechanical breaker switch engages the first position detection switch (during rack-in travel) in a fashion sufficient to change state of the first position detection switch, the movement of the mechanical breaker switch into the bus by the electric motor is stopped. Likewise, when the mechanical breaker switch engages the second position detection switch (during rack-out travel) in a fashion sufficient to change state of the second position detection switch, the movement of the mechanical breaker switch by the electric motor is stopped.
The position detection switches in such switchgear apparatuses, particularly those switchgear apparatuses manufactured in the past, are mercury type tilt switches. Since it may now be desirable to replace these position detection switches with another type of tilt switch, such as one that is not mercury based, techniques for performing this replacement while not compromising operation of the switchgear apparatus are needed.
Disclosed herein is a method of replacing position detection switches in a breaker apparatus including a mechanical breaker switch that is movable between first and second position. The method includes moving the mechanical breaker switch to a position permitting removal of a first position detecting switch from a first support, with the first position detecting switch indicating whether the mechanical breaker switch is in the first position by transitioning between first and second states when disposed at or greater than a first threshold angle with respect to gravity. The first position detecting switch is removed and replaced with a first replacement position detecting switch without adjusting an angle of the first support with respect to gravity. The first replacement position detecting switch is adjusted such that it transitions between the first and second states at when disposed at or greater than the first threshold angle with respect to gravity, without adjusting the angle of the first support with respect to gravity.
Adjustment of the first replacement position detecting switch may be connecting a test device to the first replacement position detecting device, with the first replacement position detecting device indicating whether the first replacement switch is in first state or the second state. Adjusting the first replacement position detecting switch may include rotating the first replacement position detection switch until the test device indicate that the first replacement position detecting device transitions between the first and second states when disposed at or greater than the first threshold angle with respect to gravity.
Adjusting the first replacement position detecting switch may additionally or alternatively include disposing a sleeve about an exterior of the first replacement position detecting switch prior to replacement of the first position detecting switch with the first replacement position detecting switch, and testing whether the test device indicates that the first replacement position detecting device transitions between the first and second states when disposed at or greater than the first threshold angle with respect to gravity.
The first position detecting switch may be rated to handle a first voltage sufficient to control a motor that moves the mechanical breaker switch between the first and second positions, and the first replacement position detecting device may be rated to handle a second voltage lower than the first voltage and insufficient to control the motor. Control circuitry may be coupled to the first replacement position detecting switch so as to permit the first replacement position detecting device to control the motor.
The method may include removing a second position detecting switch that indicates whether the mechanical breaker switch is in the second position by transitioning between the first and second states when disposed at or less than a second threshold angle with respect to gravity. The second position detecting switch is replaced with a second replacement position detecting switch. The second replacement position detecting switch is adjusted such that it transitions between the first and second states at when disposed at or less than the second threshold angle with respect to gravity.
Removing the first position detecting switch may be removing a first position detecting switch of a first switch type, and replacing the first position detecting switch with the first replacement position detecting switch may be replacing the first position detecting switch of the first type with a first replacement position detecting switch of a second type different than the first type.
Replacing the first position detecting switch with the first replacement position detecting switch may be replacing the first position detecting switch with a first replacement position detecting switch of a same type as the first position detecting switch.
Also disclosed herein is an apparatus including a housing having a central opening defined therein, and a tilt activated switch disposed within the central opening of the housing. The central opening is angled with respect to a longitudinal axis of the housing such that rotation of the housing changes the angle of the tilt activated switch with respect to gravity.
The tilt activated switch may be of a rolling ball type, a mercury type, or any other suitable type.
The tilt activated switch may be rated to handle a second voltage. Control circuitry may be coupled to the tilt activated switch and enable the tilt activated switch to serve a load requiring a first voltage greater than the second voltage.
The control circuitry includes a voltage converter configured to convert the first voltage to the second voltage, and a relay circuit powered by the voltage converter and configured to switch an electric motor.
Also disclosed herein is a breaker apparatus including a mechanical breaker switch movable between racked-in and racked-out positions, an electric motor configured to move the mechanical breaker switch between the racked-in and racked-out when powered by a first voltage, and a first position detection apparatus. The first position detection apparatus includes a first support biased toward the closed position of the mechanical breaker switch and a first position detecting switch carried by the first support and for indicating whether the mechanical breaker switch is in the racked-out position, the first position detecting switch rated to handle a second voltage less than the first voltage. The first position detecting switch is adjustable so as to permit change of an angle thereof with respect to gravity without changing an angle of the first support with respect to gravity. Control circuitry includes a voltage converter configured to convert the first voltage to the second voltage, and a relay circuit powered by the voltage converter and configured to switch the electric motor.
These and other objects, features and advantages will become apparent as reference is made to the following detailed description, preferred embodiments, and examples, given for the purpose of disclosure, and taken in conjunction with the accompanying drawings and appended claims.
For a further understanding of the nature and objects of the present invention, reference should be made to the following detailed disclosure, taken in conjunction with the accompanying drawings, in which like parts are given like reference numerals, and wherein:
The following detailed description of various embodiments of the present invention references the accompanying drawings, which illustrate specific embodiments in which the invention can be practiced. While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains. Therefore, the scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.
In the following detailed description and the attached drawings, specific details are set forth to provide a thorough understanding of the present disclosure. However, those skilled in the art will appreciate that the present disclosure may be practiced, in some instances, without such specific details. In other instances, well-known elements have been illustrated in schematic or block diagram form in order not to obscure the present disclosure in unnecessary detail. Additionally, for the most part, specific details, and the like, have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present disclosure, and are considered to be within the understanding of persons of ordinary skill in the relevant art.
Referring initially to
Since it is desirable for the movement of the mechanical breaker switch 102 to stop when it is in the desired position to thereby prevent overtravel, position detecting switch apparatuses 108 and 110 are used to determine when the mechanical breaker switch 102 is in the desired position. In particular, the upper position detecting switch apparatus 108 detects when the mechanical breaker switch 102 is in a racked-in (ready for operation) position or detects when the mechanical breaker switch 102 is not in the racked-in position. The lower position detecting switch apparatus 110 detects when the mechanical breaker switch 102 is in the racked-out (not ready for operation) position or detects when the mechanical breaker switch 102 is not in the racked-out position.
The electric motor 104 ceases running based upon the inputs received from the position detecting switch apparatuses 108 and 110. For example, if the electric motor 104 is commanded to rack-in the mechanical breaker switch 102, it rotates the threaded shaft 106 so as to raise the mechanical breaker switch 102 (in the direction opposite to gravity), and ceases rotation when the position detecting switch apparatus 108 opens. Similarly, if the electric motor 104 is commanded to rack-out the mechanical breaker switch 102, it rotates the threaded shaft 106 so as to lower the mechanical breaker switch 102 (in the direction toward gravity) and ceases rotation when the position detecting switch apparatus 110 opens. Thus, overtravel of the mechanical breaker switch 102 is prevented. It should be noted that the opening or closing of the position detecting switch apparatuses (108 and 110) may be configured to have the electric motor (104) engage or disengage for either of the opening or closing operations, depending on the setup of the switch apparatuses.
This operation is best shown in
An engagement tab 122 extends from the side of the mechanical breaker switch 102 proximate to the support 120, and engages with the support 120 (as shown) as the mechanical breaker switch 102 is raised into the racked-in position. As can be seen in
In
An engagement tab 132 extends from the side of the mechanical breaker switch 102 proximate to the support 130, and engages with the support 130 (as shown) as the mechanical breaker switch 102 is lowered into the racked-out position. As the support 130 engages the engagement tab 132 as the mechanical breaker switch 102 is lowered into the racked-out position, the force exerted on the support 130 forces the support 130 downward, until the angle of the distal end of the support 130 with respect to the proximal end is sufficient to cause the lower position detecting switch 134 to open, at which point the electric motor 104 ceases motion. As shown in
The upper position detecting switch apparatus 108 and lower position detecting switch apparatus 110 on commonly used breaker apparatuses in the industry (such as the General Electric Magne-blast) are mercury based tilt switches. Due to concerns about mercury vial breakage, it may be desirable to replace mercury based tilt switches with other types of tilt switches, such as rolling ball based tilt switches, low volume mercury based tilt switches, or other suitable types of tilt switches.
Therefore, the Inventor has found it useful to remove existing mercury based tilt switches in the position detecting switch apparatuses 108 and 110 in such breaker apparatuses, in particular the General Electric Magne-blast, and to replace those mercury based tilt switches with rolling ball or low volume mercury based tilt switches 124, 134. However, rolling ball based tilt switches typically have lower voltage ratings than mercury based tilt switches.
Therefore, as shown in
While the replacement of the mercury based tilt switches in the position detecting switch apparatuses 108 and 110 with the rolling ball based tilt switches 124 and 134, in conjunction with the use of the voltage converter 150 and the relays 152, is effective in some scenarios, in other scenarios such direct replacement may require adjustment of the angle of the distal ends of supports 120 and 130 with respect to their proximal ends when in their resting positions so as to ensure that the replacement switches actuate at the proper positions. This not only may be difficult for a technician to accomplish, but due to the age of many commonly used breaker apparatuses, may result in the supports 120 and 130 being broken, resulting in a time consuming repair.
As a consequence, the Inventor has designed new rolling ball based tilt switches 124, 134 that may be adjusted, without requiring any adjustment or alteration of the supports 120, 130, so as to ensure actuation at the proper positions. These designs are shown in
Although only the rolling ball based tilt switch 124 will be described for brevity, it should be understood that the rolling ball based tilt switch 134 will have the same design. In
As shown in
An alternative embodiment of the rolling ball based tilt switch 124 is shown in
In other designs, the hole defined in the sleeve 138 may be parallel with the longitudinal axis of the sleeve 138, yet the exterior surface of the sleeve 138 itself may be cam shaped so that when the rolling ball based tilt switch unit 136, with sleeve 138 affixed, is inserted into the hole 140 of the housing 131, the longitudinal axis of the rolling ball based tilt switch unit 136 is angled with respect to the longitudinal axis of the housing 131, enabling the same adjustment of the angle of the longitudinal axis of the rolling ball based tilt switch 124 with respect to gravity as with the embodiments of
The steps taken by a technician to install the rolling ball based tilt switches 124 and 134 are as follows. First, the mechanical switch 102 is moved into a position in which both of the position detecting switch apparatuses 108 and 110 are open and there is sufficient room to permit disassembly thereof. Then, the old mercury based tilt switches are removed and replaced with the rolling ball based tilt switches 124 and 134. Next, a tester (shown as reference 154 in
It should be appreciated that there may be additional mercury tilt based switches in the breaker apparatus 100 that may be replaced with the rolling ball based tilt switch 124 and 134 as described above, together with the accompanying voltage converter 150 and relays 152 (if necessary).
In addition, in some cases, the tilt switch units 136 used may still be mercury switches, but containing less mercury than the conventional switches they replace. In such cases, the design of the switch 124 otherwise remains the same as described above. In fact, the tilt switch units may be of any type, and this disclosure is not meant to be limited to any particular type of tilt switches, and all suitable tilt switch designs are to be considered within the scope of this disclosure. In addition, although the above description is made with reference to an embodiment in which the mechanical breaker switch moves vertically to rack-in and to rack-out, it should be understood that this disclosure is usable with any mechanical breaker switch regardless of the direction of travel, including but not limited to horizontally racking mechanical breaker switches.
Additional details may be found as follows:
The Inventor will offer a retrofit kit along with other switchgear solutions, including cell side elevating cell maintenance kits (e.g., worm gears, chains, bearings, clutch adapters, spring, etc.) cell side primary disconnects, replacement elevating motors, and a test kit. To aid users in the installation of the retrofit system, the replacement upper and lower position detecting switches are a direct replacement for existing mercury tilt switches. Rather than replacing an entire length of wire from the mercury tilt switches, the replacement upper and lower position detecting switches may be equipped with pre-terminated wires and a splice connection to minimize the effort required for installation. See e.g.,
Since the retrofit system will be using existing wiring from the replacement upper and lower position detecting switches to the electrical enclosure and the voltage converter will be drawing power from an elevating motor cubicle control circuit (and the replacement upper and lower position detecting switches and relays/contactors will be drawing power from the voltage converter, an electrical enclosure housing the voltage converter and relays/contactors will mount between the elevating motor cubicle control circuit voltage power supply and a plug supplying operating voltage to the elevating motor. See e.g.,
The electrical enclosure may house the voltage converter and a circuit board housing the interposing relays/contactors for the voltage control of the elevating motor cubicle and current requirements of the elevating motor may be used to handle switching the elevating motor. The circuit board (and the interposing replays/contactors) will be drawing power from the voltage converter.
The retrofit kit may be retrofitted into a General Electric Magne-blast or General electric M36 switchgear using a control scheme as shown in
The replacement upper and lower position detecting device has a first wire having a first end and a second wire having a second end. About 0.375 inches of insulation may be removed from the first end of the first wire and from the second end of the second wire.
Although the preceding description has been described herein with reference to particular circuits and embodiments, it is not intended to be limited to the particulars disclosed herein; rather, it extends to all functionally equivalent structures, methods, and uses, such as are within the scope of the appended claims.
The embodiments and examples set forth herein are presented to best explain the present invention and its practical application and to thereby enable those skilled in the art to make and utilize the invention. However, those skilled in the art will recognize that the foregoing description and examples have been presented for the purpose of illustration and example only. The description as set forth is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching without departing from the spirit and scope of the following claims. The invention is specifically intended to be as broad as the claims below and their equivalents.
Definitions
As used herein, the terms “a,” “an,” “the,” and “said” means one or more, unless the context dictates otherwise.
As used herein, the term “about” means the stated value plus or minus a margin of error or plus or minus 10% if no method of measurement is indicated.
As used herein, the term “or” means “and/or” unless explicitly indicated to refer to alternatives only or if the alternatives are mutually exclusive.
As used herein, the terms “comprising,” “comprises,” and “comprise” are open-ended transition terms used to transition from a subject recited before the term to one or more elements recited after the term, where the element or elements listed after the transition term are not necessarily the only elements that make up the subject.
As used herein, the terms “containing,” “contains,” and “contain” have the same open-ended meaning as “comprising,” “comprises,” and “comprise,” provided above.
As used herein, the terms “having,” “has,” and “have” have the same open-ended meaning as “comprising,” “comprises,” and “comprise,” provided above.
As used herein, the terms “including,” “includes,” and “include” have the same open-ended meaning as “comprising,” “comprises,” and “comprise,” provided above.
As used herein, the phrase “consisting of” is a closed transition term used to transition from a subject recited before the term to one or more material elements recited after the term, where the material element or elements listed after the transition term are the only material elements that make up the subject.
As used herein, the term “simultaneously” means occurring at the same time or about the same time, including concurrently.
All patents and patent applications, articles, reports, and other documents cited herein are fully incorporated by reference to the extent they are not inconsistent with this invention.
This application claims benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/618,452 entitled “Method for Replacement of Mercury Switches in Switchgear with Alternative Switch Types,” filed on Jan. 17, 2018.
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| Number | Date | Country | |
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| 20190221387 A1 | Jul 2019 | US |
| Number | Date | Country | |
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| 62618452 | Jan 2018 | US |
