FIELD OF THE INVENTION
[0001] The present invention relates to a three phase earthing switch and to a method for
providing a three phase earthing switch.
BACKGROUND OF THE INVENTION
[0002] An earthing switch is an important device in a medium voltage switchgear. The role
of the earthing switch is to safely interconnect working conductors to earth potential
in order that it is safe to operate and/or work closely to these conductors in what
can be restricted surroundings. There is however a need to improve performance, reduce
cost, and at the same time reduce complexity of earthing switches.
SUMMARY OF THE INVENTION
[0003] Therefore, it would be advantageous to have an improved technology for providing
a three phase earthing switch.
[0004] The object of the present invention is solved with the subject matter of the independent
claims, wherein further embodiments are incorporated in the dependent claims. It should
be noted that the following described aspects of the invention apply also for the
three phase earthing switch and for the method of providing a three phase earthing
switch.
[0005] In a first aspect, there is provided a three phase earthing switch, comprising:
- at least one base unit;
- three connectors; and
- three earth contacts.
[0006] The at least one base unit is configured to hold the three connectors. A first distil
end of each of the three connectors is configured to rotate with respect to the at
least one base unit. A second distil end of each of the three connectors comprises
a contact knife. The three earth contacts are configured to be mounted at three locations
that are mechanically independent from and spaced from the at least one base unit.
In a first mode of operation of the three phase earthing switch the three connectors
are not in contact with the three earth contacts. In a second mode of operation of
the three phase earthing switch the three connectors are moved such that the three
contact knifes are in contact with the three earth contacts.
[0007] In an example, the three locations of the earth contacts are adjustable to vary the
spacing from the at least one base unit.
[0008] Thus, the fixation points are freely adjustable in their distance from the at least
one base unit.
[0009] In an example, each of the three earth contacts has a recess configured to receive
a contact knife of a connector.
[0010] In an example, the at least one base unit is formed from three base units, wherein
each connector is held by and configured to rotate with respect to a corresponding
base unit. The three connectors are electrically connected to each other, and the
three base units are configured to be mounted at three locations spaced from each
other.
[0011] In an example, at least two of the three base units are configured such that locations
of two of the three base units are adjustable to vary the spacing between the three
base units.
[0012] In an example, a first exchangeable interconnecting bar is configured to electrically
connect a first one of the three base units to a second one of the three base units,
and a second exchangeable interconnecting bar is configured to electrically connect
the second one of the three base units to a third one of the three base units.
[0013] Thus, when the spacing between the three base units is varied, the interconnecting
bars can be changed to ones of the correct length.
[0014] In an example, the three phase earthing switch has an exchangeable shaft that is
held by the at least one base unit.
[0015] Thus, when the spacing between the three base units is varied, the shaft can be changed
to one of the correct length.
[0016] In an example, the shaft is fixedly held by the at least one base unit, and wherein
the three connectors are configured to rotate with respect to the shaft.
[0017] In an example, the shaft is configured to rotate with respect to the at least one
base unit, and wherein the three connectors are fixedly connected to the shaft.
[0018] In an example, a position indicator associated with the shaft is configured to indicate
when the three phase earthing switch is in a position associated with the second mode
of operation.
[0019] In an example, the earthing switch comprises movement limiting means.
[0020] In an example, the movement limiting means comprises at least one movement stopper
fixedly attached to the at least one base unit, and comprises at least one movement
limiting component fixedly attached to at least one of the three connectors. In a
transition from the first mode of operation to the second mode of operation at least
a first part of the at least one movement limiting component is moved toward the at
least one movement stopper.
[0021] In an example, in the second mode of operation the at least first part of the at
least one movement limiting component is configured to be in contact with the movement
stopper.
[0022] In an example, in a transition from the second mode of operation to the first mode
of operation at least a second part of the at least one movement limiting component
is moved toward the at least one movement stopper.
[0023] In an example, in the first mode of operation the at least second part of the at
least one movement limiting component is configured to be in contact with the movement
stopper.
[0024] In an example, the three phase earthing switch comprises at least one spring. Activation
of the at least one spring is configured to transition the three phase earthing switch
from the first mode of operation to the second mode of operation.
[0025] In an example, a first end of the at least one spring is connected to the at least
one base unit and configured to rotate with respect to the at least one base unit.
When the at least one spring is activated a second end of the at least one spring
is configured to interact with at least one of the three connectors to rotate the
three connectors.
[0026] In a second aspect, there is provided a method of providing a three phase earthing
switch, comprising:
- a) holding three connectors by at least one base unit, wherein a first distil end
each of the three connectors can rotate with respect to the at least one base unit,
and wherein a second distil end each of the three connectors comprises a contact knife;
- b) mounting three earth contacts at three locations that are mechanically independent
from and spaced from the at least one base unit; and
wherein the method of providing a three phase earthing switch comprises two modes
of operation:
- in a first mode of operation the three connectors are not in contact with the three
earth contacts; and
- in a second mode of operation the three connectors are moved such that the three contact
knifes are in contact with the three earth contacts.
[0027] The above aspects and examples will become apparent from and be elucidated with reference
to the embodiments described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Exemplary embodiments will be described in the following with reference to the following
drawings:
- Fig. 1
- shows a schematic representation of an example of a three phase earthing switch;
- Fig. 2
- shows a method of providing a three phase earthing switch;
- Fig. 3
- shows a detailed structure of an example of a three phase earthing switch; and
- Fig. 4
- shows a detailed structure of a part of the example of the three phase earthing switch
as shown in Fig. 3;
- Fig. 5
- shows a detailed structure of a part of the example of the three phase earthing switch
as shown in Fig. 3; and
- Fig. 6
- shows a detailed structure of a part of the example of the three phase earthing switch
as shown in Fig. 3.
DETAILED DESCRIPTION OF EMBODIMENTS
[0029] Fig. 1 shows an example of a three phase earthing switch 50, where optional features
are shown in dashed form. The three phase earthing switch comprises at least one base
unit 1, three connectors 4, and three earth contacts 12. The at least one base unit
is configured to hold the three connectors. A first distil end each of the three connectors
can rotate with respect to the at least one base unit. A second distil end each of
the three connectors comprises a contact knife. The three earth contacts are mounted
at three locations that are mechanically independent from and spaced from the at least
one base unit. In a first mode of operation, the three connectors are not in contact
with the three earth contacts. In a second mode of operation, the three connectors
are moved such that the three contact knifes are in contact with the three earth contacts.
[0030] In an example, at least one earthing wire 7 is electrically connected to at least
one of the connectors.
[0031] In an example, the three earth contacts when mounted at the three locations are not
in electrical connection with the at least one base unit. In other words, the earth
contacts are fixed on fixation points, which are mechanically and statically independent
from the at least one base unit.
[0032] According to an example, the three locations of the earth contacts are adjustable
to vary the spacing from the at least one base unit.
[0033] According to an example, each of the three earth contacts has a recess configured
to receive a contact knife of a connector.
[0034] According to an example. the at least one base unit is formed from three base units,
Each connector is held by and can rotate with respect to a corresponding base unit.
The three connectors are electrically connected to each other. The three base units
are mounted at three locations spaced from each other.
[0035] In an example, each connector is fixedly attached to a moving contact holder 5. Each
of the three moving contact holders is configured to rotate with respect to a corresponding
base unit.
[0036] In an example, each base unit comprises two bent pieces of metal 11.
[0037] According to an example, at least two locations of two of the three base units are
adjustable to vary the spacing between the three base units.
[0038] According to an example, a first exchangeable interconnecting bar 6 electrically
connects a first one of the three base units to a second one of the three base units.
A second exchangeable interconnecting bar 6 electrically connects the second one of
the three base units to a third one of the three base units.
[0039] According to an example, the three phase earthing switch comprises an exchangeable
shaft 2 that is held by the at least one base unit.
[0040] According to an example, the shaft is fixedly held by the at least one base unit,
and wherein the three connectors are configured to rotate with respect to the shaft.
[0041] According to an example, the shaft is configured to rotate with respect to the at
least one base unit, and wherein the three connectors are fixedly connected to the
shaft.
[0042] According to an example, a position indicator 8 associated with the shaft is configured
to indicate when the three phase earthing switch is in a position associated with
the second mode of operation.
[0043] In an example, the position indicator is configured to indicate when the three phase
earth switch is in a position associated with the first mode of operation.
According to an example, the earthing switch comprises movement limiting means 3 and
10.
[0044] According to an example, the movement limiting means comprises at least one movement
stopper 10 fixedly attached to the at least one base unit, and comprises at least
one movement limiting component 3 fixedly attached to at least one of the three connectors.
In a transition from the first mode of operation to the second mode of operation at
least a first part of the at least one movement limiting component 3 is moved toward
the at least one movement stopper 10.
[0045] According to an example, in the second mode of operation the at least first part
of the at least one movement limiting component 3 is configured to be in contact with
the movement stopper 10.
[0046] According to an example, in a transition from the second mode of operation to the
first mode of operation at least a second part of the at least one movement limiting
component 3 is moved toward the at least one movement stopper 10.
[0047] According to an example, in the first mode of operation the at least second part
of the at least one movement limiting component 3 is configured to be in contact with
the movement stopper 10.
[0048] According to an example, the three phase earthing switch comprises at least one spring
9. Activation of the at least one spring is configured to transition the three phase
earthing switch from the first mode of operation to the second mode of operation.
[0049] According to an example, a first end of the at least one spring is connected to the
at least one base unit and configured to rotate with respect to the at least one base
unit. When the at least one spring is activated a second end of the at least one spring
is configured to interact with at least one of the three connectors to rotate the
three connectors.
[0050] Fig. 2 shows a method 100 of providing a three phase earthing switch in its basic
steps. The method 100 comprises:
- in a holding step 110, also referred to as step a), holding three connectors 4 by
at least one base unit 1, wherein a first distil end each of the three connectors
can rotate with respect to the at least one base unit, and wherein a second distil
end each of the three connectors comprises a contact knife;
- in a mounting step 120, also referred to as step b), mounting three earth contacts
12 at three locations that are mechanically independent from and spaced from the at
least one base unit; and
wherein the method of providing a three phase earthing switch comprises two modes
of operation:
- in a first mode of operation the three connectors are not in contact with the three
earth contacts; and
- in a second mode of operation the three connectors are moved such that the three contact
knifes are in contact with the three earth contacts.
[0051] In an example, the three locations of the earth contacts are adjustable to vary the
spacing from the at least one base unit.
[0052] In an example, each of the three earth contacts has a recess configured to receive
a contact knife.
[0053] In an example, the at least one base unit is formed from three base units, wherein
each connector is held by and configured to rotate with respect to a corresponding
base unit. The three connectors are in electrical connection with each other, and
wherein the three base units are mounted at three locations spaced from each other.
[0054] In an example, at least two locations of two of the three base units are adjustable
to vary the spacing between the three base units.
[0055] In an example, a first exchangeable interconnecting bar is electrically connects
a first one of the three base units to a second one of the three base units, and wherein
a second exchangeable interconnecting bar electrically connects the second one of
the three base units to a third one of the three base units.
[0056] In an example, wherein the method comprises holding an exchangeable shaft by the
at least one base unit.
[0057] In an example, the method comprises fixedly holding the shaft by the at least one
base unit, and wherein the three connectors can rotate with respect to the shaft.
[0058] In an example, the method comprises movably holding the shaft by the at least one
base unit, where the shaft can rotate with respect to the at least one base unit,
and fixedly connecting the three connectors to the shaft.
[0059] In an example, the method comprises using a position indicator associated with the
shaft to indicate when the three phase earthing switch is in the second mode of operation.
[0060] In an example, the method comprises using movement limiting means.
[0061] In an example, using the movement limiting means comprises fixedly attaching at least
one movement stopper to the at least one base unit, and comprises fixedly attaching
at least one movement limiting component to at least one of the three connectors.
In transitioning from the first mode of operation to the second mode of operation
at least a first part of the at least one movement limiting component moves toward
the at least one movement stopper.
[0062] In an example, in the second mode of operation the at least first part of the at
least one movement limiting component comes into contact with the movement stopper.
[0063] In an example, in transitioning from the second mode of operation to the first mode
of operation at least a second part of the at least one movement limiting component
moves toward the at least one movement stopper.
[0064] In an example, in the first mode of operation the at least second part of the at
least one movement limiting component is in contact with the movement stopper.
[0065] In an example, comprising using at least one spring, wherein activating the at least
one spring causes the three phase earthing switch to transition from the first mode
of operation to the second mode of operation.
[0066] In an example, a first end of the at least one spring is connected to the at least
one base unit and can rotate with respect to the at least one base unit. Activation
of the at least one spring causes a second end of the at least one spring to interact
with at least one of the three connectors to rotate the three connectors.
[0067] Fig. 3 shows a detailed example of a three phase earthing switch 50, with Figs. 4
and 5 showing a base unit of the three base units, where moving parts are shown in
Fig. 5. The three phase earthing switch has three base units 1, made of bent sheet
metal angles 11. The distance between the base units can be selected as necessary.
The base units hold the moving parts of the three phase earthing switch. The moving
parts are comprised of a shaft 2, movement limiting components 3, an moving contacts
(knives 4), moving contact holders 5, interconnecting bars 6, and earthing wires 7.
The shaft and interconnecting bars have lengths that are given by the distance between
the base units (phase pitch). The interconnecting bars and moving contacts (knives)
are made from copper and have a flat profile. A position indicator 8 is mounted on
the shaft. The moving parts are driven by a set of springs 9, in order that appropriate
closing force and speed is achieved. The end positions are set by the movement stopper
10 working in conjunction with the movement limiting components 3, shown in more detail
in Fig. 6 below. In this way, by having free fixing points the phase pitch can be
changed easily - base units and earthing contacts can be moved and phase interconnecting
bars and shaft can be easily changed with this adjustment. Only one moving contact
is required per phase, its design is rigid (3 fixing points), and it used flat Copper
phase interconnecting bars and as such is cost effective. Thus ease of assembly and
functional settings is provided, with rigidness and improved performance.
[0068] Fig. 6 shows the movement limitation principle of the three phase earthing switch,
with the earthing switch shown in an open state on the left and in a closed state
on the right.
[0069] It has to be noted that embodiments of the invention are described with reference
to different subject matters. In particular, some embodiments are described with reference
to method type claims whereas other embodiments are described with reference to the
device type claims. However, a person skilled in the art will gather from the above
and the following description that, unless otherwise notified, in addition to any
combination of features belonging to one type of subject matter also any combination
between features relating to different subject matters is considered to be disclosed
with this application. However, all features can be combined providing synergetic
effects that are more than the simple summation of the features.
[0070] While the invention has been illustrated and described in detail in the drawings
and foregoing description, such illustration and description are to be considered
illustrative or exemplary and not restrictive. The invention is not limited to the
disclosed embodiments. Other variations to the disclosed embodiments can be understood
and effected by those skilled in the art in practicing a claimed invention, from a
study of the drawings, the disclosure, and the dependent claims.
[0071] In the claims, the word "comprising" does not exclude other elements or steps, and
the indefinite article "a" or "an" does not exclude a plurality. A single processor
or other unit may fulfill the functions of several items re-cited in the claims. The
mere fact that certain measures are re-cited in mutually different dependent claims
does not indicate that a combination of these measures cannot be used to advantage.
Any reference signs in the claims should not be construed as limiting the scope.
1. A three phase earthing switch (50), comprising:
- at least one base unit (1);
- three connectors (4); and
- three earth contacts (12);
wherein, the at least one base unit is configured to hold the three connectors,
wherein a first distil end of each of the three connectors is configured to rotate
with respect to the at least one base unit;
wherein, a second distil end of each of the three connectors comprises a contact knife;
wherein, the three earth contacts are configured to be mounted at three locations
that are mechanically independent from and spaced from the at least one base unit;
and
wherein, in a first mode of operation the three connectors are not in contact with
the three earth contacts; and
wherein, in a second mode of operation the three connectors are moved such that the
three contact knifes are in contact with the three earth contacts.
2. Three phase earthing switch according to claim 1, wherein the three locations of the
earth contacts are adjustable to vary the spacing from the at least one base unit.
3. Three phase earthing switch according to any of claims 1-2, wherein each of the three
earth contacts has a recess configured to receive a contact knife of a connector.
4. Three phase earthing switch according to any of claims 1-3, wherein the at least one
base unit is formed from three base units, wherein each connector is held by and configured
to rotate with respect to a corresponding base unit, wherein the three connectors
are electrically connected, and wherein the three base units are configured to be
mounted at three locations spaced from each other.
5. Three phase earthing switch according to claim 4, wherein at least two locations of
two of the three base units are adjustable to vary the spacing between the three base
units.
6. Three phase earthing switch according to any of claims 4-5, wherein a first exchangeable
interconnecting bar (6) is configured to electrically connect a first one of the three
base units to a second one of the three base units, and wherein a second exchangeable
interconnecting bar (6) is configured to electrically connect the second one of the
three base units to a third one of the three base units.
7. Three phase earthing switch according to any of claims 1-6, comprising an exchangeable
shaft (2) that is held by the at least one base unit.
8. Three phase earthing switch according to claim 7, wherein the shaft is fixedly held
by the at least one base unit, and wherein the three connectors are configured to
rotate with respect to the shaft.
9. Three phase earthing switch according to claim 7, wherein the shaft is configured
to rotate with respect to the at least one base unit, and wherein the three connectors
are fixedly connected to the shaft.
10. Three phase earthing switch according to claim 9, wherein a position indicator (8)
associated with the shaft is configured to indicate when the three phase earthing
switch is in a position associated with the second mode of operation.
11. Three phase earthing switch according to any of claims 1-10, wherein the earthing
switch comprises movement limiting means (3, 10).
12. Three phase earthing switch according to claim 11, wherein the movement limiting means
comprises at least one movement stopper (10) fixedly attached to the at least one
base unit, and comprises at least one movement limiting component (3) fixedly attached
to at least one of the three connectors, wherein in a transition from the first mode
of operation to the second mode of operation at least a first part of the at least
one movement limiting component is moved toward the at least one movement stopper.
13. Three phase earthing switch according to claim 12, wherein in the second mode of operation
the at least first part of the at least one movement limiting component is configured
to be in contact with the movement stopper.
14. Three phase earthing switch according to any of claims 12-13, wherein in a transition
from the second mode of operation to the first mode of operation at least a second
part of the at least one movement limiting component is moved toward the at least
one movement stopper.
15. Three phase earthing switch according to claim 14, wherein in the first mode of operation
the at least second part of the at least one movement limiting component is configured
to be in contact with the movement stopper.
16. Three phase earthing switch according to any of claims 1-15, comprising at least one
spring (9), wherein activation of the at least one spring is configured to transition
the three phase earthing switch from the first mode of operation to the second mode
of operation.
17. Three phase earthing switch according to claim 16, wherein a first end of the at least
one spring is connected to the at least one base unit and configured to rotate with
respect to the at least one base unit, and wherein when the at least one spring is
activated a second end of the at least one spring is configured to interact with at
least one of the three connectors to rotate the three connectors.
18. A method (100) of providing a three phase earthing switch, comprising:
a) holding (110) three connectors (4) by at least one base unit (1), wherein a first
distil end each of the three connectors can rotate with respect to the at least one
base unit, and wherein a second distil end each of the three connectors comprises
a contact knife;
b) mounting (120) three earth contacts (12) at three locations that are mechanically
independent from and spaced from the at least one base unit; and
wherein the method of providing a three phase earthing switch comprises two modes
of operation:
in a first mode of operation the three connectors are not in contact with the three
earth contacts; and
in a second mode of operation the three connectors are moved such that the three contact
knifes are in contact with the three earth contacts.