U.S. patent application number 15/960398 was filed with the patent office on 2018-09-13 for current converter with interchangeable head.
The applicant listed for this patent is PHOENIX CONTACT GMBH & CO. KG. Invention is credited to Markus BECKER, Jurgen HOBEIN, Andreas SENGER, Carsten THORNER.
Application Number | 20180261372 15/960398 |
Document ID | / |
Family ID | 49003773 |
Filed Date | 2018-09-13 |
United States Patent
Application |
20180261372 |
Kind Code |
A1 |
THORNER; Carsten ; et
al. |
September 13, 2018 |
CURRENT CONVERTER WITH INTERCHANGEABLE HEAD
Abstract
The subject matter herein pertains to a current transformer,
comprising a secondary coil, connection contacts for establishing
electrically conductive contact with the secondary coil from the
outside, and a housing having a housing body and a housing head,
wherein the secondary coil is accommodated in the housing body
and/or is attached to the housing body, and the connection contacts
of the secondary coil are provided on the housing head. According
to one implementation, a connecting mechanism is provided, by means
of which the housing head and the connection contacts can be
mechanically or electrically conductively detachably connected to
the housing body and to the secondary coil. A current transformer
is therefore provided, which is cost-effective to produce and is
flexible in terms of the use thereof.
Inventors: |
THORNER; Carsten; (Melle,
DE) ; SENGER; Andreas; (Altenbeken, DE) ;
HOBEIN; Jurgen; (Hameln, DE) ; BECKER; Markus;
(Paderborn, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PHOENIX CONTACT GMBH & CO. KG |
Blomberg |
|
DE |
|
|
Family ID: |
49003773 |
Appl. No.: |
15/960398 |
Filed: |
April 23, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14428964 |
Mar 17, 2015 |
9978495 |
|
|
PCT/EP2013/067382 |
Aug 21, 2013 |
|
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15960398 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01F 27/06 20130101;
H01F 5/04 20130101; H01F 27/402 20130101; H01F 27/02 20130101; H01F
27/306 20130101; H01F 38/28 20130101; H01F 27/04 20130101; H01F
27/29 20130101 |
International
Class: |
H01F 27/04 20060101
H01F027/04; H01F 27/29 20060101 H01F027/29; H01F 38/28 20060101
H01F038/28; H01F 5/04 20060101 H01F005/04; H01F 27/02 20060101
H01F027/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 17, 2012 |
DE |
10 2012 018 412.3 |
Claims
1.-10. (canceled)
11. A current transformer, comprising a secondary coil, a housing
having a flat housing body and a housing head, the flat housing
body having, in the center thereof, an opening for the passage of a
primary conductor, wherein the primary conductor, which is routed
through the flat housing body, mechanically fixes the housing body
in place such that the housing body cannot be released without the
primary conductor being removed, electrical connection contacts
located on the housing head for establishing electrically
conductive contact with the secondary coil from the outside, and
one or more connecting mechanisms, by which the housing head and
the electrical connection contacts can be mechanically and
electrically conductively detachably connected to the housing body
and to the secondary coil, wherein the secondary coil is disposed
within the flat housing body, wherein the connection contacts of
the secondary coil are provided on the housing head, wherein the
current transformer is a straight-through or slip-over transformer,
and wherein the housing head is removably mounted on top of the
housing body such that the housing head including the electrical
connect contacts for the secondary coil can be removed and replaced
without removing the housing body of the current transformer's
housing from the primary conductor.
12. The current transformer of claim 11, wherein the connection
mechanism used for the mechanical or electrical conductive
detachable connection is designed as a sliding mechanism and has a
combination of groove and spring.
13. The current transformer of claim 11, wherein the connection
mechanism for the electrical connection comprises electrically
conductive spring contacts, via which the connection contacts can
be connected to the ends of the secondary coil.
14. The current transformer of claim 11, wherein the current
transformer comprises a short-circuiter, via which the secondary
coil is short-circuited when the housing head is removed from the
housing body.
15. The current transformer according to claim 14, wherein the
connection mechanism is designed such that removing the housing
head from the housing body results in an automatic short-circuiting
of the short-circuiter.
16. The current transformer of claim 11, wherein the connection
contacts are designed as push-in contacts or screw-type
contacts.
17. The current transformer of claim 11, wherein a primary
conductor routed through the housing body to the secondary coil can
be operated with voltage differences between the primary conductor
and the secondary coil of over 1000V due to geometric dimensioning
of the spacings and/or dielectric dimensioning of the materials
between the primary conductor and the secondary coil.
18. The current transformer of claim 11, wherein the housing head
comprises protective electronics and/or functional electronics.
19. The current transformer of claim 14, wherein the connection
mechanism used for the mechanical or electrical conductive
detachable connection is designed as a sliding mechanism and has a
combination of groove and spring.
20. The current transformer of claim 14, wherein the connection
mechanism for the electrical connection comprises electrically
conductive spring contacts, via which the connection contacts can
be connected to the ends of the secondary coil.
21. A current transformer, comprising a secondary coil, a housing
having a flat housing body and a housing head, the flat housing
body having, in the center thereof, an opening for the passage of a
primary conductor, wherein the primary conductor, which is routed
through the flat housing body, mechanically fixes the housing body
in place such that the housing body cannot be released without the
primary conductor being removed, electrical connection contacts
located on the housing head for establishing electrically
conductive contact with the secondary coil from the outside, and
one or more connecting mechanisms, by which the housing head and
the electrical connection contacts can be mechanically and
electrically conductively detachably connected to the housing body
and to the secondary coil, wherein the secondary coil is disposed
within the flat housing body, wherein the connection contacts of
the secondary coil are provided on the housing head, wherein the
current transformer is a straight-through or slip-over transformer,
wherein the housing head is removably mounted on top of the housing
body; and wherein the connection mechanism used for the mechanical
connection is designed as a sliding mechanism and has a combination
of groove and spring.
22. The current transformer of claim 21, wherein the current
transformer comprises a short-circuiter, via which the secondary
coil is short-circuited when the housing head is removed from the
housing body.
23. The current transformer according to claim 22, wherein the
connection mechanism is designed such that removing the housing
head from the housing body results in an automatic short-circuiting
of the short-circuiter.
24. The current transformer of claim 21, wherein the connection
contacts are designed as push-in contacts or screw-type
contacts.
25. The current transformer of claim 21, wherein a primary
conductor routed through the housing body to the secondary coil can
be operated with voltage differences between the primary conductor
and the secondary coil of over 1000V due to geometric dimensioning
of the spacings and/or dielectric dimensioning of the materials
between the primary conductor and the secondary coil.
26. The current transformer of claim 21, wherein the housing head
comprises protective electronics and/or functional electronics.
27. The current transformer of claim 22, wherein the connection
contacts are designed as push-in contacts or screw-type
contacts.
28. The current transformer of claim 22, wherein a primary
conductor routed through the housing body to the secondary coil can
be operated with voltage differences between the primary conductor
and the secondary coil of over 1000V due to geometric dimensioning
of the spacings and/or dielectric dimensioning of the materials
between the primary conductor and the secondary coil.
29. The current transformer of claim 21, wherein the housing head
is removably mounted on top of the housing body such that the
housing head including the electrical connect contacts for the
secondary coil can be removed and replaced without removing the
housing body of the current transformer's housing from the primary
conductor.
30. The current transformer of claim 21, wherein the connection
mechanism for the electrical connection comprises electrically
conductive spring contacts, via which the connection contacts can
be connected to the ends of the secondary coil.
Description
CROSS-REFERENCE TO RELATED APPLICATION INFORMATION
[0001] This is a continuation of application Ser. No. 14/428,964,
filed Mar. 17, 2015, published as US/20150279542A1, which is a U.S.
371 National Stage Application of International Application No.
PCT/EP2013/067382 filed Aug. 21, 2013, published as WO2014/040830
A1, which claims priority from German Patent Application No. 10
2012 018412.3, filed Sep. 17, 2012, published as DE 10 2012018412,
which are incorporated herein by reference in entirety.
[0002] The invention relates to a current transformer, comprising a
secondary coil, connection contacts for establishing electrically
conductive contact with the secondary coil from the outside, and a
housing having a housing body (3) and a housing head, wherein the
secondary coil is accommodated in the housing body and/or is
attached to the housing body, and the connection contacts of the
secondary coil are provided on the housing head.
[0003] Current transformers are usually used to measure alternating
currents and function according to the transformer principle. A
transformer has a magnetic circuit--usually a ferrite or iron core,
around which the conductors of two different electric circuits are
wound. When an alternating voltage is applied to one of the
windings, a magnetic field builds up. When an alternating magnetic
field passes through a coil, an electric voltage is induced, the
level of which relative to the originally applied voltage
corresponds to the ratio of the numbers of turns of the
corresponding windings.
[0004] As compared to the secondary coil, the primary coil often
has very few turns or only one turn, which consists in the primary
conductor being routed through the secondary coil. This is called a
slip-over or straight-through transformer. The level of the current
induced in the secondary winding depends on the number of secondary
turns and is substantially proportional to the inducing primary
current. It is therefore very well suited for use as a measured or
manipulated variable.
[0005] In contrast to the Rogowski coil, a current transformer
comprises a usually toroidal, ferromagnetic core, which, due to the
bundling of the magnetic field, ensures high efficiency and high
accuracy in respect of the proportionality between the primary and
secondary currents.
[0006] Due to the high efficiency, secondary currents are generated
by a current transformer that are high enough that these secondary
currents are suitable for use, directly and without further
amplification, for the control or regulation of further switching
components.
[0007] This has the disadvantage, however, that a secondary circuit
of a current transformer must never be operated when open, since
the very high ("infinite") resistance between the open secondary
clamps results in very high voltages between said secondary clamps.
This would not only pose a danger to persons, but would also result
in voltage overloads and breakdowns, which can destroy the current
transformer.
[0008] An advantage of current transformers is the electrical
insulation of the primary and secondary currents. The secondary
circuit is therefore independent of the potential of the primary
circuit. Modifications of the secondary circuit that are basically
potential-free are therefore possible without the need to switch
off a primary circuit that has potential.
[0009] The motivation therefore exists, with respect to power
supply devices, for example, to be able to modify a circuit
arrangement of the secondary circuit in a current transformer that
is operating on the primary side without the current transformer
being destroyed by an interruption of the secondary circuit that
occurred in the meantime.
[0010] This goal can be achieved by temporarily short-circuiting
the secondary circuit of the current transformer before
disconnecting the connecting leads.
[0011] To this end, current transformers having appropriate
short-circuit devices for the manual or automatic bridging of the
connection contacts are known.
[0012] In other application scenarios, in which the primary current
can be easily switched off, a current transformer having an
integrated short-circuit device is suboptimal, however, since this
is too complex.
[0013] Rather, other application scenarios can be characterized in
that different installation conditions have different connection
requirements.
[0014] The problem is therefore that of providing a current
transformer, which can be cost-effectively provided regardless of
the application scenario.
[0015] The problem is solved according to the invention by the
features of the subject matter of claim 1. Advantageous embodiments
of the invention are defined in the dependent claims.
[0016] According to the invention, a current transformer is
therefore provided, said current transformer comprising a secondary
coil, connection contacts for establishing electrically conductive
contact with the secondary coil from the outside, and a housing
having a housing body and a housing head, wherein the secondary
coil is accommodated in the housing body and/or is attached to the
housing body, and the connection contacts of the secondary coil are
provided on the housing head, characterized in that a connecting
mechanism is provided, by means of which the housing head and the
connection contacts can be mechanically or electrically
conductively detachably connected to the housing body and to the
secondary coil.
[0017] The current transformer according to the invention offers
the advantage that the housing head, which comprises the connection
contacts of the current transformer, can be removed and therefore
replaced. This results in a number of further advantages.
[0018] The secondary coil is an essential component of a current
transformer, wherein said secondary coil is usually enclosed by a
housing body. In a common embodiment of a current transformer as a
straight-through or slip-over transformer, the secondary coil is
disposed in a flat housing body, which has, in the center thereof,
an opening for the passage of a primary conductor in the sense of
the primary coil. The primary conductor, which is routed through
the housing body, provides mechanical fixation of the housing body,
which cannot be released without the primary conductor being
removed.
[0019] The current transformer according to the invention can be
advantageously designed such that at least one part of the current
transformer, namely the housing head having the connection
contacts, can be replaced without the need to remove the primary
conductor. This reduces the amount of work required for performing
maintenance, retrofitting, or modification of an installation.
[0020] Another advantage results with regard for the production of
the current transformer. The housing body and the housing head can
be produced independently of one another and can be joined in a
subsequent production stage, upon delivery, or during
installation.
[0021] In the common embodiments, the secondary coil is
accommodated and enclosed by the housing body. Another object of
the invention is a partial enclosure of the secondary coil by the
housing body or an embodiment of the housing body as a fastening
element for the secondary coil.
[0022] This is advantageously designed such that the part of the
connection mechanism that is used for the mechanical connection is
designed as a groove-spring combination, for example in the form of
a sliding mechanism. When the dimensions are appropriate, such a
mechanical connection provides sufficient loadability with respect
to mechanical loads that occur during installation and
operation.
[0023] In an embodiment of the housing body and the housing head as
an injection-molded element, associated grooves or springs can be
realized in a cost-effective manner.
[0024] Advantageously, the part of the connection mechanism used to
electrically connect the connection contacts to the ends of the
secondary coil comprises electrically conductive spring
contacts.
[0025] Since frequent replacment of the housing heads is typically
unexpected, the spring contacts can be designed for a low number of
contactings and decontactings.
[0026] Advantageously, the current transformer also comprises a
short-circuiter, by means of which the secondary coil can be
short-circuited when the housing head is removed from the housing
body. Such a short-circuiter permits the housing head and the
housing body to be separated even while current is flowing in the
primary coil, without the risk of voltage overloads.
[0027] It is advantageous when the connection mechanism is designed
such that removing the housing head from the housing body results
in an automatic short-circuiting of the short-circuiter such that
the risk of operator error can be reduced.
[0028] In addition or as an alternative to a short-circuiter in the
housing body, the housing head in another advantageous embodiment
comprises a short-circuiter. As with the above-described
short-circuiter, this can also be designed to be manual or
automatic, wherein this short-circuiter is usually actuated when
connection leads are contacted to or decontacted from the current
transformer.
[0029] In another advantageous embodiment, a housing head for a
current transformer according to the invention comprises protective
electronics and/or functional electronics. This can also comprise
electronics for monitoring the secondary circuit. The impedance of
the secondary circuit can be monitored, for example, such that a
short-circuiter protects the current transformer against overload
when a predetermined threshold is exceeded.
[0030] Advantageously, the connection contacts of the housing head
are designed as push-in contacts or screw-type contacts. These can
be realized in a reliable and cost-effective manner. The specific
configuration can depend on the intended application, wherein
housing heads having different connection contacts can be provided
for the same current transformer.
[0031] Therefore, it is advantageous to design a set of housing
heads for a current transformer according to the invention, wherein
the connection mechanism is designed such that the housing body can
be alternatively connected to the housing heads in the set.
[0032] It is therefore possible to streamline production, since
uniform housing bodies can now be designed for different current
transformers having different connection techniques, wherein said
uniform housing bodies can be combined with the respectively
desired housing head in order to form the final product.
[0033] Furthermore, retrofits or expansions can be carried out on
existing installations such that a current transformer having a
housing head without short-circuit protection or without protective
electronics can be replaced with a new housing head having a
different and, possibly, expanded functionality without
considerable effort.
[0034] Finally, it is advantageous to standardize the connection
mechanism between the housing body and the housing head such that a
housing head can be combined with different housing bodies.
[0035] Advantageously, a set of housing bodies for a current
transformer according to the invention is therefore equipped with a
connection mechanism that allows the housing head to be
alternatively connected to the housing bodies of the set.
[0036] This embodiment also makes it possible to further streamline
the production of current transformers, since it is now possible to
provide uniform housing heads for current transformers, for
example, current transformers having different sizes and
performance classes.
[0037] For example, the same housing head could be combined with a
housing body for low-voltage applications and with a housing body
for high-voltage applications. Since the primary conductor and the
secondary coil are electrically insulated with respect to one
another, the dielectric strength of the current transformer is
determined by the dielectric separation of the primary conductor
and the secondary coil. Due to suitable dimensioning of the
spacings and/or the dielectric dimensioning of the materials (e.g.,
housing shell, air) between the primary conductor and the secondary
coil, the current transformer according to the invention can be
operated with voltage differentials between the primary conductor
and the secondary coil of over 1000V.
[0038] The advantage of being able to use the same housing head in
combination with different housing bodies is also useful when the
housing body must be partially removed in order to remove the head.
The housing body of a current transformer is often formed of two
complementary housing shells, namely an upper shell and a lower
shell. In an embodiment having a simple design, the housing head,
which is considered to be a single part, is installed before the
housing shells are joined. The housing head can be fixed by means
of a peripheral groove-spring connection, which is closed by
joining the housing shells. As a result, the connection between the
housing head and the housing body can be loaded in any direction
with relative pressure, tensile, or shear forces.
[0039] The invention is described in greater detail in the
following with reference to the attached drawings and preferred
embodiments.
[0040] In the drawings
[0041] FIG. 1 shows a current transformer according to a preferred
embodiment of the invention, separated into the housing body and
the housing head,
[0042] FIGS. 2A-2C show current transformers according to preferred
embodiments of the invention showing the housing body and the
housing head joined (FIG. 2A), a housing body alternatively
connected to plural housing heads (FIG. 2B), and a housing head
alternatively connected to plural housing bodies (FIG. 2C).
[0043] FIG. 3a,b show a housing head of a current transformer
according to a preferred embodiment of the invention,
[0044] FIG. 4a,b show a housing head of a current transformer
according to a preferred embodiment of the invention, and
[0045] FIG. 5-6 show current transformers according to other
preferred embodiments of the invention, FIG. 5 comprising a housing
body and an alternative embodiment of a housing head, FIG. 6
showing the short-circuiting device.
[0046] FIG. 1 shows a first embodiment of a current transformer 1
according to the invention, separated into a housing body 3 and a
housing head 2. The depiction is perspective and the housing head 2
is shown raised above the installation site thereof on the housing
body 3.
[0047] The housing head 2 comprises two connection contacts 4, via
which the secondary coil--not visible--can be contacted in the
housing body 3 when the housing head 2 is installed. As the
mechanical part of a connection mechanism, the housing of the
housing head 2 comprises a groove 5, into which a spring 6 of the
housing body 3 can engage. In the embodiment shown, the groove 5
encircles the housing head 2 and the spring 6 of the housing body 3
is correspondingly annular such that the installed housing head 2
has no freedom of motion relative to the housing body 3. The
peripheral spring 6 prevents horizontal shearing of the housing
head 2 relative to the housing body 3, and the engagement of the
spring 6 into the groove 5 prevents a change in vertical position.
In this embodiment, the housing body 3 formed of two housing shells
must be opened in order to install the housing head 2.
[0048] FIG. 2A shows the current transformer 1 according to a
preferred embodiment of the invention with a first embodiment of a
housing head 2. The groove-spring design shown in FIG. 1 undergoes
mutual engagement in FIG. 2A and is covered by the upper edge of
the housing body 3. The connection mechanism may be designed such
that housing bodies and housing heads can be alternatively
connected to each other. FIG. 2B shows a connection mechanism
designed such that a housing head can be alternatively connected to
plural housing bodies of a set of housing bodies. FIG. 2C shows a
connection mechanism designed such that the housing body can be
alternatively connected to plural housing heads of a set of housing
heads.
[0049] FIG. 3a shows a first embodiment of a housing head 2 of a
current transformer 1 according to a preferred embodiment of the
invention, comprising a front housing head shell 10, a rear housing
head shell 11, and the connection contacts 4. The connection
contacts 4 designed as a screw-type contact 9 are fixed by joining
the front housing head shell 10 and the rear housing head shell 11
via webs located in the housing head shells 10, 11. Furthermore,
the connection contacts 4 comprise a spring contact 7, by means of
which a mating contact--which is not shown--in the housing body 3
can be contacted such that these, as the electrical part of the
connection mechanism, can enable the electrical connection of the
connection contacts 4 to the ends of the secondary coil.
[0050] FIG. 3b shows the first embodiment of a housing head 2
depicted in FIG. 3a, in the installed state.
[0051] FIG. 4a shows a second embodiment of a housing head 2' of a
current transformer 1 according to the invention, which comprises a
front housing head shell 10', a rear housing head shell 11', and
the connection contacts 4'. The connection contacts 4', which are
designed as push-in contacts 8, are fixed by joining the front
housing head shell 10' and the rear housing head shell 11' via the
webs
located in the housing head shells 10', 11'. Furthermore, the
connection contacts 4' comprise a spring contact 7, by means of
which a mating contact--which is not shown--in the housing body 3
can be contacted such that these, as the electrical part of the
connection mechanism, can enable the electrical connection of the
connection contacts 4' to the ends of the secondary coil.
[0052] FIG. 4b shows the second embodiment of a housing head 2'
depicted in FIG. 4a, in the installed state. A groove 5, as part of
the mechanical connection mechanism, can be seen on the lower edge
of the housing head 2'.
[0053] FIG. 5 shows a current transformer 1 according to a
preferred embodiment of the invention having the housing body 3
depicted in FIG. 1 and the second embodiment of a housing head 2',
which is depicted in FIG. 4b. The spring 6, which can be seen in
FIG. 1, engages into the groove 5, which can be seen in FIG. 4b.
The mutually engaged groove-spring design is covered by the upper
edge of the housing body 3.
[0054] FIG. 6 shows a current transformer 1 according to another
embodiment of the invention with the short-circuiting device
21.
LIST OF REFERENCE SIGNS
TABLE-US-00001 [0055] current transformer 1 housing head 2, 2'
housing body 3 connection contact 4, 4' groove 5 spring 6 spring
contact 7 push-in contact 8 screw-type contact 9 front housing head
shell 10, 10' rear housing head shell 11, 11' protective
electronics or 20 functional electronic component short-circuiting
device 21
* * * * *