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Publication numberUS1830541 A
Publication typeGrant
Publication dateNov 3, 1931
Filing dateJun 20, 1930
Priority dateJun 20, 1930
Publication numberUS 1830541 A, US 1830541A, US-A-1830541, US1830541 A, US1830541A
InventorsHarris Hiram E
Original AssigneeGen Electric
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Instrument transformer
US 1830541 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Nov, 3, 1931; H. E. HARRIS INSTRUMENT TRANSFORI BR Filed June 20. 1930 I Inventofi H'ITGJTI Eli Harris,

I His Attcrney.

il atented Nov. f5, 3193?.



My invention relates to instrument transformers of the type in which a winding is mounted on a core which is separable to permit it to be opened and placed around a current carrying conductor. Such a transformer may be used for a variety of purposes but is commonly used in connection with an ammeter for measuring the current in the conductor which it surrounds. It is desirable that the contacting surfaces of the two-part core fit together accurately so that the reluctance of the flux path through the core may be low and it is the general object of the invention to provide an improved support for the two core parts so arranged that the contacting surfaces of the core parts may fit accurately when brought together.

The invention will be better understood from the following description taken in connection with the accompanying drawings 'in which Fig. 1 is a view of an instrument transformer constructed in accordance with the invention; Fig. 2 is a view of the two parts of the core shown in Fig. 1, and Fig. 3 is a perspective view of 'one of the core parts.

Like reference characters indicate similar parts in the different fi ures of the drawin s.

The transformer w ich is shown in t e drawings as illustrative of the invention includes a ring shaped magnetic core divided into two separable parts 10 and 11 by two joints at opposite sides of the core. The contacting surfaces at these joints preferably lie in a single plane passing through the axis of the core and the surfaces at each joint are finished to fit together accurately. Each of the core parts 10 and 11 is formed of a stack of magnetic laminations secured between a pair of supporting end plates 12 by rivets. The two core parts 10 and 11 are pivoted together near one of their joints by a bolt 13 extending through openings 14 in.

extensions 15 formed integrally with the end plates 12. The other ends of the end plates 12 are also provided with integral extensions 16 and a latch 17 to hold the core parts closed together about a current carrying conductor. A secondary winding 18 is formed in two sections which surround the two core parts 10 and 11 respectively and is connected to 1930. Serial No. 462,681.

terminals 19 by a flexible two conductor cord 20. A strap 21 is attached to the extensions l5 of the end plates 12 for convenience in carrying the transformer.

A low reluctance path for the magnetic flux in the core is desirable and this makes it important that the contacting surfaces at each core joint be accurately fitted and that they be pressed tightly together when the core is held closed by the latch 17 The openings 14 in at least one pair of the extensions 15 of the end plates 12 are enlarged or elongated so as to fit loosely on the pivot bolt 13 and thus the two core parts 10' and 11 are pivoted loosely together. The loose fit in this pivotal connection assures that both core joints may be closed tightly. The latch 17 holds the core joint nearest this latch tightly closed. The other core joint is held tightly closed by a tension spring 22 connected by bolts 23 between the extensions 15 of the end plates 12 of the two core parts. A stop 24 pivoted to one core part and having a slot engaging a pin on the other core part may be provided to limit the extent to which the core may be opened.

The invention provides an instrument transformer with a core having two separable pivotally connected parts which may be held tightly together without the necessity for accuraite workmanship in the pivotal joint. There is also the advantagethat any wear in the pivotal connection between the core parts cannot affect the closing of the core and the tightness of its joints when closed.

The invention has been explained by describing and illustrating a particular form thereof but it will be obvious that changes may be made without departing from the spirit of the invention or the scope of the 2. An instrument transfo v separable two part core W1" mo jGIH-ES,

two parts of the core being looseiy pivoted together near one of said joints, and. a tension spring connected between the ends of said core parts nearest said pivotai connection to close the adiacent joint tightly when the other joint is closed.

3. An instrument transformer including a ring shaped core divided into two sepumne parts by two joints, said two parts of the core being loosely pivoted together near one of said 10ints, a tension spring connected between the ends of said core parts nearest said pivotal connection to close the adjacent joint tightl when the other joint dosed, and means or holding said other joint tigi'nt- 1y closed. V

In witness whereof, I have hereunto set my hand this seventeenth day of Jame 1930.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2431189 *Mar 28, 1946Nov 18, 1947Gen ElectricElectromagnetic induction apparatus
US2447366 *Sep 1, 1943Aug 17, 1948Bendix Aviat CorpCoil and mounting therefor
US2452901 *Aug 16, 1944Nov 2, 1948Gen ElectricElectromagnetic induction apparatus
US2494206 *Apr 23, 1946Jan 10, 1950Ross Wayne MElectrical measuring instrument
US2677078 *Sep 30, 1947Apr 27, 1954Bendix Aviat CorpElectrical apparatus
US2779927 *May 20, 1952Jan 29, 1957Gen Electric Co LtdA. c. electrical measuring instruments
US2789268 *Sep 27, 1955Apr 16, 1957Baltimore Gas And Electric ComMethod and apparatus for identifying electric conductors
US3253215 *Sep 30, 1959May 24, 1966Automatic Switch CoOverload current detecting device having laminated split core means coupled to a holding circuit with indicator
US3725832 *Oct 12, 1971Apr 3, 1973Schwertzer E Mfg Co IncMagnetic core structure
US4048605 *Apr 5, 1976Sep 13, 1977Sangamo Electric CompanySplit core current transformer having an interleaved joint and hinge structure
US4983932 *Sep 22, 1989Jan 8, 1991Kitagawa Industries Co., Ltd.Electric noise absorber
US6144277 *Jul 2, 1993Nov 7, 2000Matsui; KazuhiroElectric noise absorber
US7312686 *Oct 18, 2004Dec 25, 2007Veris Industries, LlcSplit core sensing transformer
US7855655Aug 13, 2008Dec 21, 2010Veris Industries, LlcCurrent switch with automatic calibration
US7902992Aug 13, 2008Mar 8, 2011Veris Industries, LlcStatus indicator
US8212548Jun 2, 2009Jul 3, 2012Veris Industries, LlcBranch meter with configurable sensor strip arrangement
US8421443Nov 20, 2009Apr 16, 2013Veris Industries, LlcBranch current monitor with calibration
US8421639Nov 20, 2009Apr 16, 2013Veris Industries, LlcBranch current monitor with an alarm
US8692540Aug 13, 2008Apr 8, 2014Veris Industries, LlcSplit core status indicator
US20060006976 *Oct 18, 2004Jan 12, 2006Veris Industries, LlcSplit core sensing transformer
DE976371C *Nov 17, 1954Jul 25, 1963Licentia GmbhAnlegestromwandler
EP0961124A2 *May 26, 1999Dec 1, 1999Matsushita Electric Industrial Co., Ltd.Multicircuit type instrument and split type current transformer for measuring various electric power quantities
U.S. Classification336/176, 336/66, 336/210, 336/174, 310/216.33, 310/216.23
International ClassificationH01F38/28, H01F38/30
Cooperative ClassificationH01F38/30
European ClassificationH01F38/30