Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS1569723 A
Publication typeGrant
Publication dateJan 12, 1926
Filing dateAug 14, 1925
Priority dateAug 14, 1925
Publication numberUS 1569723 A, US 1569723A, US-A-1569723, US1569723 A, US1569723A
InventorsDickinson Wilbur K
Original AssigneeGen Electric
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Instrument transformer
US 1569723 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Jan, 12 1926.

W. K. DICKINSON INSTRUMENT TRANSFORMER Filed August 14, 1925 m n e v .m

Wi lbur KDICKinSQI His Attorneg Patented J an. 12, 1926.



INSTRUMENT TRANSF RMERQ Application filed August 14, 1925. SeriaI'Nc. 50,327.

To all whom it may concern:

Be it known that I, WILBUR K. Dioxin-v soN, a citizen of the United States, residing at Lynn, in the county of Essex, State of Massachusetts, have invented certain new and useful. Improvements in Instrument Transformers, of which the following is a specification. v

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 s 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 ob ect of the invention to mount the core parts on their support so that their contacting surfaces may adjust themselves to an accurate fit when brought together. A further object of the invention is to mount the core parts on their support in such manner that the pressure between the contacting surfaces will be evenly distributed, thus further con-' tributing to low reluctance of the flux path and to a uniform distribution of the flux throughout the cross section of the path at the contacting surfaces between the two core parts.

Further objects and advantages will ap-.

ear from the following description taken in connection with the accompanying drawing in which Fig. 1 is a perspective view of an instrument transformer constructed in accordance with the invention, Fig. '2 is a side view of the transformer shown in Fig. 1. and Fig. 3 is a side View of a modified form of the invention, a section of the winding being broken away in Figs. 2 and 3 to reveal details of construction.

Like reference characters indicate similar parts in the different figures of the drawing.

In theform of the invention shown in Figs. 1 and 2 a closed substantially ring shaped core 10 is divided into two parts, thus forming two joints at opposite sides of the core. The contacting s'urlaces at these joints preferably lie in a single plane passing through the axis of the core. The

contacting surfaces at each joint are finished to fit together accurately. Each of the core parts comprises a stackof magnetic tended into the two spaces 13 inthe two parts of the core. The flattened end 16 of eachrhandle has an opening which fits the enlarged portion 12 of one'of the rivets 11 so that each core part is pivotally sup ported on the flattened end of the handle which carries it. The two-handles 14 are-crossed and pivoted together by a rivet 17 between the grips 15 and the flattened ends 16 so;

that the two parts of the core may be closed and pressed together by means ofthe grips 15. A clasp 18 may be used to hold the two core parts pressed tightly together while thetranformer is in use. A winding 19 is distributed in two parts over the two parts of the core and connected through a terminal box 20 with the outside leads 21.

A low reluctance path for-the magnetic flux in the core is desirable and for this .reason it is important that the contacting surfaces of the two core parts fit together accurately and it is also desirable that the pressure between the two core parts when closed together be distributed substantially equally-between the two joints. The surfaces ,at'the two core joints are accurately finished to make accurate contact when the.

two core parts are properly positioned together andlthe pivotal connections between the two core parts and the flattened ends 16 of the two handles permit proper relative adjustment of the two core parts -when pressedtogether by the handles. The particular rivet 11 which connects. each core part to its supportinug handle is preferably about midway between the two ends of the core part so that the pressure of the handle is disributed substantially equally between thetwo core joints.

v The construction shown in Fig. 3 is similar to that which has been described in connection with Figs. 1 and 2 except that the handles 14; are not crossed and are pivoted thereto.

The invention provides an efficient and convenient instrument transformer having a core which ma be easily opened and placed around a con uctor which cannot itself be conveniently opened. The pivotal connections between the core parts and their supporting handles permit these core parts to adjust themselves accurately together when pressed together by the handles and thus obviates the necessity of great accuracy in construction and compensates for wear in the pivotal connection between the two handles.

What I claim as new and. desire to secure by Letters Patent of the United States, is:

'a separable two part core and two pivotally connected handles supporting said core parts, one of'sad core parts being pivotally connected to its supporting handle.

21 An instrument transformer including a separabletwo part core, and two pivotally connected handles pivotally supporting said core parts.

3. An instrument transformer including'a separable two part laminated vcore, and two pivotally connected handles supporting said core parts, the lamination of one of said core parts being separated into two groups with a space therebetween, and one end of one of said handles extending into said space and being adjacent core part.

pivotally connected therein to the In witness whereof, I have hereunto set my hand this 11th day of August, 1925.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2431189 *Mar 28, 1946Nov 18, 1947Gen ElectricElectromagnetic induction apparatus
US2494206 *Apr 23, 1946Jan 10, 1950Ross Wayne MElectrical measuring instrument
US3250983 *Sep 29, 1964May 10, 1966Atkinson Duane EReactive pickup for vehicle control system
US3253215 *Sep 30, 1959May 24, 1966Automatic Switch CoOverload current detecting device having laminated split core means coupled to a holding circuit with indicator
US4048605 *Apr 5, 1976Sep 13, 1977Sangamo Electric CompanySplit core current transformer having an interleaved joint and hinge structure
US4839600 *Mar 17, 1987Jun 13, 1989Kuurstra John CAmmeter for use with A.C. electric power lines
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
US9146264Jan 12, 2012Sep 29, 2015Veris Industries, LlcCurrent meter with on board memory
US20060006976 *Oct 18, 2004Jan 12, 2006Veris Industries, LlcSplit core sensing transformer
DE976371C *Nov 17, 1954Jul 25, 1963Licentia GmbhAnlegestromwandler
DE976495C *Oct 24, 1952Oct 3, 1963Friedrich Dr-Ing E H RaupachTragbarer, als Zange ausgebildeter Einleiterstromwandler
U.S. Classification336/66, 336/212, 336/176, 336/174
International ClassificationH01F38/30, H01F38/28
Cooperative ClassificationH01F38/30
European ClassificationH01F38/30