US 5,633,580 AGranted

Direct load current sensing for predicted regulator tap position

AssigneeSiemens Energy & Automation, Inc.

InventorsJohn J. Trainor, Carl J. Laplace, William M. Thorsen, Jr.

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Abstract

A tap changer including a tap positionable to vary the winding ratio of the transformer in response to changes in an electric load on the transformer is disclosed herein. The transformer includes an electric drive which is responsive to raise or lower signals applied thereto in order to selectively position the tap by the raising or lowering of the tap and thereby raising or lowering the transformer winding ratio. Upon sensing the current of the motor control signals, an up/down counter is incremented or decremented. Accordingly, when a tap change signal is detected, the direction of tap changer movement may be determined, based upon the value of the up/down counter. In this way the tap position is also accurately determined and known.

Claims6

Dependent claims

A transformer having a selectable winding ratio comprising:

a plurality of windings including a tap assembly which is positionable to incrementally change the winding ratio of the transformer;
an electric drive mechanically coupled to the tap assembly to selectively and incrementally position the tap assembly to effect incremental changes of the winding ratio, said electric drive producing a direction signal which is related to movement of said electric drive;
an up/down counter adapted to receive said direction signal, said up/down counter incrementing and decrementing respectively with respect to said direction signal;
a count signal generator coupled to the tap assembly for generating a count signal in response to a tap change;
and
a digital processing circuit coupled to said up/down counter and said count signal generator, such that upon detecting a count signal from said count signal generator, said processor determines the direction of the tap change according to the value in said up/down counter when said count signal occurs, said processor thereby determining a new tap position.

3 more elements

Dependencies are inferred from the claim text.