US2595869A - Phase modifier - Google Patents

Description

y 6, 1952 s. MlNNECl 2,595,869

PHASE MODIFIER Filed May 15, 1951 Inventor: Salvatore Minneci,

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Patented May 6, 1952 PHASE MODIFIER Salvatore Minneci, Pittsfield, Mass., assignor to General Electric Company, a corporation of New York Application May 15, 1951, Serial No. 226,428

2 Claims.

This invention relates to phase modifiers and, more particularly, to improvements in adjustable phase modifiers of the non-rotating type.

It is frequently desirable to introduce variable amounts of phase modifying leading and lagging reactive volt-amperes into an electric circuit, such, for example, as a commercial frequency power transmission, or distribution circuit. In accordance with this invention, there is provided a novel phase modifier for accomplishing this purpose which is characterized by utilizing substantially the entire tap range of a transformer winding twice for successively controlling the amount of leading and lagging reactive volt-amperes in such a way that a tap changing mechanism operating over its entire tap range varies the leading reactive volt-amperes between minimum and maximum values in one part of the over-all range of operation of the device, and the same tap changing mechanism at another time'operating over its entire tap range varies the lagging reactive volt-amperes between maximum and minimum values in the other part of the over-all operating range of the device.

An object of the invention is to provide a simple and economical phase-modifier for selectively and non-simultaneously controlling variable amounts of leading and lagging reactive volt-amperes between maximum and minimum values.

The invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the single figure of the accompanying drawing, which illustrates diagrammatically an embodiment of the invention, there is a main alternating current circuit I, the phase of the current of which is modified by the phase modifier indicated generally at 2. Phase modifier 2 comprises a multi-tapped transformer 3, of any well known type, which is illustrated by way of example as a two-winding insulating transformer having a primary winding 4 connected across the main circuit I and a multi-tapped secondary winding '5. The taps for the winding 5 comprise a pair of spaced taps 6 and I which may be located anywhere on the winding, and which may be end taps or terminals, as illustrated. Between taps E and I are a plurality of electrically, equally-spaced intermediate taps of any desired number, eight being shown, and identified, respectively, as 8, 9, III, II, I2, I3, I4, and I5. For making selective connection with these taps, there is provided a rotary tap changing switch 2 of the dial type which is provided with a plurality of fixed contacts arranged in a circle, and a cooperative movable contact assembly for making selective connection to or engagement with fixed contacts. In the preferred form of dial switch, as illustrated, there is one more fixed contact than there are intermediate taps. Thus, the tap changing switch is provided with fixed contacts 8', 9', III, II, I2, I3, I4, and I5, connected respectively, and in corresponding sequence, with the like-numbered intermediate taps, and there is an extra or additional fixed contact I6 which is placed between the contacts 8' and I5 which are connected respectively to the intermediate taps 8 and I5 which are respectively adjacent the spaced or end tap 6 and I. The movable contact assembly is indicated at I! as comprising a pair of spaced contact fingers I8 and I9, which are interconnected by a, midtap impedor 20 for permitting tap changing operations without breaking the transformer secondary circuit, and for providing intermediate operating steps when the respective contact fingers engage adjacent fixed contacts, so as to place the impedor 20 in a bridging relation with respect to those fixed contacts. The leading reactive volt-amperes produced by the phase modifier are provided by a capacitive reactor (capacitor) 2| connected to top 6, and the lagging volt-amperes produced by the phase modifier are provided by an inductive reactor (inductor) 22 connected to the tap I.

For transferring the connections of the capacitor 2| and the inductive reactor 22 to and from the secondary winding 5 by way of the tap changer switch, there is provided a two-position transfer switch having a common terminal 23 and a pair of main terminals 24 and 25 connected respectively to the inductive reactor 22 and the capacitor 2|. This transfer switch may be of any suitable type, such as the simple singlepole double-throw switch illustrated.

The transfer switch is driven from the movable contact assembly I'! of the tap changing switch by an intermittent drive mechanism, such as a Geneva gear mechanism 26, which is so arranged that the transfer switch is moved from one of its circuit closing positions to the other when the movable contact assembly I1, in the middle of its range of motion, is moving between fixed contacts 8' and I5, or, more particularly, when it is moving across the extra fixed contact I 6, which is between the fixed contacts 8 and I5.

The extra fixed contact I6 and the movable contact I! are directly connected to a conductor 3 21 which connects them to the common terminal 23 of the transfer switch.

The operation of the illustrated embodiment of the invention is as follows: The parts are shown in the position for providing maximum lagging volt-amperes for the circuit I, in that the inductive reactor 22 is connected between taps I and 8 so as to have applied to it practically the entire voltage of the secondary winding 5.

If, now, the movable contact assembly I! is rotated clockwise, as viewed in the drawing, the voltage applied to the inductive reactor 22 is progressively decreased until when the movable contact assembly I! breaks engagement with the fixed contact I5, there will be zero voltage applied to the inductive reactor 22 and, hence, there will be zero lagging volt-amperes provided by the phase modifier for the circuit I. Continued clockwise motion of the movable contact assembly I! will now cause the Geneva gear mechanism 26 to operate the transfer switch from its illustrated position to its other circuit closing position in which terminals 23 and 25 are interconnected, and this operation will .be completed by the time the movable contact assembly I! first contacts the fixed contact 8' of the tap changing switch. As soon as such contact is established, minimum finite voltage will be applied to the capacitor 2| so as to provide minimum leading volt-amperes for phase modification of circuit l. Continued clockwise rotation of the movable contact assembly I! will progressively increase the Voltage applied to the capacitor 2|, thus progressively increasing the leading volt-amperes pro vided by the phase modifier, until the equipment reaches the other end of its range of operation in which contact assembly I! engages fixed contact While I have shown a particular embodiment of my invention, it will be understood that I do not wish to be limited thereto, since many modifications may be made; and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

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

1. In combination, a transformer winding provided with a pair of spaced taps between which there are a plurality of spaced intermediate taps,

a conductor, a rotary tap changing switch for selectively connecting said conductor to said intermediate taps in regular sequence except that said switch has a pair of adjacent positions in which it connects said conductor to intermediate taps which are respectively electrically nearest said spaced taps, a capacitor, an inductor, a transfer switch for selectively connecting said conductor to said spaced taps through said capacitor and inductor respectively, and an intermittent mechanical drive for said transfer switch from said rotary tap changing switch for operating said transfer switch only when said rotary tap changing switch is moving between its said pair of adjacent positions.

2. In combination, a transformer having a primary winding and a secondary winding, said secondary winding having a pair of end taps and N electrically equally spaced intermediate taps, a dial type tap changing switch comprising N plus one fixed contacts equally spaced around a circle and a movable contact pivotally mounted at the center of said circle for selective engagement with said fixed contacts, a two-position transfer switch having a common terminal and two main terminals which are respectively connected to said common terminal when said switch is in different positions, means for making a direct electrical connection between one of said fixed contacts, said movable contact and said common terminal, means for connectirv in sequence each remaining fixed contact to a different intermediate tap, an inductor connected between one end tap of said secondary winding and one main terminal of said transfer switch, a capacitor connected between the other end tap of said secondary winding and the other main terminal of said transfer switch, means including a Geneva gear mechanism interconnecting said movable contact and said transfer switch for causing said transfer switch to move from one position to the other when said movable contact is moving across said one fixed contact, and means including a midtapped impedor for preventing said movable contact from disengaging any fixed contact until it engages an adjacent fixed contact.

SALVATORE MINNECI.

No references cited.

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