US2572481A - Telemetric system - Google Patents

Description

Oct. 23, 1951 HQRNFECK 2,572,481

TELEMETRIC SYSTEM Original Filed 001:. 25, 1947 Z2 W6 57 i i 58 5 5 6| 6? it; 74 75 jl PHASE 78 I7 SENSITIVE RELAY m J l8 INVENTOR.

ANTHONY Jv HORNFECK transmitting and receiving mechanisms.

Patented Oct. 23, 1951 TELEMETRIC SYSTEIH Anthony J. Hornieck, Lyndhurst, Ohio, assignor to Bailey Meter Company, a corporation oi Delaware Original application October 25. 1947, Serial No.

782,114, now Patent No. 2,524,665, dated October 3, 1950. Divided and this application April 22, 1950, Serial No. 157,555

7 Claims.

This invention relates to telemetric systems, and more particularly to systems for transmitting signals in response to a variable and positioning a receivin member by the signals at a remote point to provide an indication or record of the variable.

A preferred form of my invention may include a transmitting mechanism operating to produce a signal varying in response to a variable to be measured, and a receiving mechanism having a balanceable network which is subjected to difl'erent unbalancing conditions during intervals of time varying with the signals transmitted. The signal may be transmitted during portions of fixed time intervals to produce a condition tending to unbalance the network in one direction, and means may be provided to produce another condition tending to unbalance the network in the opposite direction during the remainder of the time intervals. If desired, the transmitter may produce different signals during the portions of the time intervals for creating difl'erent unbalancing conditions. The unbalancing efl'ect on the network is proportional to the difl'erence between the products of the unbalancing conditions and the intervals of time during which each is applied. Means responsive to an unbalance oi the network may be provided for rebalancing the latter and for positioning suitable indicating or recording means.

An object of my invention is to provide an improved telemetric system. Another object is to provide a telemetric system having improved Yet another object is to provide a telemetric system which includes only a pair of wires between a transmitter and a receiver, and which operates to provide an indication or record at the receiver -oi' a variable by the transmission of signals at low voltage over the pair of wires. Other ob- ,iects will appear in the course of the following description.

The single figure of the drawing is a schematic diagram of an improved transmitting mechanism adapted for use in a telemetering system of the general type disclosed in my parent Patent No. 2,524,665 of which this application is a division.

The transmitter includes transformers 55 and 56 having primary windings 51 and 58 connected to a source of alternating current, and airing secondary windings 60, ti and 62, 53 connected in a closed loop by conductors 64, 65. A core member 61 is arranged between the primary and secondary windings of the transformer 55 and is connected to one end of a pivoted member I which engages at its other end with a cam ll rotated at a constant speed by a motor Ill. The cam 59 is shaped so as to reciprocate the core member 61 at a constant speed between the windings of the transformer. Arranged between the primary and secondary windings oi the transformer 56 is a core member I! which is connected to a device 73. such as a Bourdon tube. responsive to some variable condition. Leading from the closed loop at points between the aiding secondary windings are conductors 14 and I5 con nected to a phase sensitive relay 16 like that disclosed in my application, 8. N. 633,891, iiled December 8, 1945. This relay is of the electronic type and is operative at a very small voltage of a predetermined phase to move a contactor 18 into engagement with a contact 19 for completing the circuit through the conductors I1 and II. The core member 12 may be considered as a transmitting member since the closing of contactor 18 to energize the conductors ll, It is determined by the position assumed by this member.

When the core members 81 and I2 are in the same positions with respect to the windings of their transformers. the voltages induced in the corresponding secondary windings are equal and opposite so that the voltage across the conductors l4, I5 is zero. 11' the core members are displaced irom each other in one direction. a voltage of a certain phase exists across the conductnrs ll, 15, and the value of the voltage varies with the amount of displacement. When the core members are displaced in the opposite direction, a voltage opposite in phase to the first voltage exists across the conductors ll, 15. The range of reciprocation oi the core member 51 should be adjusted so that its upper and lower limits are equal to or greater than the limits of the core member I2 on maximum changs in the condition to be measured. The range or the core member 51 may be determined by the size of the cam 55 and the location of the pivotal support for the member 6..

Assume that the core members are in the same positions with respect to the windings of their transformers and that the core member 12 re- 7 mains in this position while the core member 61 is reciprocated. A very slight movement of the core member in one direction will produce a voltage of. a phase which operates the relay 18 to close the contactor 15 with the contact 15. While the core member moves in this direction to the end of its stroke and then returns to its initial position, the voltase will continueto be of a phase to operate the relay. As soon as the core member returns to its initial position the voltage across conductors 14, 15 becomes zero and the contactor 18 moves to its open position. A movement of the core member to the other side of its initial position results in a voltage opposite in phase to the first voltage, and the contactor I8 remains in its open position. If the core member 12 is in a position mid-way between the positions it would assume at the opposite limits of the condition measured, and if the core member 61 is reciprocated between corresponding limiting positions, the distances traveled by the core member 61 at opposite sides of the core I2 are equal and result in a holding of the contactor 18 open and closed equal intervals of time. A movement of the core member 12 from its mid-position means that the core member 61 must move an equal amount from such position to reach a point from which it may travel in either direction to produce voltages of diflerent phase. Since the core member 61 will have a greater distance to travel in one direction than the other from its new position, the contactor 18 will be held open or c os d longer intervals of time.

Whil there is disc osed in this application one form which my invention may assume in practice it will be understood that it may be modified and embodied in various other forms without departing from its spirit or the scope of the appended cla ms.

This application is a division of my copending application S. N. 782.114, filed October 25. 1947, now Patent 2.524.665 dated October 3, 1950.

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

1. A mechanism for transmitting signals representative of a variable condition including in combination. a closed loop circuit including two pairs of secondary transformer'windings, an energized primary winding for each pair of secondary windings, means for increasing the flux linkage between each primary and a secondary of each pair and to decrease the flux linkage with the other secondary of each pair to produce a net differential voltage across the two secondaries of each pair whose magnitude is a linear function of the movement of the flux linkage means, means for uniformly varying the linkage between one set of primary and secondary windings within predetermined limits, means for varying the linkage between the other set of primary and secondary windings in response to changes in the variable to be measured, a phase sensitive device connected to said closed loop at points between the two secondary windings of each included pair, and a circuit connected to a source of power and having a contactor controlled by said phase sensitive device.

2. A mechanism for transmitting signals representative of a variable condition including in combination, two transformers each having a primary winding and a pair of aiding secondary windings, means for energizing said primary windngs, means for connectng said secondary windings in a closed loop, means for variably flux-coupling the pri mary and secondary windings of each of said transformers, means for uniformly varying the coupling between one set of primary and secondary windings within predetermined limits, means for varying the flux-coupling between the other set of primary and secondary windings in response to changes in the variable to be measured, a relay sensitive to the difference in output connected between the secondary windings of each of said transformers, and a circuit controlled by said re ay.

3. A mechanism for transmitting signals representative of a variable condition including in combination, two transformers each having a primary winding and a pair of aiding secondary windings, means for energizing said primary windings, means for connecting said secondary windings in a closed loop, a core member movable between the primary and secondary windings of each of said transformers, means for reciprocating one of said core members in a predetermined path, means for positioning the other of said core members in response to changes in a variable to be mea ured. a phase sensitive device connected to said losed loop at points between the two secondary windings of each of said transformers, and a circuit connected to a source of power and having a contactor controlled by said device.

4. A mechanism for transmitting signals representative of a variable condition comprising, in combination, two transformers, each having a primary winding and a pair of aiding secondary windings, means for connecting said primary windings to a source of alternating current, means for connecting said secondary windings in a closed loop, core members movable between the primary and secondary windings of said transformers, means for positioning one of said core members in response to a variable to be measured, means for reciprocating the other of said core members between points corresponding to the positions assumed by the first core member at extreme values of said variable, a. phase sensitive device connected to said closed loop at diametrically opposite points, and a circuit connected to a source of power and having a contactor movable to open and closed positions under the control of said device.

5. A mechanism for transmitting signals representative of a variable condition comprising, in combination, two transformers, each having a, primary winding and a pair of aiding secondary windings, means for energizing said primary windings, means for connecting said secondary windings in a closed loop, core members movable between the primary and secondary windings of said transformers, means for reciprocating one of said core members in a predetermined path, means for positioning the other of said members in response to a variable to be measured, a phase sensitive relay connected to said closed loop at points between the secondary windings of each of said transformers, and a circuit connected to a source of power and having a contactor movable to open and closed positions under the control of said relay.

6. A mechanism for transmitting signals representative of a variable condition including in combination, two transformers each having a primary winding and a pair of aiding secondary windings, means for energizing said primary windings, means for connecting said secondary windings in a closed loop, core members movable between the primary and secondary windings, a cam operatively connected to one of said core members to move it in a predetermined path, a constant speed motor means for activating said cam uniformly that the core will reciprocate in the path, means for positioning the other of said members in response to a variable to be measured, a phase sensitive relay connected tosaid closed loop at points between the secondary windings of each of said transformers, and a circuit connected to a source or power having a contactor 8 movable to open and closed positions under the control or said relay.

7. A telemetric transmitter for transmitting an electrical signal varying in representation of a variable to be measured or transmitted, including in combination, two movable core transformers each having a primary winding and a pair of secondary windings and a core movable relative to the said windings for varying the flux linkage therebetween. a loop circuit including said secondary windings, a source of alternating current for the primaries, means for cyclically positioning the core of one transformer between predetermined limits, means for positioning the core of the other transformer in accordance with the variable, a phase sensitive device connecting the joining point of each pair of secondaries in said loop circuit, and a relay controlled by the said device.

ANTHONY J. HORNFECK.

No references cited.

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