US2514012A - Current-limiting and protective arrangement - Google Patents

Description

July 4, 1950 A. B. RYPINSKI LIMITING AND PROTECTIVE ARRANGEMENT CURRENT- Filed D90. 29, 1945 PIC-1.4

FIG.

FIGB

Patented July 4, 1950 CURRENT-LIMITIN G AND PROTECTIVE ARRANGEMENT Albert B. Rypinski, Laurelton, N. Y., assignor to Della C. Rypinski, Laurelton, N. Y

Application December 29, 1945, Serial No. 638,068

11 Claims.

The invention herein disclosed relates to a current limiting and protective arrangement of the kind described in my copendin g application Serial No. 532,325, filed April 22, 1944, which issued as U. S Patent 2,436,334 on February 17, 1948, for Current-Limiting and Protective Arrangement.

In my said copending application for patent there is disclosed and described a winding comprising several inductively coupled coils and an electromagnetically actuated switch for changing the electrical relation of the coils to vary the impedance of the winding. The winding is arranged to provide two magnetic circuits, a main magnetic circuit and an auxiliary magnetic circuit in the end turns which auxiliary magnetic circuit acts upon the electromagnetically actuated switch. All of the coils of the Winding interlink both the main and auxiliary circuits.

An object of this invention is to provide a current-limiting and protecting arrangement of the kind mentioned in which at least one coil of the winding is interlinked with only one of the magnetic circuits. Another object of the inventon is to provide an arrangement of this kind in which at least one coil is interlinked with only one of the magnetic circuits and at least one coil interlinks more than one magnetic circuit. A further object of the invention is to provide such an arrangement in which one of two magnetic circuits has no movable parts and the other has a movable part which is influenced by a coil local to the magnetic circuit containing the movable part and a coil interlinking both magnetic circuits. Another object of the invention is to provide such an arrangement which has a reactor as one component and an electromagnet or electromagnetically actuated switch as another component, the end turns of the reactor extending to embrace the electromagnet and afiect the function thereof. A further object of the invention is to provide such an arrangement in which an electromagnetically actuated switch is in series with a circuit, a reactor is shunted across the switch, and end turns of the reactor extend to embrace the core of the electromagnetically actuated switch, the switch serving to break a circuit and the reactor serving the dual purpose of limiting the current in the series circuit and holding the switch in circuit-breaking position. An additional object of the invention is to provide such an arrangement having an electromagnetically actuated switch as one component, a transformer as a second component,

-ment embodying the invention;

Fig. 2 which is a transverse, sectional plan taken on the line 2-2 of Fig. 1:

Fig. 3 which is a sectional elevation showing the arrangement connected in circuit;

Fig. 4 which is a sectional plan of a dual unit mounted on a common core;

Fig. 5 which is a sectional plan of a modified form of the arrangement; and

Fig. 6 which is a sectional plan of two devices connected in a three phase circuit.

The specific arrangement disclosed in the drawing for the purpose of illustrating an embodiment of the invention, consists, in general, of a winding comprised of three coils. One of the coils is local to or interlinked with a particular magnetic circuit which may be termed the main magnetic circuit, and another of the coils is local to or interlinked with another particular circuit which may be termed the auxiliary magnetic circuit. A magnetically actuated switch device is associated with the auxiliary magnetic circuit. The third coil interlinks both magnetic circuits.

The main magnetic circuit consists of a core I. About one leg of the core i, two coils 2 and 4 are wound. The coil 4 is local to the magnetic circuit of the core I, but the coil 2 is extended to provide end turns that embrace a core des ignated generall by the numeral 3 upon which a coil 5 is wound. The core 3 desirably consists of a movable core 6 and a stationary core I which cooperate with a U-shaped loop 8 to complete a local magnetic circuit for the coil 5 and the end turns of the coil 2. The movable core 6 carries a contact piece 9 which, normally, connects spaced stationary contacts [0 and H. When the core 6 is lifted electromagnetically it carries with it the contact piece 9 and breaks a circuit between the contacts I U and I I. The core I may be a part of any well-known dash pot or other arrangement for imparting a time delay to the movement of the core 6. The details of this arrangement form no part of the present invention and therefore it will not be further described. The contacts 10 and Il may be connected in a variety of circuit arrangements, someof which are hereinafter described.

Coil 5 is local to the auxiliary magnetic circuit represented by the cores 8 and 1 and the U- shaped loop 8. The coil 2 interlinks the main magnetic circuit represented by the core I and the auxiliary magnetic circuit. The space l2 between the coils 4' and 5 may be of different amount to control any slight magnetic effect the coil 4 may have on the core of the auxiliary magnetic circuit,

One manner of interconnecting the arrangement above described in circuit to control the current flow from a supply to a load is illustrated in Fig. 3. The supply is represented by line wires l3 and I5 and the load is indicated at l4, there being the usual manual switch [6 to control current flow to the load. Coils 2 and 4 are connected in series and across the contacts l and II. This is efiected by a connector 2' connecting one end of coil 2 to the contact In, a connector 2" connecting the other end of the coil 2 to one end of the coil 4, and a connector 4 connecting the other end of coil 4 to the contact H.

The coil 5 is connected in series with the load through the switch contacts Ill and II and the movable contact 9. For this purpose, the'line I3 is connected to one end of the coil 5. The opposite end of the coil 5 is connected by a connector 5 to the contact III. A line H' connects the contact II to one side of the manually operative switch l6 and another line connects the other side of the switch l6 to one side of the load l4. The opposite side of the load I4 is connected directly to the line wire [5. Thus, current flowing to the load passes, when contacts l0 and II are bridged by the movable contact 9, through the coil 5 and the coils 2 and 4 are shunted.

When the current flow through the coil 5 becomes excessive, the magnetomotive force generated lifts the core 6. The circuit between contacts i0 and II is thus opened. Current flowing to the load must now pass through coils 2 and 4 which previously carried substantially no current. These coils now serve to limit the flow of current to a predetermined safe value. By reason of the end turns of coil 2, the auxiliary magnetic circuit' is maintained and suiiicient magnetomotive force generated to hold the core all of the following functions: (A) allow any current up to a predetermined maximum, 1. e., full rated load to pass with a minimum of loss or drop; (B) allow momentary overloads of values less than short circuit to pass without limitation; (C) on sustained overload, allow the overload to pass for a time period as long as is consistent with safety to the circuit apparatus, then limit the total current flow to an amount less than full rated load, or an amount to permit safety devices in the controlled circuit to function properly and in sequence; (D) limit the current instantly on short circuit to a value safe for the controlled circuit; (E) when an overload is removed restore full voltage to the controlled line; and (F) when a short circuit is removed, restore full voltage to the controlled line.- When contacts 9, l0 and II are closed, the arrangement functions in accordance with A, B and C above. The time delay in opening the switch 9, Ill and II takes care of momentary and sustained overloads for limited times. When contacts 9, l0 and H are opened by sufficient current in winding 5, which is of up and the switch open. When the current flow I is interrupted, as by opening the switch IE, or I the current demand falls to the predetermined value, which is insufllcient for the end turns of coil 2 to sustain the core 6, the core 8 drops and contacts Ill and It are again connected through contact 9. Full current may then flow, with switch l6 closed, to the load l4. If coil 4 be omitted, the arrangement will also serve to limit current flow to protect a circuit. With such an arrangement, the coil 2 and core l act as a reactor with extended end turns, and the coil 5 constitutes part of an electromagnetic switch. When coil 4 is included, the arrangement of coils 2 and 4 with core I constitutes a transformer with the end turns of one coil of the transformer extended to interlink and cooperate with the coil 5 in the operation of the electromagnetically actuated switch.

A control arrangement such as that described above and embodying this invention may be connected in a series circuit to perform any one or relatively few heavy turns, conditions C and D maintain, that is, sustained overloads of long duration and short circuits are taken care of. Finally conditions E and F are met when the load circuit is interrupted, allowing contacts 9, Ill and II to close instantly, or when the current is reduced to a. point at which coils 2 and 5 can no longer hold up core 6. The arrangement described above is capable of performin all the foregoing functions with a minimum of moving parts and a minimum amount of material. It is capable of construction into one compact unit.

While contacts 9, l0 and H are open, the circuit current may be of any order of value the coil designer desires. 'It may be very low, a, small fraction of an ampere, with either an overload or short circuit in the supplied line. It may be an amount less than full rated load on the circuit and thus permit limited current fiow to an overloaded line. This is of value, for example, for lighting circuits as the lights will burn at reduced value while the trouble is being located. Or the current flow may be set at values heavy enough to allow series fuses to blow in proper sequence or circuit breakers to open.

For a three wire, single phase, alternating current circuit, two, separate units similar to that of Fig. 1 may be employed, or they may be combined on a single core as shown in Fig. 4:. In the arrangement shown in Fig. 4, there is a closed core having end limbs H and I8 and a central limb ll. Each end limb is a part of a completed unit. The end limb ll carries a coil 2a with end turns about a coil 5a that is wound about a core 3a, the magnetic circuit of which is completed by a loop to. The end limb is carries a coil 2b with end turns about a coil 5b wound on a core 312, the magnetic circuit of which is completed by a loop 81;. The central limb ll carries the combined magnetism of the limbs ll and it but the net efiect is that the two units are completely independent of each other in operation.

Where it may be desired to have, in a dual unit, the magnetism set up by one coil and trip arrangement react on the other. the construction of Fig. 5 may be used. Here, the common core Ia. has end limbs l9 and 20 but no central limb. The coil 20, is wound about the limb is and the coil 2b is wound about the limb 20. Any magnetism flowing through one limb must pass through the other and thus the main magnetic circuit of the two represented by the core la is common to the diagrammatically,

I r coils 2a and 2b and the coils are interlinked. This is important where it is desired to have all line currents put under control in a polyphase line when one line is overloaded, as in a motor control.

In Fig. 6, the dual unit of Fig. 5 is shown, as connected into a three phase motor circuit. The supply is represented by three line wires 2|, 22 and 23 and the motor at 26. One of the units, designated generally by the numeral 24, is connected in the line 2|, the coil 5a being connected in series through the switch contact 9a, and the coil 2a being normally shunted by the switch contact 90. and placed in series upon the contact 9a moving away from the stationary contacts. The other unit, designated generally by the numeral 25, is connected in the line 23, the coil 52) being connected in series through the switch contact 9?) and the coil 2b being normally shunted by the switch contact 9b and placed in series with the load upon the contact 9b moving away from the stationary contacts.

If, for example, an overload flows into the leg 21 of the motor, unit 24 opens the switch 9a and limits the current in that phase. When this condition maintains, coil 2a is energized and magnetism flows through the core la. Current is thus induced in coil 2b constituting a closed loop on limb of, the core. This induced current when of sufiicient amount lifts the movable core of core 32) and opens the switch 92). When this occurs, the current flow through the two remaining phases is limited.

From the foregoing description of the embodiments of the invention illustrated in the drawing and described above, it will be apparent to those skilled in the art that the current-limiting and protective arrangement of this invention has many advantages. For example, where it is advantageous to have a single coil set up magnetism in both magnetic circuits the arrangement may be made to do so, and where it is advantageous at the same time to have another winding exert its full eiTect in one or the other magnetic circuit without effect on the remaining magnetic circuit, this may be done. This improved arrangement makes it possible for a coil embracing the main core to perform a single function in connection with that core, and a coil embracing both cores to perform a dual function, one in connection with the main core and another and different function in connection with the end turn core. The net result is to conserve winding space, decrease material required and raise the eiTi-ciency.

While the invention has been illustrated and described as applied to particular purposes and with particular arrangements of coils and parts, it will be obvious that those skilled in the art may alter the arrangements within the principle and scope of the invention as expressed in the appended claims.

I claim:

1. In a current-limiting and protective arrangement of the kind described the combination comprising a winding arranged to provide two magnetic circuits and including a coil interlinking only one of said magnetic circuits and another coil electrically connected to said first mentioned coil and interlinking both magnetic circuits.

2. A current limiting and protective arrangement of the kind described comprising in combination a winding arranged to provide two magnetic circuits and including a coil interlinking only one of said magnetic circuits and another coil electrically connected to said first mentioned coil and interlinking both magnetic circuits, and an electromagnetically actuated device arranged to be acted upon by the magnetism of the magnetic circuit interlinked by both coils.

3. A current limitingand protective arrangement of the kind described comprising in combination a winding arranged to provide two magnetic circuits and including a coil interlinking only one of said magnetic circuits and another coil interlinking both magnetic circuits, and an electromagnetically movable element arranged to be acted upon by the magnetism of the magnetic circuit interlinked by both said coils.

4. A current limiting and protective arrangement of the kind described comprising in combination a winding arranged to provide two magnetic circuits and including a coil interlinking only one of said magnetic circuits and another coil electrically connected to said first mentioned coil and interlinking both magnetic circuits, and an electromagnetically actuated switch arranged to be actuated by the magnetism of the magnetic circuit interlinked by both coils.

5. A current limiting and protective arrangement of the kind described comprising in combination a winding arranged to provide two magnetic circuits and including a coil interlinking only one of said magnetic circuits and another coil electrically connected to said first mentioned coil and interlinking both magnetic circuits, and an electromagnetically actuated switch arranged to be actuated by the magnetism of the magnetic circuit interlinked by both coils, and connections between the coils and the switch, whereby upon actuation of the switch the electrical relation of the coils is altered.

6. In a current-limiting and protective arrangement of the kind described the combination comprising a winding arranged to provide two magnetic circuits and including a coil local to one of the magnetic circuits, another coil local to the other magnetic circuit and a third coil common to both magnetic circuits, the several coils being electrically interconnected.

7. In a current-limiting and protective arrangement of the kind described the combination comprising two windings, each winding being arranged to provide two magnetic circuits and each winding having a coil local to one of the magnetic circuits and a coil electrically connected to said first mentioned coil and common to both magnetic circuits, said latter coils embracing a common core.

8. In a current-limiting and protective arrangement of the kind described the commbination comprising two windings, each winding being arranged to provide two magnetic circuits and each winding having a coil local to one of the magnetic circuits and a coil common to both magnetic circuits, said latter coils embracing a common core having two independent magnetic circuits, one for each of the coils.

9. In a current-limiting and protective arrangement of the kind described the combination comprising two windings, each winding being arranged to provide two magnetic circuits and each winding having a coil local to one of the two magnetic circuits and a coil common to both magnetic circuits, said latter coils interlinking a common magnetic circuit.

10. In a current limiting and protective arrangement of the kind described and adapted to be connected in series in a circuit, the combination comprising a winding arranged to provide two magnetic circuits and including two electrically connected coils, one of said coils interlinking only one of said magnetic circuits and the other of said coils interlinking both of the magnetic circuits.

11. In a current limiting and protective arrangement of the kind described and adapted to be connected in series in a circuit, the combination comprising a winding arranged to provide two magnetic circuits and including two coils, one of said coils interlinking only one of said magnetic circuits and the other of said coils interlinking both of the magnetic circuits, an electromagnetically actuated switch arranged to be actuated by the magnetism of the magnetic circuit interlinked by both said coils, and connections between the switch and the coils arranged such that in one position thereof the magnetic circuit interlinked by both coils is sub-' stantially unaffected by one of said coils and in the other position of the switch substantially unaifected by the other of said coils.

ALBERT B. RYPINSKI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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