US2241973A

US2241973A - Electroresponsive device

Info

Publication number: US2241973A
Application number: US335424A
Authority: US
Inventors: Aigner Viktor; Nerlich Bernhard
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1939-03-06
Filing date: 1940-05-15
Publication date: 1941-05-13
Anticipated expiration: 1958-05-13

Description

May 13, 1941.

V. AIGNER ET AL ELECTRORESPONSIVE DEVICE Filed May 15, 1940 Fig. I.

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VVVVV! lrwver-sbofs I Viktor` Aigner, Bernhard Nerlich,

b9 JV JM Patented` May 13, 1941 ELECTBOEESPONSIVE DEVICE Viktor Aigner, Steglitz, and Bernhard Nerlich,

Berlin -Charlottenburg, Germany, assign orato General Electric Company, a corporation of New York Application May 15, 1940, Serial No. 335,424 In Germany March 6. 1939 (Cl. F15-294) 12 Claims.

Our invention relates to improvements in electro-responsive devices which operate only at or near a predetermined point oi the wave of an alternating electric quantity and more particularly to such devices ior the control oi switches conducting alternating current whereby to eil'ect circuit interruption at or near the zero point of the current wave.

It is well known that. in order to minimize the destructive effect on contacts in the circuit-opening operation oi switches in heavy current or high voltage alternating current systems. it is desirable to eect the interrupting operation at the zero point oi the current wave. This requirement is particularly exacting when such switches are used for the remote control oi groups oi' similar consumers by opening operations in a predetermined time sequence for electing certain switching orders. Buch keying switches. as they are sometimes called. have, dependent on the number oi' the switching orders, to perform a large number of switching operations."y Consequently, the lite or such switches can be greatly increased ii the circuit interruptions can be eiiected at the zero point of the current wave. In such a case the wear on the contacts becomes theoretically zero and practically very small. Fluthermore, when the switches are opened for the purpose of removing faults. such as short-circuits, between conductors or between a conductor and ground,A the switch opening operation is facilitated and the wear on the contacts reduced if the interruption is eilected at the zero point oi' the current wave. The time between the releasing or tripping impulse for the switch and thev actual interruption may be an integral multiple of a haiil wave. Thus, i'or example, in pressure-operated switches. it is possible to keep the pressure substantially constant by the use oi sumciently large compressed air storage tanks. The problem then is, inthesecases,togive thereleasingortripping impulse at or near the zero point oi the current wave.

In accordance with our invention, we provide an improved electro-responsive device whose moi operation can be deinitely and closely controlled at or near a predetermined point oi an alternating electric quantity. Another object of our invention is to provide an improved arrangement ior eiecting the opening oi switches. conducting alternating current and having a substantially deinite opening time, only at or near the loro point oi the alternating current wave. These and other objects oi our invention will appear in more detail hereinafter.

Our invention will be better understood from the following description when considered in connection with the accompanying drawing. and its scope will be pointed out in the appended claims.

In the accompanying drawing, Fig. 1 illustrates diagrammaticaily an embodiment or our invention, and Fig. 2 is a curve diagram explanatory of the embodiment o! our invention shown in Pig. 1.

In the embodiment of our invention shown in Fig. l, an alternating current circuit l. shown in single line diagram for simplicity, is provided with a suitable circuit interrupting witch which is illustrated simply as a circuit breaker I of the latched closed type. Tine tripping or releasing impulse may be eiiected by a trip coil l to cause the opening oi the circuit breaker for keying purposes, the interruption oi' short-circuits, or otherwise.

In order to eilect the tripping or releasing impulse at the zero point of the current wave, we provide, in accordance with our invention, an electro-responsive device comprising a movable armature t, which may be pivoted as at 1, and two magnetic circuits including cores l and 0 i'or controlling the movement of the armature. In accordance with our invention, one oi' the magnetic circuits l is energized in accordance with an alterna-ting ciment derived from the circuit I by suitable means, such as a current transformer II, connected in this circuit and to the magnetizing winding Ii on the core l. Further. in accordance `with our invention, the other magnetic circuit I is energized at the desired time in accordance with a direct current which is dependent on the current in the circuit l and which may be obtained from a full wave rectiiler i2 connected to the magnetixing winding Il on the core l. The armature 6 is under the bias of a spring I4 which tends to urge the amature away from the poles of the magnetic core l against a stop Il'. The load circuit oi' the rectifier I2 may be provided with a smoothing condenser Ii, as shown. The movement of the armature t is arranged to control circuit-closing contacts II and I1. The closing oi contact II may energize the trip coli 5 directly 'or through the contacts of an auxiliary relay connected to the'source II. 'I'he closing of the contacts i1 eliminates the eiIect oi' the coil Il on the armature I as long as these contacts remain closed since they are arranged to short' the coil II.

exert any attractive eiiort on the amature. As shown, this means comprises contacts 2l normally closed by a movable contact-controlling member 2| which may be actuated either manually or otherwise, as, for example, by electromagnetic means examples of which are well known to the art. As shown, the contacts 20 are arranged in a circuit connected across the rectifier I2 so that, when these contacts are closed, the rectiner is short-circuited and no current is supplied to the magnetizing winding I3. When the circuit breaker I is open, the spring I I, as heretofore mentioned, urges the armature 6 away from the poles of the core 9. If, however, the circuit breaker l is closed and current is ilowlng in the circuit I, a corresponding secondary current appears in the current transformer I which, iiowing by way of the closed contacts 20, energizes the winding I I, thus tending to attract the armature I upwards to the poles of .the core 8.

When a releasing impulse or tripping action is to be given, the contacts 20 are openind by moving the circuit-controlling member 2l upwards. Under these conditions, current ows from the secondary side of the current transformer III through the rectifier I2 and, therefore, as direct current in the direction of the arrow 22 through the coil I3 but, as alternating current, through The condenser I5 smooths the rectined current to such an extent that a current, corresponding to the curve b in Fig. 2, flows in the coil Il. Through the coil Il, however, there is flowing an alternating current according to the curve a of Fig. 2. y

In accordance with our invention, the winding ratio of the two coils II and Il is so dimensioned that the ilux due to the direct current b is equal to the ilux due to the alternating current a at the desired predetermined distance or current value c of the straight line I-I from the abscissa axis O O. When the alternating ilux decreases below that due to the current value c, the direct ilux and, therefore, its magnetomotive force preponderates and this continues during the time z. When this condition occurs at a time after the release impulse is given by the opening of the contacts 20, the armature 6 moves downward and closes its contacts I6 and I1. The closing of the contact I1 short-circuits the winding Il so that the armature 8 remains in the downward contact closed position until after the disappearance of current in the circuit 3 by reason of the opening of the circuit breaker I whereupon the spring Il restores the armature to the unattracted position.

Since currents, which are in a xed relation to each other flow through the coils II and I3, the time interval u between the instant at which the direct current preponderates and the zero point of the alternating ilux is constant and independent of the magnitude of the current in the circuit l prevailing at the time. If the straight line I-I is placed at half the current amplitude, this means that the direct current ampere turns correspond to half the value of the maximum alternating current ampere turns. Then the distance u corresponds to an angle of 30 degrees independently of the peak value of the alternating current prevailing at the time.

Accordingly, 'the armature 6 is always actuated downwardly at a predetermined point of the current wave and closes the release contact I6. Since the opening time of the switch 4 can be adjusted to a desired value, the interruption takes place at or near the zero point of the current wave.

The curve diagram in Fig. 2 shows the built up or steady state condition of the currents and fluxes in the magnetic circuits l and I after the opening of the contacts 2l. In order to avoid any possibility of false operation during the gradual increase oi' the direct current to its steadyr state value, we provide means for preventing movement of the armature under the effect of the magnetic circuit 8. As shown, this means mechanically locks the armature against downward movement and comprises a latch 2l under the control of an electromagnetic device 24 which may be energized from a source 2l through contacts 2l under the control of the movable circuit-controlling member 2l. Thus, when the movable circuit-controlling member 2l is movedl upward to give the tripping or release impulse, it also energizes the electromagnetic device 24 which preferably has a suitable time delay suiilcient to insure the release oi' the latch only after the direct current in the coil Il has reached a steady state value.

While we have shown and described our inventioniin considerable detail, we do not desire to be limited to the exact arrangements shown, but seek to cover in the appended claims all those modifications that fall within the true spirit and scope of our invention.

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

1. An electroresponsive device comprising a movable armature and means for effecting a predetermined movement of the armature near a predetermined point of. the wave of an alternating electric quantity comprising means for exerting two opposing magnetic eifects on said armature respectively dependent on an alternating current and a direct current derived from said alternating electric quantity and having a predetermined ilxed magnitude relation to each other.

2. An electroresponsive device comprising a movable armature and means for effecting a pre- -determine'd movement of the armature near a predetermined point of the wave of an alternating electric quantity comprising means for exerting two opposing magnetic effects on said armature respectively dependent on an alternating current and a direct current derived from said alternating electric quantity and having a predetermined fixed magnitude relation to each other, and means for controlling the application of the magnetic effect due to said direct current.

3. An electroresponsive device comprising a movable armature and means for etlfecting a predetermined movement of the armature near a predetermined point of the wave of an alternating electric quantity comprising means for exerting two opposing magnetic eects on said armature respectively dependent on an alternating current and a direct current derived from said alternating electric quantity and having a predetermined tlxed magnitude relation to each other, means for controlling the application of the magnetic eifect due to said direct current, and means for preventing movement of the armaturev by the effect due to said direct current until after the direct current eiiect has been applied long enough to reach its steady state value.

4. An electroresponsive device comprising a movable armature and means for effecting a predetermined movement oi' the armature near a predetermined point of the wave of an alternating lpredetermined point of the wave of an alternating electric quantity comprising two magnetic circuits for controlling the movement of the armature, means for respectively energizing said two magnetic circuits by an alternating current quantity and a direct current quantity both derived from said alternating electric quantity and having a predetermined nxed magnitude relation to each other, and means tor controlling the application of said direct current quantity.

6. An electroresponsive device comprising a movable armature and means for eilecting a predetermined movement of the amature near a predetermined point oi.' the wave of an alternating electric quantity comprising two magnetic circuits for controlling the movement of the armature, means for respectively energizing' said two magnetic circuits by an alternating current quantity and a direct current quantity both derived from said alternating electric quantity and having a predeterminediixed magnitude relation to each other, means for controlling the application oi' said direct current quantity, and means for preventing movement of the armature in response to said direct current quantity energizetion until the ilux due to the direct current has reached its steady state value.

'1. Electroresponsive apparatus for eiecting the release of an electric switch conducting alternating current near the zero point of the current wave comprising a movable armature, two magnetic circuits for controlling the movement of said armature, and means for respectively energizing said two magnetic circuits by an alternating current and a direct current both dependent on the current conducted by the switch and having a predetermined ixed magnitude relation to each other.

8. Electroresponsive apparatus for effecting the Arelease of an electric' switch conducting alternating current near the zero point o! the current wave comprising a movable amature. two magnetic circuits for controlling the movement. oi said armature, means for respectively energizing said two magnetic circuits by an alternating current and a direct current both dependent on the current conducted by the switch and having a predetermined fixed magnitude relation to each other, and means i'or rendering one oi said magnetic circuits inil'ectlve until release o! the switch is desired.

9. Electroresponsive apparatus for eiecting the release of an electric switch conducting alternating current near the zero point of the current wave comprising a movable armature, two magnetic circuits for controlling` the movement of said armature, means for respectively energizing said two magnetic circuits by an alternating current and a direct current both dependent on the current conducted by the switch and having a predetermined xed magnitude relation to each other, means for rendering one of said magnetic' circuits ineffective until release of the switch is desired, and means i'or preventing movement of said armature under the eilect of said one oi' said magnetic circuits until the ilux in said circuit has reached a predetermined value.

10. In an electroresponsive device comprising a movable armature and means for effecting a predetermined movement of the armature near a predetermined point of the wave of an alternating electric quantity comprising means for exerting two opposing magnetic eiects on said armature respectively dependent on two currents derived from said alternating electric quantity and having a predetermined fixed magnitude relation to each other.

1l. An electroresponsive device comprising a movable armature and means for effecting a predetermined movement of the armature near a predetermined point of the wave of an alternating electric quantity comprising means for exerting two opposing magnetic effects on said armature respectively dependent on two currents derived from said alternating electric quantity and having a predetermined ixed magnitude relation to each other, and means for controlling the application of the magnetic eiect due to one of said currents.

12. An electroresponsive device comprising ya movable armature and means for effecting a predetermined movement ci the armature near a predetermined point of the wave of an alternating electric quantity comprising means for exerting two opposing magnetic effects on said armature respectively dependent on two currents derived from said alternating electric quantity and having a predetermined xed magnitude relation to each other. means for controlling the application of the magnetic effect due to one of said currents, and means for preventing movement of the amature by the eil'ect due to said one of .Mid currents until after the eiiect of said curreim nt has been applied for a predetermined t e.

vrx'roa Aroma; BERNHARD NERLICH.