US1511075A - Current limiter - Google Patents

Description

Oct. 7 1924.

c. I. HALL CURRENT LIMITER Filed Jan. 25. 1921 Inventor: Che ter- 1. Hall Hi5 Attof'ney Patented Get. 7, 1924'.

UNITED STATES 1,511,015: PATENT oFFic E.

CHESTER I. HALL, 011' FORT WAYNE, INDIANA, ASSIGNOR' TO GENERAL ELECTRIC COIVIPANY, A CORPORATION OF NEW YORK.

CURRENT LIMITER.

Application filed January 25, 1921. Serial No. 439,867.

To all whom it may concern:

Be it known that I, CHESTER I. HALL, a citizen of the United States, residing at Fort Wayne, in the county of Allen, State of Indiana, have invented certain new and useful Improvements in Current Limiters, of which the following is a specification.

This invention relates to current limiters, and more particularly to such limiters arranged. to interrupt the supply to a load at short intervals when it reaches a definite maximum value.

Such devices have usually been built in the form of an electromagnet and an armature, the coil of the electromagnet being placed in series with the load and the armature serving to break the contact wien it is attracted by the elect-romagnet. This causes the deenergization of the. magnet and a corresponding resumption. of the load. If the load still exceeds the permissible value, the armature is again attracted and the load interrupted. This intermittent flickering continues until the load is reduced to the proper value. Such devices on the whole have certain disadvantages. For example, the length of time for which the cont acts are opened may be so short that such loads as heating devices may still be operated efficiently, although the current is on intermittently. It is one of the objects of my invention to render the time interval during which the contacts are open appreciably long so that no form of load whatever may be satisfactorily operated while this successive interruption of the circuit is taking place, and the customer in order to get satisfactory service is forced to reduce his load to the value agreed upon beforehand as the maximum permissible. Another object of my invention is to construct a device in such a way that an accurate adjustment may be made of the value of the: load at which the contacts will begin to open and close intermittently. Other objects and advantages will become apparent as the description proceeds.

For a better understanding of my invention reference is to be had to the following specification together with the accompanying drawings, in which Fig. 1 is a front view of the electromagnetic current limiter built according to my invention and a schematic wiring diagram showing its mode of Cooperating with the core 13 is a pivoted armature 14 having a stop 15, preferably of soft yielding material such as felt so as to reduce the noise during operation. The stop 15 acts against the end 16 of the armature 14 which is shown as appropriately weighted so as to keep it away from the pole far-e17 of the core 13. Metallic conductingpieces 18 and 19 are provided and securely fastened to the base 11, which conducting pieces serve to accommodate binding posts 20 and 21, as well as stop 15. The wires 22 and 23 connect these posts to the load and the source as indicated in Fig. 1. The circuit through the limiter and load may be traced as follows: wire 23, binding posts 21 and 2-1, electromagnet 12, a binding post 25 and from there to a pivoted lever or support 26 which carries a movable contact piece 27 and is appropriately weighted, as for example, by the weight 40. The movable contact piece 27 coacts withthe stationary contact piece .28 carried by the metallic member 18 to which the binding post 20 is connected. From binding post 20 the wire 22 leads to the load and the source. It is thus evident that the electromagnet 12 is in series with the load and hasits circuit completed through the movable contact 27 and stationary contact 28.

The pivoted support 26 is carried by a plate 29 securely fastened to the base 11. Furthermore, this support is so formed as shown in Fig. 2 that is extends directly above the pivoted armature 14 so that when said armature 14: is attracted to the pole on face 17 upon energization of the electromagnet 12, it strikes against said lever 26, rotating it in counterclockwise direction as viewed in Fi 2 and opening the contacts A1, 27 and 28. The armature must travel an appreciable distance before it strikes the lever 26, so that the contacts are opened at a high velocity. The moment of inertia of Weight 40 is sut'liciently great to cause the pivoted lever 26 to keep on traveling even after the armature 14% has reached the end of its travel toward pole face 17. The movement of the support 26 continues until it strikes the stop 30, in this instance, formed integral with plate 29. By the time the lever 26 returns to the normal position shown in Fig. 2 an appreciable interval of time has elapsed so that a heating device, for example, could not be efficiently operated. The pivoted lever 26 and the stop 30 are so arranged that there is no danger of this lever staying in the open position, since the force of gravity always tends to close the contacts.

Under some circumstances it may be advisable to reduce the load to an inappreciable constant value in case a very large load. is attempted to be taken. For'example, it as much as three or four times the limiting load is reached, it may be advisable to shunt the contact pieces 27 and 28 by a comparatively large resistance so that upon opening of the contacts there is still a path for the current through this resistance, and it the load is suiiiciently great this current is large enough to attract armature 1 1 and hold it in its attracted position. Under such circumstances, a small steady load is obtained, until the number or kind of translating devices making up the load is changed nearer to normal. lVhen this happens the armature lat is released and the resistance 31 short circuited.

One of the main features of my invention resides in the particular way in which the core 13 for the electromagnet 12 is supported, so that accurate adjustment of the air gap between the armature 1e and the pole face 17' may be obtained. F or this purpose I pivot the armature it upon the core member 13 by means of the pivot pin 32. Adjacent to this pivot pin 32 I provide a pivotal sup port 33 tor the entire core 13. This pivotal support fastens to the base 11 as may be ascertained by an inspection of Fig. 2. The other end of the core 13 carries a member provided with a slot 3 1 through which p asses appropriate fastening means such as a. screw 35, so as to hold the core in its adjusted position about the pivotal support 33. It is evident that by loosening the screw 35 and turning the entire core about 33 a pivot, which pivot has an axis perpendicular to the plane of movement of the armature 14, the pole face 12' may be brought nearer to or further from the armature 14:. After the proper adjustment is made the fastening means 35 may again be tightened. Thus an extremely accurate adjustment of the air gap between the armature and core is obtained. The screw is in this instance shown as threaded. into a member 36 rigidly fastened to the base 11. Furthermore, the slot 34 is ajjiprcpriatcly carried by the bottom plate 37 oi? the core between which plate and the top plate 38 the laminations of the core are compressed. F or compressing these lai'ninations the pivotal support may be used, as well as another fastening means such as the screw 39.

hile I have shown in the accompanying drawings but one embodiment of my invention, I do not wish to be limited thereto but aim to embrace in the appended claims all modifications falling tairly within the scope of my invention.

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

1. In a current limiter having contacts, an electromagnet, acore for said electromagnet, an armature for operating the contacts, a pivotal support for said core, a pivot carried by said core for the armature adjacent the pivotal support for the core, said parts being so arranged that the adjustment of the core about its pivot changes the deenergized position of the armature with respect to the core, and means for adjusting the angular position oi said core about its pivotal support.

2. In a current limiter having contacts, an electromagnet, a core for said electromagnet, an armature for operating the contacts, a pivot for said armature carried by said core, a base for independently supporting the contacts and electromagnet, a pivotal support extending from the base through the core adjacent the pivot for the armature, said core having a slot. and fastening means passing through said slot, whereby said core may be angularly adjusted about its pivotal support.

In witness whereof, I have hereunto set my hand this Zeth day of January, 1921.

CHESTER I. HALL.

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