HK1122397B - On-load tap changer with an energy storage mechanism - Google Patents

Description

The invention relates to a load step switch with a power storage device for continuous switching between different winding contacts of a loaded step transformer.

Err1:Expecting ',' delimiter: line 1 column 150 (char 149)

The power storage of this well-known load-level switch has a spring plate to which several pulling springs with one end each are attached, which are directed at their other end to bearings. The spring plate, in turn, is rotatable at its free end to a drive shaft. The drive shaft, which is attached to a switch shaft, is actuated via a free-run of a drive element stored centrally on the switch shaft and independently of this switch shaft. The switch shaft carries a malt gearbox carrier at its bottom side.

The wall of the insulating tube contains fixed step contacts in several horizontal layers, which can be switched on at any level by one of the switch elements on the switch column.

The mechanism of action of this known force storage is as follows: At the beginning of a planned load changeover, i.e. the changeover from one winding to another winding, the drive element is turned slowly and continuously, usually by a motor drive, which takes the drive shaft and the end of the spring plate attached to it with it by means of a stroke, thereby deflecting and stretching the draw spring. After a 180° turn, when the draw spring has reached its maximum deflection, the free-running drive element does not interfere with the drive shaft. This rapid rotation of the drive cranks is transferred to the crankshaft crankshaft of the crankshaft gearbox and thus to the switch column; the switching elements attached to it switch in a leaping manner to adjacent fixed step contacts.

This force storage has been proven for many years in various step switches. However, the traction springs used are not mechanically durable indefinitely, but must be replaced after a certain operating time or number of switches for safety reasons. Until now, this was not a problem, since after such a number of switches inspections were usually carried out on the load switches anyway. However, due to the high reliability of the vacuum switches now available and used and the advantages of the reliability technology as a whole, the maintenance intervals of the load switches can now be increased, so that the limited mechanical stability of the traction switches used in the well-known permanent power switches is increasingly becoming apparent.

The purpose of the invention is therefore to indicate a type of load switch, as described in EP 0 355 814, with a force storage device incorporating force storage springs as energy storage devices, which has a higher mechanical durability.

This task is solved by a load-level switch with power storage with the characteristics of the first claim.

The advantage of the invention, in addition to the intended near-unlimited mechanical strength of the pressure springs used, the breakage of which is practically impossible, is that, in a particularly advantageous embodiment of the invention, the force storage device can be continuously adjusted by the use of an adjustable pull rod with a thread, which makes it possible to adjust the force storage device in advance to the most different types of load switches and to adjust the force released after release in a simple way. The force storage device is suitable for a wide variety of load levels and can be used both in oil switches with mechanical contacts and in vacuum switches.

The invention is further explained below by means of illustrative drawings showing: Figure 1 shows the upper part of a load switcher with power storage in perspective, as described in the invention.

The first is a gear 3 connected to the non-shown motor drive shaft, the third is a gear 3 that drives a drive 4 through its gear 5. The fourth has two symmetrical connectors 6 corresponding to a drive 8 and this will be explained further below. The third is a gear 8 connected to the drive 8 and the third is a gear 9 connected to a 10 speed train. The second is a gear 10 connected to a 12 speed train. This gear is connected to a 12 speed train in the bottom of the train, and the third is a 12 speed train.

The invention provides for a spring tube 14 to be placed around the retractor 10 described above. The spring tube 14 is attached to a bearing buckle 15 on one side; it is horizontal deflectable by means of a vertical bearing bolt 16. An internal pressure spring 17 is provided between the spring rod 10 and the spring tube 14, an external pressure spring 18 is concentrically located outside the spring tube 18. In the example shown here, an arrangement with an internal pressure spring 17 and an external pressure spring 18 is provided to produce high forces. However, it is also possible to provide for a single pressure spring, either inside or outside the spring tube 14, as part of the invention. More than two such springs may also be provided.In the embodiment of the invention shown in Figure 1, the inner spring 17 and outer spring 18 are supported on one side by a fixed spring support 19 connected to the spring tube 14. On the other side, the inner spring 17 is supported by a movable inner spring 20 only shown in Figure 2 and the outer spring 18 by a movable outer spring 21 external spring 20 and 21 are connected to the free end of the drawbar 10. The inner spring 20 is attached directly to the drawbar 10.The spring 22 is equipped with a longitudinal bolt 22 protruding outwards, connecting spring 10 and spring 21 to each other. Figure 1 shows a further reel 24 which interacts with another malt wheel 25 which, as is well known, operates a position indicator 26 and, as is also well known, a dial.

Err1:Expecting ',' delimiter: line 1 column 471 (char 470)After a 180° rotation of the drive shaft 8 the drawbar 10 has reached its new final position; the pressure springs 17, 18 are at their maximum tension, i.e. compressed. After the deadline has been passed, the previously formally coherent attachment 6 or 7 is disengaged and the rotation of the drive shafts 8 and thus the switch shaft 11 is completed quickly, as the pressure springs 17, 18 relax in a jumpy manner.

The present invention is illustrated in Figure 2 in a lateral section, but the other components, which are only partially illustrated for completeness, are not explained in detail. It can be seen here that, after a particularly advantageous development of the invention, the drawbar 10 is screwed at one end by a thread 27 with the inner spring bearing 20. This thread 27, particularly advantageously shaped as a fine winding, results in an adjustable drawbar 10 in which the effective length between the fixed spring bearing 19 and the movable spring bearing 20, 21 can be easily changed. This allows a continuous adjustment of the spring lengths of the pressure springs 17, 18 and thus the effective spring forces in a simple way. The force storage can be easily adapted in this embodiment to the specific energy requirements of the released force storage shapes, which can vary depending on the type of switch and the type of switch.

It is also possible to realize the adjustability of the drawbar 10 by means of a further thread 28 at the drawbar head 9.

Claims (3)

1. On-load tap changer with an energy storage mechanism for uninterrupted changing over between different winding taps of a tapped transformer under load, wherein the on-load tap changer comprises an insulating material cylinder, in the wall of which fixed tap contacts able to be electrically contacted are arranged, wherein centrally arranged in the interior of the insulating material cylinder is a rotatable switch column which is drivable by a drive crank and carries at least one switching element able to be contacted with the fixed tap contacts, and wherein the drive crank is mechanically connected with two energy storage springs in such a manner that at the beginning of each changeover the drive crank is rotated and the two energy storage springs are stressed, characterised in that the two energy storage springs are compression springs (17, 18) which are each supported by one end thereof at a common fixed spring counter-bearing (19), a tie rod (10) is arranged at the drive crank (8), a spring tube (14) pivotably connected with a bearing block (15) is provided around the tie rod (10), the fixed spring counter-bearing (19) is fastened to the spring tube (14), one compression spring (17, 18) is arranged within the spring tube (14) and the other compression spring (18) is arranged concentrically outside the spring tube (14) and surrounding this, arranged at the tie rod (10) is an inner movable spring counter-bearing (20) as well as an outer movable spring counter-bearing (21), at each of which the other end of a respective one of the two compression springs (17, 18) is supported, the inner spring counter-bearing (20) within the spring tube (14) is fastened directly to the tie rod and the outer spring counter-bearing (21) outside the spring tube (14) is connected with the tie rod (10) by means of a fastening pin (23) which projects outwardly through longitudinal cut-outs (22) in the spring tube (14).
2. On-load tap changer according to claim 1, characterised in that the tie rod (10) is directly screwed to the movable inner spring counter-bearing (20) by means of a thread (27).
3. On-load tap changer according to claim 1 or 2, characterised in that the tie rod (10) is screwed to a tie rod head (9), which is rotatably mounted on the drive crank (8), by means of a further thread (28).