DE744205C - Transformer for fine-level control through a contact piece that grinds on n parallel, isolated from one another and bare-made windings on the same leg at the contact points - Google Patents

Description

Transformer for fine-level regulation through a contact piece that on n parallel, isolated from each other and made blank at the contact points Windings on the same leg dragging There are already regulating transformers with the excitation winding lying on one leg and regulating winding arranged above it known, in which the turns of the control winding are partly made bare and the voltage is taken from a sliding contact on the control winding. One Such a design has the disadvantage that when moving from one to the other Turn always a relatively large short-circuit current occurs. To now this To keep short-circuit current and the sparks caused by it as small as possible one went over to making the spread of the control winding as large as possible. It is also known to produce the same contact from carbon or one as possible to choose a small winding voltage. The last-mentioned remedy is still there best proven. It can be used without further ado in the case of small services but in the case of greater achievements, the designs are so abnormal that they are no longer economical are.

A winding is already available as a control winding for higher outputs used, which consists of 2 or n parallel, mutually insulated windings, where between every two adjacent turns i / 2 or i / n is the voltage of one turn is available. In such regulating transformers, two are bridged Windings due to the sliding contact always only i / 2 or = / n winding voltage in the Short circuit to effect. Here, too, is a relatively large one Short-circuit current present.

The object of the invention is to create a regulating transformer in which the voltage difference between the two windings completely or almost disappears during the bridging of two adjacent turns by the sliding contact, so that the short-circuit current flowing through the sliding contact is practically zero or only low values can accept. The invention relates to a transformer for fine control by means of a contact piece which is bare on n parallel, mutually insulated and deri contact points made windings on the same shea grinds. According to the invention are of the '" allelic windings always two next to each other lying windings with their `Vicklungsan` ' gen or winding ends to the two. Endeix @ The secondary winding of a three-legged, depending on the load, a flux displacement to one or the other outer leg is connected to the scatter transformer, which carries the excitation winding on its middle leg and the secondary winding on one outer leg, which emits the i / n Windungsspanriung of the main transformer.

This transformer version with a very small short-circuit current can also be built economically for larger outputs, as it allows larger ones To use leg cross-sections and therefore higher winding voltages than before.

The drawing shows exemplary embodiments of the invention. Fig. I shows an autotransformer with two parallel, mutually insulated windings 2, 3 on the same leg, which also carries the excitation winding i. q. is intended to schematically represent the section through the two '' windings 2 and 3; a to l are then the individual turns in the section. The contact piece ii slides on these turns. The winding beginnings of the windings 2 and 3 are connected to the two ends of the secondary winding 7 of a three-legged, depending on the load, a flux displacement to one or the other outer leg 8 or = o having scatter transformer 5. Its middle leg g carries the excitation winding 6. The secondary winding 7 sits on the outer leg 8; it gives off T / n `Vindungs voltage of the autotransformer. The regulated voltage is picked up between lines 12 and 13, while the excitation voltage is applied to lines o and i: z.

The mode of operation is as follows: The excitation winding i generates the same winding voltage in the windings 2, 3. The leakage transformer 5 is excited by the excitation winding 6 so that in the case where no load current flows through the secondary winding 7, this winding delivers half the winding voltage of the autotransformer. The contact piece ii sliding on the turns of the windings 2, 3 of the autotransformer must be somewhat narrower than one turn thickness, so that a maximum of two turns can be bridged, but never three adjacent turns. If the contact piece ii rests on only one turn, the load current flows through one of the windings 2, 3, either directly to the line 12 or via the secondary winding 7 of the leakage transformer to the line 12. In the latter case, the excitation winding 6 also takes current in the same ratio as the secondary winding 7, since between the windings 6 d 7 normal transformer ratios j , are available, albeit with a large If the contact piece ii comes to lie on two windings, the following two cases can arise:

occur: In one case, both are parallel windings the same number of turns switched on. Between the two winding parts in which the same voltage is induced, the leakage transformer 5, if none Load current flows through its secondary winding 7, which emits half the winding voltage. This now causes a short-circuit current in the short-circuit circuit. Flows but there is a current in the winding 7, so the flow of the power flow is hindered and displaced from leg 8 to leg io. By the displacement of the river from the thigh 8 after leg io is now the voltage induced in the short-circuit circuit almost destroyed and therefore also the short-circuit current flowing in the short-circuit circuit. Thus, apart from the load current, only a very small current flows through the contact piece Short-circuit current that serves to destroy the flow in leg 8.

In the other case prevails in the by the contact piece ii. bridged two conduction paths a voltage difference of one turn. Through the distribution transformer this voltage difference is reduced to half the winding voltage of the autotransformer degraded. An operating current flows from both contact points to the contact piece ii. At the same time flows in the circuit formed from the contact piece ii, the two conduction paths and the winding 7 a short-circuit current of the half Turns voltage in this circuit. This short circuit current has the opposite Direction as in the case where two contact points with the same number of turns through Contact piece ii to be bridged, since now coils 6 and 7 opposite current flow to have.

As a result, the one that penetrates the leg io of the leakage transformer 5 is now River displaced after leg 8. Since thus the whole flow of the leakage transformer passes through coil 7, it also doubles the voltage present in the open circuit induced in the coil 7. The coil 7 now has a voltage that is the full one Turns voltage of the autotransformer. This will make the voltage difference balanced in the two current paths to the contact piece ii and the short-circuit current almost destroyed. The coils 6 and 7 of the leakage transformer can be connected to any point on the two windings of the autotransformer, expedient. however, they are attached to the beginnings or ends of the windings of the autotransformer connected.

The simplest version of the scatter transformer is the one with a Three-leg core, with the three legs having the same cross-section. The excitation winding 6 of the scatter transformer can also be from an auxiliary winding of the autotransformer be fed. In Fig. _ The excitation winding i des is fed Autotransformer off.

Fig. 2 shows a three-phase transformer with two parallel, isolated from each other and made bare at the contact points on windings each leg shown. Any three-legged distribution transformer for the two of them bare windings 2, 3 on each leg of the main transformer assembled here with the main transformer in such a way that its secondary winding 32 or 33 or 34 half the power flow of the associated main transformer leg 16, 17 and 18 respectively. Each leg of the main transformer is in place at i9 or 2o or 21: expanded to approximately double the cross-section and received in the In the middle a groove for the secondary winding 32 or 33 or 34.

The mode of operation of the built-in leakage transformers is the same like the one shown in Fig. i for a separately arranged scatter transformer.

Fig. 3 shows schematically an arrangement with four parallel to each other isolated windings 2, 3, 14, 13 made bare at the contact points same thigh. Here three scatter transformers 5, 26, 27 are required, which are excited by the windings 6, 28, 3o in such a way that each secondary winding 7 or 29 or 31 in the event that no load current flows through them, a quarter the winding pitch of the main transformer. The contact piece may in this Trap not more than three turns thick, so that a maximum of four turns be bridged.

The transformer according to the invention can also be designed with taps that lead to a special contact path on which the contact piece slides. The shape of the magnet frame of the scatter transformer or transformer can also differ from the one shown, but the requirement must always be met that the power flow generated by the excitation coil divides into two almost equal halves divides and the secondary coil encloses only half of the power flow.

Claims (3)

PATENT APPLICATIONS: i. Transformer for fine-level control through a contact piece, that on n parallel, isolated from each other and made blank at the contact points Windings on the same leg grinds, characterized in that of the parallel windings always have two windings next to each other with their winding beginnings or winding ends to the two ends of the secondary winding of a three-legged, Depending on the load, a flow displacement towards one or the other outer leg having scattered transformer are connected, which is on its middle limb the excitation winding and the secondary winding on one outer leg, outputs the i / n winding voltage of the main transformer. 2. Three-phase transformer with two parallel, isolated from each other and made blank at the contact points Windings on each leg according to claim i, characterized in that each three-legged scatter transformer for the two bare windings each leg of the main transformer assembled with the main transformer in this way is that its secondary winding half the power flow of the associated main transformer leg includes (Fig. 2). 3. Transformer according to claim 2, characterized in that the Total cross-section of each main transformer leg at the point where the Secondary winding of the leakage transformer is located, is enlarged. For demarcation the subject of the application from the state of the art is the following in the granting procedure Publication considered: German patent specification. . .. ... . No. 633 948.