DE447750C - Overcurrent relay for parallel lines - Google Patents

Description

GERMAN EMPIRE

ISSUED ON 30 JUL11927

REICH PATENT OFFICE

PATENT LETTERING

CLASS 21c GROUP

V2101 $ VIII ^ IC *

Voigt & Haeffner Akt-Ges. in Frankfurt a. M. *).

Overcurrent relay for parallel lines. Patented in the German Empire on February 25, 1926.

The present innovation shows an arrangement for protecting two parallel lines a single differential relay that also works in the event of overcurrent and the desired There is a contact for switching off if only one of the parallel lines is in operation. Here the special arrangement is made that the sensitivity of the relay of the Voltage decrease is made dependent in order to prevent that in an operational Asymmetry ia ^ len parallel lines Shutdown takes place. This is achieved by each having two outer legs of a three-legged magnetic core, the sum or difference of the currents of the two parallel Acts lines. A magnet armature is rotatably attached to the middle leg. But this also acts on them magnetic forces of the two outer legs still a special magnetic coil /, which is applied to the operating voltage. Just if the latter has fallen by a certain amount and at the same time one of the two lines is faulty, e.g. B. if by reversing the direction of current in a line the difference the currents acting on the magnetic leg is no longer zero, the magnet armature becomes close a contact that switches off both lines. Is also at times one of the If both parallel lines are out of operation, the relay is still able to work.

The figure shows an embodiment, α and b are the parallel lines drawn in single-phase, c is the three-

^k ) The patent seeker indicated as the inventor:

Peter Klaas v. d. Sterr in Frankfurt a. M.

limb magnetic core, d the armature, which is rotatably arranged around the middle limb. This is attacked by a spring. If the armature is attracted, an Eontakt / disconnects the lines closes. g and h are the current transformers that feed the coils g ¹ , g ² and h ¹ , h ^{2, respectively.} In normal operation, the coil g · ¹ , // ¹ cause the left leg of the armature d to be attracted, since the counterforce, namely the magnetic force of the coils g ² , A ² , is approximately zero. The voltage coil i also acts on the armature d .

If an overcurrent occurs outside the parallel lines, nothing changes in the magnetic force distribution, since the magnetic force flow is only increased, but a drop in voltage has no effect on the relay. In the event of a short circuit on one of the parallel. Lines, e.g. B. the line a, the current direction reverses in this, the magnetic force of the coil g · ¹ , A ¹ is almost zero, that of the coils g · ² , h? add up. At the same time, the voltage decreases in accordance with the short-circuit current that occurs, so that the effect of the coil / on the armature d decreases. The latter is attracted under the action of g · ² , A ^2.

The lines are then switched off by making contact with /. If only one of the parallel lines is in operation, e.g. B. line b, the magnetic force of coil A ^{2 is} equal to that of coil A ¹ plus the force of spring e. In the event of an overcurrent, the magnetic force of the coil A ² 'will increase more strongly, and since the voltage drops at the same time, the attraction force of the magnet ζ also decreases, so that a switch-off can take place.

Claims (1)

Claim: Overcurrent relay for parallel lines that depends on the sum or Difference in the currents of the parallel lines works, characterized in that on the outer throat of a three-legged Magnet core windings from each wire sit and on the on the middle leg located armature act, and that another voltage-influenced Magnet is arranged to operate the device in the case of operational asymmetry in the parallel To prevent lines and to cause a shutdown only when at Errors in one of the two lines, a corresponding voltage drop occurs.