DE246434C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

PATENT LETTERING

■ - JVl 246434 -r. CLASS 21 d. GROUP

Addendum to patent 241770 of June 18, 1909.

Patented in the German Empire on September 10, 1910. Longest duration: June 17, 1924.

Patent 241770 describes a method by means of which it is possible to compensate the transformer EMF in the windings short-circuited by the brushes by influencing the auxiliary pole excitation winding with the primary current of the shunt transformer used to excite the main field (working field). Usually one cannot switch the auxiliary pole exciter winding directly into the exciter circuit for dimensioning reasons, but has to do it via a current transformer. The size of this transformer can now be significantly reduced if, instead of feeding the auxiliary pole exciter winding directly with the primary current i _{i of} the shunt transformer, it is fed with the two summands of the latter, the secondary current i _% and I ₁ -I ₂ , which occur on the exciter transformer . The accompanying Fig. 1 shows an embodiment. B is the exciter transformer, A the collector machine, A ₁ , A ₂ , A ₃ their compensation windings, e the exciter windings of the main poles, A ₁ , A ₂ , A ₃ the auxiliary pole exciter windings; these latter are fed according to the invention simultaneously by the current i ₂ (secondary excitation current) and the current I ₁ -I ₂ . To make this possible, the current ^ ₁ -J _{2 is} fed via a current transformer C. This transformer can be built for a considerably smaller power compared to a transformer in the primary circuit, because the excitation transformer B is partly used for transforming the current feeding the auxiliary pole excitation winding, so that only part of the excitation power of the auxiliary poles is converted in transformer C. while the other part is fed directly. .

In Fig. 2, the excitation transformer B with the current transformer C is particularly drawn out for the case that B is a two-coil transformer. A current i ₂ and I ₁ -I ₂ can then also be taken from the transformer B. As can be seen, the current distribution is achieved in exactly the same way as in FIG.

Another exemplary embodiment is given by FIG. 3. Here a single-phase collector motor is fed from a three-phase network. It means N the three-phase network, A the rotor, k the compensation winding, A the reversing pole winding, e the excitation winding of the single-phase motor. B is a three-phase autotransformer in star connection, the winding I of which is the excitation current i ₂ for the excitation winding e and via the contact k

Claims (1)

the differential _{current Z 1} -1 ₂ - to feed the current transformer C is taken in one phase. As can be seen, the reversing pole winding h is traversed by the current ■ (i _x - i ₂ ) - \ - i ₂ . The armature A and the compensation winding k are connected in series and are connected to the same line phase as the two windings 2 and 3 of the autotransformer. the two streams « ₂ and h-h result ίο always a cumulative effect that is equivalent to the primary current i _x , so the derivatives specified in the main patent apply, and the compensation is completely exact for all periods and voltages. You could of course, instead of a common winding on the auxiliary poles, two Use separate windings for both currents, but would then have a lot of copper outlay. Patent application: Device for the excitation of auxiliary poles to compensate the transformer EMF in single or multi-phase collector machines according to patent 241770, characterized in that the primary current (ij of the shunt transformer used to excite the main field of the auxiliary pole exciter windings in its two summands occurring on the transformer, the secondary current (i _t and ίχ-ί%), is supplied separately, namely the latter by means of a current transformer. 1 sheet of drawings.