DE192719C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

PATENT LETTERING

192719 CLASS 2 \ d. GROUP

in FRANKFURT a. M.

The poles of electrical machines often point as a result of unequal air spaces or unequal magnetic conditions, etc. when building the machine, which is sometimes unavoidable Differences in their field strengths. This is particularly the case when DC series armature can be used as a rotor. The runner becomes unequal attracted and there are considerable friction losses. With compensated AC motors as well as in repulsion engines also prevents the inequality of Pole strengths the creation of perfect rotating fields, so that not only additional iron losses arise, but also the machine, running noisily.

That asymmetry of the fields of an electrical machine is an essential cause of the noisy corridor has been proven by experiments.

According to the invention, the cause of the above-mentioned additional losses becomes as well as in many cases, e.g. B. thereby eliminating adverse noise in elevator operation, that the differences between the field strengths of different poles of the machines are eliminated. Be for this purpose one on the stand or on the rotor or on both parts of the machine or several short-circuit windings attached, which are wound in such a way that in Short-circuit currents are only induced in them by the mentioned asymmetry of the fields can while with completely even distribution of fields and uniform Field strengths short-circuit currents do not occur. The ones caused by the asymmetry of the fields Short-circuit currents, for their part, increase if the cross-section of the short-circuit windings is sufficient the asymmetry of the fields.

'The accompanying drawing shows exemplary embodiments some arrangements of the short-circuit winding through which the compensation the field strengths according to the invention is possible.

Fig. Ι shows the mode of action of the short-circuit winding b . Here, in a four-pole field excited by alternating current , the asymmetry represented by the field diagram NS ₁ -NS is canceled by two-pole windings bb , each of which includes a north pole and a south pole and which are short-circuited individually or - which is more useful - in series will. If the strength of the north pole enclosed by the winding were to be equal to the strength of the south pole likewise enclosed by the winding, then a short-circuit current would not arise. The short-circuit current induced in the winding b as a result of the predominance of the field strength of the north pole, however, causes a strengthening of the south pole and thus a compensation of the field strength. When the windings b are connected in series, not only do the field strengths of two poles balance one another, but also the field strengths of all poles of the machine.

The winding b. Can also be replaced by a

evenly distributed winding can be formed or at all according to any known Winding type be wound. The only condition is that the short-circuit winding has a number of poles that is an even multiple the number of poles of the other winding whose asymmetrical field is to be compensated, or vice versa that other winding is an even multiple of

ίο has number of poles in the short-circuit winding.

In the embodiment according to FIG. 2 it is shown how the middle grooves left free by the main winding a can be used to accommodate two short-circuit windings according to the invention b and c. If, according to FIG. 3, there is an even number of slots per pole, the two overlapping short-circuit systems d and e can be accommodated in the outer slots of each pole as shown.

It is expedient to combine short-circuit systems according to FIG. 2 with short-circuit systems according to FIG. 3, particularly in the case of an odd number of slots per pole, approximately in the manner shown in FIG. It should be noted that the short-circuit windings do not necessarily have to be symmetrical to the winding α . Rather, in the illustrated embodiments , all or part of the windings b, c, d, e can be adjusted to the right or to the left in one or more slots relative to the axis of the winding α. In general, however, one of the symmetrical arrangements will be chosen in order to facilitate the manufacture of the winding. .

With alternating current excitation, as mentioned, the short-circuit winding can be both on attach to the runner as well as to the stand. In the case of commutator machines, however, the arrangement on the stand is more practical, because most of the losses in these machines take place in the rotor and thus more winding space on the stator is available. In machines excited with direct current, however, the short-circuit winding must be used on the part of the machine that does not carry the excitation winding, i.e. when it is energized attach from the stand to the runner. '

In the case of DC armature winding, the only condition here is that the short-circuit winding has an even number of poles Multiple of the number of poles of the armature ", which is derived in a known manner from the number and Position of the collector brushes results.

In any case, the short-circuit winding which brings about the desired compensation has over the known equipotential connections the advantage that electrical connections between more than the actual connection points of the winding, their inequalities should be compensated, are avoided, as instead of the electrical connection of points of the same potential magnetic linkage of the poles occurs.

Claims (1)

Patent claim: Winding to balance the field strengths of different poles of an electrical machine, characterized by the application of one or more, if necessary mutually adjusted short-circuit windings, which in inductive interaction at the same time to a weaker and a stronger part of those Winding whose uneven field is to be compensated. 1 sheet of drawings.