The operating life of endoscopy capsules is limited by the batteries needed for use. The capacity of corresponding batteries, however, is too short to cover the total period of gastrointestinal transit. To overcome this limitation, a novel kind of wireless power transmission was used. It utilizes a permanent magnetic cylinder located outside the patient’s body and is turned by an electric motor, thereby generating a rotating magnetic field. This field in turn causes the motor, by a permanent magnetic sphere, located in a liquid bearing inside the endoscopy capsule, to rotate synchronously. The sphere induces an alternating voltage in coils inside the capsule and thus provides the necessary power. This arrangement was able to transmit power of up to 170 mW. This value is clearly higher than the minimum power of 100 mW needed to operate the electronics of the endoscopy capsules that are actually in use. The volume of both the sphere and the induction coil is smaller than the batteries that are actually integrated in the capsules. By this means, the operating time may be prolonged, in principle up to arbitrary values.

中文翻译：

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内窥镜胶囊中的无线电力传输

内窥镜胶囊的使用寿命受到使用所需电池的限制。然而，相应电池的容量太短，无法覆盖胃肠道运输的总时间。为了克服这一限制，使用了一种新型的无线电力传输。它利用位于患者体外的永磁圆柱体并由电动机转动，从而产生旋转磁场。该磁场继而通过位于内窥镜胶囊内的液体轴承中的永磁球使电机同步旋转。球体在胶囊内的线圈中感应出交流电压，从而提供必要的电力。这种安排能够传输高达 170 mW 的功率。该值明显高于操作实际使用的内窥镜胶囊的电子设备所需的 100 mW 的最小功率。球体和感应线圈的体积都小于实际集成在胶囊中的电池。通过这种方式，操作时间可以延长，原则上可以延长到任意值。