| 摘要 |
An electrical heating apparatus is connected by means of a plurality of heating resistors (2 to 7) to a three-phase AC network (RYB, N) in a star circuit. In order to achieve the rated power even on networks having a different rated voltage, the resistance values of first heating resistors (2, 3, 4) are designed such that the first heating resistors (2 to 4) provide the rated power on their own at the maximum rated voltage (277 V). The resistance values of second heating resistors (5, 6, 7) are designed such that the second and first heating resistors (2 to 7) together provide the rated power at the lowest rated voltage (207 V). The resistance values of the second heating resistors (5 to 7) and of the first heating resistors (2 to 4) are designed to be different such that, at a mean rated voltage (240 V), the first heating resistors (2 to 4) together with one of the second heating resistors (7) provide the rated power. <IMAGE>
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