| 摘要 |
The invention relates to a protection device for an externally excited DC machine. The first connection of the field winding (12) of the machine is in this case connected via a first relay contact (18a) to a field current adjuster (4), which is connected on the other side to the negative terminal (2) of a supply voltage source. The second connection of the field winding (12) is connected via a second relay contact (17a) and a transistor (9) to the positive terminal (1) of the supply voltage source. A first capacitor (7) is connected between the positive terminal and the negative terminal as a field energy store in the event of a disturbance. A second capacitor (6), which is connected to the positive terminal (1) and has a resistor (5) connected in parallel, is likewise connected to the second relay contact (17a) via a diode (16). The control connection of the transistor (9) is likewise connected to the positive terminal (1), via a third relay contact (8a). The field winding (12) is connected via in each case one diode (11 and 15) to the supply voltage source. In the event of a disturbance, the third relay contact (8a) opens first, so that the energy of the field winding (12) is partially stored in the capacitor (6). Subsequently, the further relay contacts (17a, 18a) also open, and the remaining energy of the field is stored in the capacitor (7). <IMAGE>
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