Measurement transformer for electric motor or incandescent lamp supply with over-current detection

摘要

The transformer includes at least one primary (1) and one secondary (2) winding coupled together via a transformer core (3). The load connected to the secondary winding having an ohmic resistance which is switched between two different resistance values (7,8). Pref. the secondary circuit also contains a rectifier (6) for rectifying the output current of the secondary winding. The switching between the two different load resistances is carried out by a transistor (9). A microprocessor (10) containing a comparator logic or controlled by computer software controls the switching transistor. The switching takes place in binary steps, esp., 1:8, 1:16, 1:32, etc.