The power section of the Tpa2..1B converters consists of a mixed single-phase bridge for the power supply of small power DC motors with separate excitation. As for the field power supply, the converter has a single-phase Graetz rectifier bridge supplied with an RC protection filter. In order not to overcome the form factor stated by the producer, it could be necessary to supply the armature circuit with a leveling choke. The adjustment to other voltages, frequencies and tacho reaction is obtained via resistors).