Umformer U10a1

This is the power supply dynamotor for the 10W.S.c transmitter.

The operating concept involves a 12.6 DC Volt power supply from either a battery or an alternator, that spins a motor generator. A portion of the 12.6 DC Volt current goes straight to the 10W.S.c and supplies the filament voltage for the vacuum tubes and a current of approximately 6.7 Amps. The umformer generator produces approximately 400 Volts without a load for the anode voltage. When the 10W.S.c is connected to the umformer and powered on, the voltage drops to around 350 VDC and 115 mA due to the increased internal resistance of the transmitter. The umformer is switched on by a 12 Volt relay that gets activated from the power switch of the transmitter.




The U10a is in excellent condition with original paint. It is stamped "Ark" to indicate that it can withstand very cold climates.



The motor rotates at 3500 RPM.



The inside of the lid has a conveniently placed electrical schematic.



The umformer with the cover off. The materials are mostly zinc alloys since this is a late-war model. The famous AEG is the manufacturer. It is the largest electronics company in Germany at that time.



The motor shaft has been removed from the cowling for cleaning and lubrication.



The motor shaft. At the top of the photo is the motor drive section, and at the left bottom is the generator section.



Closeup of the original ball-bearings during cleaning. Based on the English word "Germany" these ball-bearings were produced for export.



Disassembled motor component that contains the brush holders and the Bakelite gasket that can be adjusted for the brush placement angle. One of the brushes can be seen on the top right.



View of the case with the motor removed.