Called a Motor Generator used to test equipment I occasionally designed for England, Europe and Australia.
Step 1: MOTOR
Step 2: CONNECTING MOTOR TO GENERATOR
These machines are how 50 Cycle power was generated before
the semiconductor was invented at Bell Labs.
And were known as MG Set ( Motor Generator Setup ).
Well ... Yes ... Vacuum Tubes like the Thyratron tube
which is the Vacuum tube equivalent of the SCR Silicon Controlled Rectifier
and Mercury vapor tube devices could make 50 cycle electronic supplies
before the advent of semiconductors.
Of course tubes generate Heat and take up a large volume even compared to the MG Set.
Here is a video what they looked like long ago.
Video By Radu Motisan
Step 3: WATCH IT RUN
... Only about 15 seconds ...
Step 4: WIRING THE SYSTEM
Power comes through the gray power cord.
The system diagram shows the 60 Hz input power Motorswitch with a duplex outlet.
The output power 50 cycle wiring feeds the right half of the Double Duplex outlet.
Only the 100 VAC Outlet is active all the time when running..
When 240 VAC is needed, the transformer is plugged into the Right 100VAC outlet .
This delivers power to the Left 240VAC 50 Hz outlet.
The transformer is designed for both 50 and 60 cycle operation.
That means it has been designed for 50 Hz and will run even cooler at 60 Hz.