Tacho clip nr 2 with more detail of the Landis&Gyr geartrain and opto's.
Three different T&N movements are shown, One is the synchronous seconds movement with 220 Volts motor
Next movement has the external seconds drive, and the third movement is from the Suchzeiger movement with 2.5 second increments.
The position of the actual clock hands on the drive shaft is also briefly shown