U.S. Naval Observatory, Washington. Auxiliary apparatus, consisting of motor-generator with adjustable speed control and phase shifter, which supplies current for the synchronous motor
Titre
U.S. Naval Observatory, Washington. Auxiliary apparatus, consisting of motor-generator with adjustable speed control and phase shifter, which supplies current for the synchronous motor
Type
photographie : tirage photographique gélatino-bromure d’argent contrecollée sur carton
