» Sonic Wheel (0212)
Immagini
DESCRIPTION
Exhibit 212 is a sonic wheel, a constant speed electric motor designed in 1897 by the Danish physicist Paul La Cour (1846-1908) to regulate motion synchronization and determine the frequency of electric tuning forks. The sonic wheel is a toothed wheel in which the teeth are attracted by electromagnets which advance the wheel. The currents in the electromagnets are controlled by a switch attached to one of the arms of a tuning fork. The velocity of rotation of the sonic wheel thus depends on the frequency of vibration of the tuning fork and is inversely proportional to the number of teeth on the wheel. The instrument consiste of an iron cylinder whose circumference is divided in vertical bars about one cm wide as the teeth. The cylinder is surrounded by five fixed coils in series. The turns of the cylinder are counted by a counter composed of two wheels: one counts the single turns and the other the rotation of the latter.ISCRIZIONI
- Incisione sulla base: "Max Kohl A. G. Chenmitz"
BIBLIOGRAPHY
- [1] Max Kohl, Chemnitz - Physikalische Apparate - Preislist N.r 21
Dati Catalografici
| Data di costruzione: | --- |
|---|---|
| Data di carico: | 1923-11-22 |
| Nr. Inventario: | 4080 (Generale dal 1874) |
| Costruttore: | Max Kohl A.G. |
| Materiale: | ferro, ottone, pietra dura, vetro |
| Dimensioni: | 30 cm x 30 cm x 15 cm |
| Conservazione: | buono (Le bobine sono molto impolverate e non è facile pulirle. Per il resto sembra tutto a posto, salvo una delle lancette del contagiri che è un po' storta. Manca il diapason con la cassa di risonanza, che nel catalogo appare con voce separata, ma abbinato alla ruota fonica.) |