Immagini

DESCRIPTION

Exhibit 452 is a Hartmann electrodynamometer in which the input current flows first through two fixed coils and then through a rotatable coil which is perpendicular to the fixed coils at zero current. As the current increases the field from the fixed coils causes rotation of the rotatable coil which has an increasing magnetic moment so that the torsion on the supporting wire is proportional to the square of the current. The deflection of the mirror attached to the torsional support is read by the Poggendorff method. Since an inversion of the current is sensed in both the fixed and the mobile coils, this instrument can be used for both direct and alternating current. The instrument rests on a brass base with three leveling screws.

ISCRIZIONI

1. Sulla base di ottone è inciso: HARTMANN & BRAUN FRANKFURT A/M No. 35.

BIBLIOGRAPHY

• [1] Fleury P., Mathieu J.P., "Elettrostatica Corrente continua Magnetismo", Zanichelli Editore, Bologna, 1970, Pag. 262.
• [2] URL [ http://www.tpub.com/content/neets/14188/css/14188_98.htm ] e pagine seguenti.

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