Faraday wheel
Date: circa 1950
Inventory Number: 1997-1-1341
Classification: Electromagnetic Apparatus
Maker: Central Scientific Company (1889 - 2000)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
10 × 17.8 × 12.7 cm (3 15/16 × 7 × 5 in.)
Description:
A rectangular metal base with a bevelled edge. In the top and bottom right corners, are two cylindrical outlets, the top is red, and the bottom is black. To the left of the black outlet is the nameplate.
In the center of this base is a 'G' shaped magnet; unlike the letter 'G', however, the crossbar of this magnet runs outward instead of inward. Between the arms of the magnet is a vertical copper disc. The entire rim of the copper disc is worn away. (A thin recessed area was excavated from the base underneath the disc.) A black component that looks like a tuning fork holds up the disc. The disc is between the two 'tuning fork' arms which hover over the top of the magnet. The 'tuning fork' and disc are all connected by a threaded rod. The other side of the tuning fork is affixed at its height by a black U-shaped component. On either side of the magnet is a silvery metal clamps.
In the center of this base is a 'G' shaped magnet; unlike the letter 'G', however, the crossbar of this magnet runs outward instead of inward. Between the arms of the magnet is a vertical copper disc. The entire rim of the copper disc is worn away. (A thin recessed area was excavated from the base underneath the disc.) A black component that looks like a tuning fork holds up the disc. The disc is between the two 'tuning fork' arms which hover over the top of the magnet. The 'tuning fork' and disc are all connected by a threaded rod. The other side of the tuning fork is affixed at its height by a black U-shaped component. On either side of the magnet is a silvery metal clamps.
Signedon faceplate: CENTRAL SCIENTIFIC CO. / LABORATORY SUPPLIES / APPARATUS CHEMICALS / CHICAGO, U. S. A.
Inscribedon one side of magnet: N
FunctionThis motor was meant to demonstrate a homopolar motor. A power source, connected via one of the binding posts (for instance, the black one), would pass an electric current to the hub of the copper disc. The rim of the disc would sit in the mercury-filled trough. Because mercury conducts current, the electricity would run from the hub to the rim to the mercury. The other contact to the power source (the red one) would sit in the mercury. With the circuit closed, and the current flowing, the surrounding U-shaped magnet and its resultant field cause the disc to rotate.
ProvenanceFrom Science Center Lecture Room, formerly from Allston Burr 11/10/79.