alternating current motor demonstration (?)
Date: ca. 1910-1940
Inventory Number: RS0805
Classification: Demonstration Apparatus
Subject:
Maker: Central Scientific Company (1889 - 2000)
User: Cruft Laboratory, Harvard University (founded 1914)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
20 x 80 x 23 cm (7 7/8 x 31 1/2 x 9 1/16 in.)
Description:
A rectangular wooden board with three distinct electrical devices mounted on it.
At each end of the board is a motor arrangement, with several coils mounted inside a horizontal black metal ring around a rotating section in the middle. The two motors are identical except the one on the left has six coils (red, yellow and green), whereas the one on the right only four coils (red and green).
Between the two motors is a different arrangement that appears to be a generator or alternator. A vertically mounted wheel with a metal coil all around its outer edge. The wheel can be turned with a hand crank. Several metal strips can be adjusted to make contact with the outer edge as well as two metal contacts (wheels) that connect to different points on on the exterior.
The three devices have numerous binding posts, most unmarked except for two on each side of the generator labelled "battery".
At each end of the board is a motor arrangement, with several coils mounted inside a horizontal black metal ring around a rotating section in the middle. The two motors are identical except the one on the left has six coils (red, yellow and green), whereas the one on the right only four coils (red and green).
Between the two motors is a different arrangement that appears to be a generator or alternator. A vertically mounted wheel with a metal coil all around its outer edge. The wheel can be turned with a hand crank. Several metal strips can be adjusted to make contact with the outer edge as well as two metal contacts (wheels) that connect to different points on on the exterior.
The three devices have numerous binding posts, most unmarked except for two on each side of the generator labelled "battery".
Signedplate on base: plate on front: CENTRAL SCIENTIFIC CO. / TRADE MARK / LABORATORY (CENCO logo) SUPPLIES / APPARATUS CHEMICALS / REG. U.S. PAT. OFF. / CHICAGO, ILL
Inscribedplate on base: BATTERY
FunctionThis appears to be an alternating current (AC) motor demonstration. The devices at both ends of the board are electric motors, and the device in the middle is the AC power source. It appears that one would connect a battery, which gives direct current, to the generator at the center, and turn the wheel to produce the alternating current. Depending on the speed of the central wheel, the motors on the sides would turn at different speeds. The two motors will also turn differently for having a different number of coils.
ProvenanceCruft Laboratory, Harvard University.