FR2697656A1 - Electromagnetic force measurement appts. - uses coil sliding on vertical iron core against action of spiral control spring. - Google Patents

Abstract

The appts includes a soft iron core (1) in the form of a long vertical rod fixed to one or more annular permanent magnets (3). A coil is mounted on a bobbin (6) fitting over the iron core (1) and able to slide along it. The bobbin is restrained by a spiral spring (7) which returns the bobbin to the base of the core. Flexible leads allow the connection of electric current to the coil. Graduations on the core allow measurement of the movement of the coil along the core. USE/ADVANTAGE - For studying electromagnetism, such as practical experimental electromagnetism. Exhibits simple demonstration and measurement of electromagnetic fields and forces.

Description

The present invention relates to devices used for
studying electromagnetic phenomena.
current, Cotton scale type require intensity
significant on the order of 1 amp; they are also subject to
an instability which makes their use difficult.

 the device according to the invention makes it possible to avoid these drawbacks, it also offers possibilities of adaptation for simply testing the relevant parameters: length of wire, variation of field, variation of intensity.

 It consists of a long bar of soft iron, one end of which ends in a cylindrical base capable of receiving annular magnets. A coil of copper wire can slide on it, it is introduced on the rod of soft iron by the second end. We feed it by two flexible wires in direct current, the intensity can vary thanks to a suitable device. Depending on the arrangement of the magnets or the connection of the coil> there is attraction or repulsion.

 To return the coil to its initial position, you can use either an adjusted bronze spring guided by the soft iron rod and moving opposite a graduation, or marked brass masses placed in a cup sliding along the rod. , the spring having then been removed.

 The reference zero is identified either visually or by closing an auxiliary circuit by the coil which triggers the ignition of a warning lamp.

 By way of illustration, the perspective drawing is intended to represent the invention.

As shown, the device has a long soft iron rod (l), ending in a base of the same metal (2). On this latter, ferrite type annular magnets (3 ) stacked in any number. Two metallic strips (4 and 5) glued to one of the magnets play with the metallic lower base of the coil (6) the role of switch in an auxiliary circuit connected in (4 and 5); they also serve as stops
The coil supplied with direct current by two flexible wires is brought back into the reference zone by the action of a spring (7) which can be compressed manually by its upper part. the reading of the intensity of the force taking place on a scale (8) carried by the soft iron rod.

 The device 1 according to the invention is particularly intended to be used for experimental manipulations of electromagnetism.

Claims (4)

 ending with a base (2), capable of receiving annular magnets (3). Slats (4 and 5) serve as stops and switches in an auxiliary circuit with the coil (6), which slides on the core  characterized in that it has a long soft iron core (l),  1) The apparatus for the study of electromagnetic forces is  2) Device according to claim 1 characterized in that  that the soft iron rod receives at one end of the magnets on its  base and a coil of copper wire at the other end.  3) Device according to one of claims 1 and 2 characterized PGZT  the fact that the coil can be returned to its reference position  by a spring (7) which, thanks to a scale (8), makes it possible to read 1 '  intensity of the force exerted on the coil.  4) Device according to one of the preceding claims, characterized in that, the coil can be brought back to its reference position, thanks to marked masses placed on a cup sliding along the rod (1)