3B SCIENTIFIC PHYSICS 1017801 Manual De Instrucciones página 5

3B SCIENTIFIC ® PHYSICS
Electromotor and Generator, Complete 1017801
Instruction manual
01/14 TL/ALF
1 Magnet
2 Armature shaft
3 Left-hand bearing support
4 Armature coil
5 Slip ring
6 Commutator
7 Attachment for current collectors (left: AC, right: DC)
1. Safety instructions
The magnet is not attached to the base plate but
remains loose, so there is a risk of it falling.
Caution: Certain unauthorised operating condi-
tions (excess voltage, supply of current when sta-
tionary) could cause the armature winding to get
hot.

Stay within the permitted operating parame-
ters.
2. Description
The equipment is a working model to demonstrate
the basic operating principle of electric motors and
generators. The simple and easily understood de-
sign closely mirrors the fundamental principle. The
commutator, slip rings for AC operation and the ar-
mature coil are all located on the armature shaft.
8 Current collectors
9 Right-hand bearing support
10 Connector sockets for current collectors
11 Drive pulley / hand crank
12 Leaf springs for current collectors
13 Carbon brushes
The commutator and current collectors change the
polarity of the armature coil after each half turn of
the armature shaft. As the armature coil passes
through a vertical position aligned along the mag-
netic field, the polarity of the coil changes in such
a way that its north pole N is adjacent to the north
pole of the magnet and its south pole is opposite
the magnet's south. The momentum of the coil
causes it to move past this point and the repulsive
force of the like poles then exert a torque on the
coil. Once the armature coil moves past the hori-
zontal position, attractive forces between the mag-
net and the rotor then become increasingly domi-
nant.
When set up as a DC generator, the model outputs
a sinusoidal half-wave signal (pulsating DC). The
polarity depends on the position of the magnet and
the direction of rotation.
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