How does a simple motor work (in INTENSE detail)?

Question

thanks =]

Answer 1

The copper used in the stator winding is generally rated OFHC for maximum ductility and conductivity. The ductility of OFHC copper for strain rates between 0.1 and 10 s^-1 (typical of stator winding operations) is about 0.25. Faster more modern stator winding machines, however, can often result in significantly higher strain rates, where the ductility of OFHC copper can drop off significantly, so care must be taken. The higher strain rates also lead to increased work hardening due to higher order material strength effects, whose details are beyond the scope of this reply. Normally, this has negligible effect on motor operation, but is correlated with higher resistivity too. This may adversely affect the motor's electrical efficiency, but is considered a reasonable engineering trade-off given the lower production costs entailed.

Continued ...

Answer 2

It is hard to answer this question. When I hear the term 'motor' I think of an electric motor. The distinction between 'engine' and 'motor' is a nuanced one, but I usually take the difference to be that an engine has an internal power source, whereas a motor has an external power source that is used to accomplish work.

That said, an electric motor can be of two basic types depending on the type of electricity used to power it. The first is a DC motor. A DC motor has a few key parts. Magnet, armature, brushes, and a commutator.

An armature is a coil of wires that is free to spin under the influence of a magnetic field. The wires must first have a field induced by a current. When electricity is applied, a current is set up in the wires (this happenes ANY time a current flows). Next there is a clever setup called a commutator. This is a device that allows electrical contact between the spinning armature, and the battery. This is accomplished by having a set of brushes that just touches a metal ring, usually near the axle where the wires are to spin. As well as contact, the commutator is wired up so that when the armature spins, electrical contact is broken and then the direction of the current is reversed. With the current flowing in the opposite direction, the armature will rotate to re-align itself in the magnetic field of the permanent magnets. But just as it gets perfectly aligned again, the direction of the current will change again and the whole cycle repeats.

In an AC motor, the direction of the current changes for us, in the US, it changes 60 times second. The same basic setup is employed in an AC motor as well. There is an armature and instead of a static magnetic field, there is a rotating magnetic field in what is called a 'stator.' Usually multiple phases (the wave crests arrive at different times) are employed in an AC motor. Single phase can be used, but then more complicated circuit arrangements must be devised to achieve the rotating electric field that is required.

In a multi-phase AC motor, the field rotates around the armature, which has a constant current in it. Basically the field in the stator is made to change so that the armature is always 'chasing' it.