Does the amount of wire wrapped around a DC motor armature affect its performance?

Answer 1

In short form, yes.

Remember, the stationary field windings (wound on "poles" that are mounted on the stator frame) create a magnetic field that induces a current in the armature winding. This current is proportional to the number of times a wire crosses the magnetic field...

If the amount of "turns" of copper is high, there's likely to be a large resistance to the winding, leading to excessive heat generation and higher losses. "Right sizing" the copper with minimum cross-section and minimum turns gives much better thermal performance.

Also recall that the wire must be at right angles to the magnetic path. Its direction of travel must ALSO be at right angles to the magnetic path (AND at right angles to the wire direction). ... This is known as the "right hand rule". If you've simply wound the armature without regard to this criteria, it's pretty much useless.

What this means in normal manufacture is that the coils run lengthwise, parallel to the shaft. Rotation is ... well ... rotation (tangential to the shaft), and the magnetic field generated by the stationary poles is radial to the shaft.

Answer 2

Yup, increases torque.