Why are DC generator loops wired in a non-traditional manner?

In summary, the conversation discusses the analysis of a simple DC generator with a single loop in the presence of a magnetic field. It then extends to a second loop, resulting in a more regular supply of pulses at the brushes. The two coils are connected to a commutator in a straightforward manner. However, in real life, generators with multiple loops are wired differently, with opposite ends of a loop connected at non-opposite points on the commutator. The speaker asks for assistance in understanding the reasoning behind this and how it affects the voltage generated.
  • #1
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Given a simple DC generator with a single loop in the presence of a magnetic field such as the one below, typically, the analysis involves how each rectangular loop's terminal ends up on opposite sides of an armature housing each of the coils.
fig4fwd.gif
The analysis is fairly straightforward to then extend to a second loop positioned perpendicular to the first loop. The result is also a rectified / pulsed DC waveform at the brushes, except there will be a more regular supply of pulses than in the case with one loop. The two coils are connected to a commutator such that opposite ends of each loop's terminals go to opposite ends of the commutator. This is conceptually straightforward as well.

All of this is fine, but in real life, generators with many such armature windings / loops are wired such that the opposite ends of a loop are connected as follows.
commutator.jpg
In other words, given 6 loops, instead of the first loop having one end at 12 o'clock on a clock and the other end at 6 o'clock on a clock, the ends are at 12 o'clock and 1 o'clock. Can someone help me understand why? How does the analysis change, if at all at that point, as far as how much voltage is generated?

Thanks in advanced.
 
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  • #2
The relevant lecture that shows the origin of the confusion: starting at around 18-20.
 

1. What is a DC generator and how does it work?

A DC generator is a type of electrical machine that converts mechanical energy into electrical energy. It works by using a rotating coil of wire, called an armature, within a fixed magnetic field. As the armature rotates, it cuts through the magnetic field, creating an electric current.

2. What are the basic components of a DC generator?

The basic components of a DC generator include the armature, field poles, commutator, brushes, and a DC power source. The armature is a rotating coil of wire, the field poles create the magnetic field, the commutator changes the direction of current flow, the brushes make contact with the commutator, and the DC power source provides the energy to rotate the armature.

3. How do you wire a DC generator to a battery?

To wire a DC generator to a battery, connect one end of the field winding to the positive terminal of the battery and the other end to the negative terminal. Then, connect the positive terminal of the armature to the positive terminal of the battery and the negative terminal of the armature to the negative terminal of the battery. Lastly, connect the field winding to the commutator and the brushes to the commutator.

4. What is the purpose of the commutator in a DC generator?

The commutator in a DC generator is responsible for changing the direction of current flow in the armature. As the armature rotates, the commutator switches the connections between the armature and the external circuit, ensuring that the current flows in one direction.

5. How do you determine the polarity of a DC generator?

The polarity of a DC generator can be determined by the direction of current flow in the armature. If the current flows from the positive terminal to the negative terminal, the generator is said to have positive polarity. If the current flows from the negative terminal to the positive terminal, the generator has negative polarity.

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