AC Power vs. Field Current of a DC Generator: Explained

In summary, the attached image shows a curve of AC Power vs. Field Current of a DC Generator. This curve represents the power required to generate a stronger field current, which in turn requires more mechanical power from the prime mover. The speed is kept constant, and the open circuit power (Poc) represents the electrical power component with no external load on the generator. This could also apply to a self-excited synchronous generator.
  • #1
BuckeyeNut
1
0
I am trying to understand this curve; it is AC Power vs. Field Current of a DC Generator. I am not sure what its significance is? What it's telling me? Can someone please explain it to me? See attached image.

BTW... Pac = AC Power
If = field current
Poc = open circuit power
Prot = rotational power (I believe)

Thanks in advance!
 

Attachments

  • DC Generator Characteristics.jpg
    DC Generator Characteristics.jpg
    24.4 KB · Views: 489
Engineering news on Phys.org
  • #2
Hi BuckeyeNut. :welcome:

It helps if you provide some background to figures, but I'll take a stab. First, devise a fitting scenario...

You have an AC motor turning a self-excited DC generator. As you adjust the setting for a stronger field current you are requiring the generator to produce more current to more strongly magnetise its own stator. Generating this current requires mechanical power, and this drive comes from the prime mover.

The speed is kept constant, meaning rotational losses are fixed, so that component of the load on the prime mover is not varying, it's the increasing power needed for generating the DC for the field that causes the rising curve in the sketch.

The picture may not be of two machines, either. It might just be a self-excited synchronous generator. Poc might be more descriptively labelled as representing the electrical power component with no external load on the generator (open-circuit terminals).

Does this fit the context from which you extracted the figure?
 

What is the difference between AC power and field current of a DC generator?

The main difference between AC power and field current of a DC generator is the type of current that is produced. AC power refers to alternating current, which changes direction periodically, while field current of a DC generator refers to direct current, which flows in only one direction.

How do AC power and field current affect the performance of a DC generator?

AC power and field current both play important roles in the operation of a DC generator. AC power is used to create a magnetic field within the generator, while field current helps to control the strength of this magnetic field. This ultimately determines the amount of power that the generator can produce.

Why is AC power used to create the magnetic field in a DC generator?

AC power is used to create the magnetic field in a DC generator because it is easier to generate and control compared to DC power. AC power can be easily stepped up or down using transformers, making it more efficient for creating the necessary magnetic field in a DC generator.

What factors can affect the relationship between AC power and field current in a DC generator?

Several factors can affect the relationship between AC power and field current in a DC generator, such as the strength of the magnetic field, the speed of the generator, and the load on the generator. Changes in any of these factors can impact the amount of AC power needed to maintain a constant field current.

Can a DC generator operate without AC power?

No, a DC generator cannot operate without AC power. AC power is necessary to create the initial magnetic field within the generator, which is essential for the generation of electricity. Without AC power, there would be no magnetic field and therefore no power output from the generator.

Similar threads

  • Electrical Engineering
Replies
15
Views
631
Replies
7
Views
1K
  • Electrical Engineering
Replies
8
Views
1K
  • Electrical Engineering
Replies
10
Views
2K
Replies
6
Views
2K
Replies
6
Views
3K
Replies
11
Views
1K
  • Electrical Engineering
Replies
7
Views
206
  • Electrical Engineering
Replies
13
Views
2K
Replies
7
Views
905
Back
Top