Generators and the associated force?

In summary: Originally posted by WarrenI don't think phillip was asking about the demand side. The generators output a power which depends on the load (because they have an output impedance and there are also other factors). As, I believe, phillip has realized, a higher load means more current, which means a different impedance mismatch. There are two ways to solve the problem: 1) have an adjustable impedance matching network that couples the imput shaft to the electrical output at a constant mechanical impedance, 2) reduce or increase the current requirement for any given generator by simply engaging or disengaging other generators in parallel. There are complications, but, it can be done. The feedback is derived from the same principle
  • #1
philipc
57
0
Question, does the force required to turn a generator change with changing current loads?
Basically I’m wondering if it would take more force to turn a generator when there is a load, apposed to if there were zero load?
Thanks
Philip
 
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  • #2
Originally posted by philipc
Basically I’m wondering if it would take more force to turn a generator when there is a load, apposed to if there were zero load?
Yup, it does. The conservation of energy applies everywhere.

- Warren
 
  • #3
chroot,
Thanks for the quick response,
So could it also be said the only forces on the generator without load(not including friction ect) would be from losses in the generator it self?
In other words an "Ideal" generator would spin indefinitely until there was a current load put on it?
Wow this Physics II stuff is making me go crazy!
Thanks again
Philip
 
  • #4
Originally posted by philipc
chroot,
Thanks for the quick response,
So could it also be said the only forces on the generator without load(not including friction ect) would be from losses in the generator it self?
In other words an "Ideal" generator would spin indefinitely until there was a current load put on it?
Wow this Physics II stuff is making me go crazy!
Thanks again
Philip
Also correct.

- Warren
 
  • #5
Another question, since load effects force, what keeps the generators at 60hz when the load is constantly changing on the power grid.
Philip
 
  • #6
There are usually hundreds of generator that can be turned on and off. If the load reduces for a given number of generators, the frequency goes up. If the load increases frequency goes down. The frequency is used as an indicator to signal generators to turn on and off. Turning on more generators will increase the frequency. Turning off generators will decrease the frequency.
 
  • #7
Originally posted by turin
There are usually hundreds of generator that can be turned on and off. If the load reduces for a given number of generators, the frequency goes up. If the load increases frequency goes down. The frequency is used as an indicator to signal generators to turn on and off. Turning on more generators will increase the frequency. Turning off generators will decrease the frequency.
I think you have it but its a little unclear. Frequency in ac motors/generators is a function of the physical design and rpms. So on the supply side, the rpms are controlled (very precisely as a matter of fact) to regulate the frequency. Its done electronically but I don't know exacly how. On the demand side, the motor always runs at its design rpm (unless it has a variable frequency drive). If you add load to the motor, the amperage will go up and the rpm will stay the same. Obviously, if you overload it, it will fail to maintain the rpm and the power output will drop radically (or you'll just burn out the motor). The supply side is a similar delicate balance as seen recently with cascade power failures in NY and Italy. One little blip can destabilize the whole grid and knock it off line if they are riding the edge of their capacity.
 
  • #8
I don't think phillip was asking about the demand side. The generators output a power which depends on the load (because they have an output impedance and there are also other factors). As, I believe, phillip has realized, a higher load means more current, which means a different impedance mismatch. There are two ways to solve the problem: 1) have an adjustable impedance matching network that couples the imput shaft to the electrical output at a constant mechanical impedance, 2) reduce or increase the current requirement for any given generator by simply engaging or disengaging other generators in parallel. There are complications, but, it can be done. The feedback is derived from the same principle as FM.
 

1. What is a generator?

A generator is a device that converts mechanical energy into electrical energy. It works by rotating a conductor within a magnetic field, creating a flow of electrons that generates an electrical current.

2. How does a generator produce electricity?

A generator produces electricity through the process of electromagnetic induction. This is when a conductor, such as a wire, is moved through a magnetic field, causing a flow of electrons and creating an electrical current.

3. What is the associated force in a generator?

The associated force in a generator is the force exerted on the conductor by the magnetic field. This force is responsible for the movement of the conductor, which in turn creates the flow of electrons and generates electricity.

4. What factors affect the output of a generator?

The output of a generator can be affected by various factors, including the speed at which the conductor is rotated, the strength of the magnetic field, and the size and quality of the conductor. Other factors such as temperature and resistance can also impact the generator's output.

5. What are the different types of generators?

There are various types of generators, including AC generators, DC generators, and synchronous generators. AC generators produce alternating current, while DC generators produce direct current. Synchronous generators are used in power plants to supply electricity to the grid.

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