load is connected to generators.but where it becomes power? where we can get p.f?

Answer 1

The generator is the source of the power. But as long as no load is connected to it, no power is dissipated, except for some losses in the generator.

PF is a characteristic of the load. It is the cosine of the angle between the current and the voltage. If the load is purely resistive, then the current and the voltage will be in phase, the angle between them will be zero, and the power factor will be 1. If there is either some net reactance, such as either inductance or capacitance across the load, it will induce a phase shift between the voltage and the current, and the power factor will fall to some value less than 1.

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Answer 2

The question really needs to asked in a different way. I'm not sure what tthe quest is, but here gose.

An electric moter and a generator are really the same thing.
Anyway, a generator that does not contain any permanent magnets but instead uses field coils requires a current flow to be present in the field coils for the generator to be able to produce any power at all. If the field coils are not powered, the rotor can spin without the generator producing any usable electrical energy.

For older and very large power generating equipment, it has been traditionally necessary for a small separate exciter generator to be operated in conjunction with the main power generator. This is a small permanent-magnet generator which produces the current flow necessary for the larger generator to function.

Most modern generators with field coils feature a capability known as self-excitation where some of the power output from the rotor is diverted to power the field coils. Additionally the rotor or stator contains a small amount of magnetizable metal, which retains a very weak residual magnetism when the generator is turned off. The generator is turned on with no load connected, and the initial weak field creates a weak flow in the field coils, which in turn begins to slightly affect the rotor to begin to produce current that then further strengthens the field. This feedback loop continues to increase field voltage and output power until the generator reaches its full operating output level.

This initial self-excitation feedback process does not work if the generator is started connected to a load, as the load will quickly dissipate the slight power production of the initial field buildup process.

It is additionally possible for a self-exciting generator either turned off or started with a load connected to result in dissipation of the residual magnetic field, resulting in complete non-function of the generator. In the case of a 220v portable generator commonly used by consumers and construction contractors, this loss of the residual field can usually be remedied by shutting down the generator, disconnecting all loads, and connecting what are normally the high-voltage/amperage generator outputs to the terminals of a common 9-volt battery. This very small current flow from the battery (in comparison with normal generator output) is enough to restore the residual self-exciting magnetic field. Usually only a moment of current flow, just briefly touching across the battery terminals, is enough to restore the field.

Answer 3

It is difficult for me to understand your question. I will try to respond with a minimum of electrical theory and math.

Power is the rate of flow of energy. One watt of power is one joule per second of energy flowing from one place to another or being converted from one form to another. A generator typically receives mechanical energy from a turbine through a turning shaft, converts that energy to electrical as voltage driving current through wires and through the load. If there is no load connected, there can be voltage, but no current, so no power flows. If there is no current, the generator is not converting any mechanical energy to electrical energy. It is not taking any energy from the turbine. The generator shaft turns with very little effort.

The power factor is the power used by the load divided by the total apparent power in the electrical circuit. The total apparent power includes the power used by the load plus power that circulates back and forth between the generator and energy storage elements in the load. Energy is stored in the load mostly in the magnetic fields that are required for the operation of electric motors. Electric motors and generators are fundamentally the same machine operated in two different ways. Generators also have magnetic fields that can store energy. The circulating part of the power represents energy stored in the load during one instant in time and stored in the generator during the next instant.

Answer 4

Since amperage is what we can measure,
with a simple ammeter, we generally work in KVA.
with generators.
KW. may become apparent in the fuel consumption
figures for the generators.
To get the power factor, you need a Wattmeter to
compare readings with the ammeter figures, (multiplied by the voltage supplied).

Answer 5

if by pf you mean power factor its simply power used by system loads (alternatively you can figure that out by total power produced minus reactive loading) divided by total power produced. if you set it up as a triangle:

horizontal line: power used by system loads
verticle line: reactive power
hyponenus (sp?): total power produced

taking the cos of the angle between the horizontal line and the hypot also gives the power factor