What is excitation, excitation current, what is the difference between motor and generator
Excitation is the device that provides the rotor power to the rotor of the generator. According to the different methods of dc motor excitation, and can be divided into his field, and excitation, the string of excitation, compound excitation, the process of dc motor rotation, excitation is to control the stator voltage to produce magnetic field changes, change the rotating speed of dc motor, Changing excitation also changes the speed The main effect of excitation is: To maintain the voltage of the generator at the given value, when the generator load is changed, the voltage of the voltage of the voltage of the machine is constant by adjusting the strength of the magnetic field. Reasonable distribution of reactive power distribution between parallel running units. Improve the stability of the power system, including static stability and transient stability and dynamic stability. Types of excitation: The method of rectifier can be divided into rotational excitation and static excitation. The rotary excitation includes dc ac and brushless excitation. The stationary excitation includes the electric potential source stationary exciter and the composite power supply stationary exciter.
The excitation current is provided by the independent power supply for the motor excitation winding. For example, the use of an independent dc power source for the excitation winding of a dc generator; The electromagnetic field of the armature winding of the asynchronous motor is generated by ac power supply. The former is the dc excitation, the latter is the exchange excitation. Synchronous motor according to the situation of the power grid, can be a rotor field winding dc excitation, can also be provided by the grid ac excitation on the stator, the general is given priority to with dc excitation. If the dc excitation is insufficient, then the reactive reactive current from the grid input is added to the motor. If the dc excitation method is overused, the motor will output the backward reactive current to the grid, weakening the internal magnetic field of the motor. When the dc excitation is adopted, the voltage drop in the excitation circuit is only caused by the resistance, the excitation voltage is low, and the excitation power supply is small. With the use of ac excitation, the excitation voltage is much higher, and the capacity of excitation power supply is much higher.
A way of producing a magnetic field in a rotating motor. Most modern motors are based on electromagnetic induction, which requires a magnetic field in the motor. The magnetic field can be generated by a permanent magnet or by an electric magnet in the coil. The coil group that is set up to produce a magnetic field is called the excitation winding. Due to the limitation of the performance of permanent magnet, the magnetic field built by the permanent magnet is weak, which is mainly used for small capacity motors. But with the emergence of new permanent magnet materials, especially high magnetic energy product of rare earth materials such as the emergence of cobalt and rare earth ndfeb, capacity of the kilowatt of permanent magnet motor has started to develop.
As for the previous question, I won't say any more about the previous one. The excitation of the generator is of course the power supply, no power supply cannot excite, the magnetism of the generator is not enough to generate electricity. Electricity is electricity, but the power consumption is very small, and the generator is very big!! This is small investment, big return!
