3 phase synchronous generator or motor require DC current in the rotor. Conventional way of supplying DC requires use of commutators, which requires timely maintenance. To overcome this Brush less Excitation systems is used.
Brushless Escitation system consists of one pilot excitor - DC generator with rotating PM as the field and the armature as the stator. The armature of the pilot excitor is connected to the stator of main excitor which is a 3-phase synchronous generator (please do not get confused, this is not our alternator but the exciter for the alternator). The rotor of the main exciter is connected to a diode bridge to get DC. This is connected to the rotor of our alternator.
Draw the brushless excitation scheme of alternation?
The rotor excitation circuit
A brushless system for R/C cars is a engine system without brushes. No brushes equals faster car. brushes equal slower car.
The reverse KVAR relay protects a generator from a loss of excitation. When the excitation system is lost, reactive power will flow from the system back into the generator. When this happens, induced currents at twice the system frequency will flow in the rotor windings and rotor structure.
Brushless are 10x more powerful than brushed and use 3 wires instead of 2. And most brushless motors are outrunners, meaning the spinning part is outside not inside.
Zillman's Excitation Transfer Effect http://doctordigger.blogspot.com/2005/07/zillmans-excitation-transfer-effect.html
Hi, Under excitation - inductive reactive power Over excitation - Capacitive reactive power.
It is called static excitation when you make use of solid state components like diode and thyristors to convert to pure dc and to use this dc for field excitation of synchronous generators. The field winding of synchronous generators can be excited by dc source only. It is called brushless excitation because use of carbon brushes are not made here.It is called dynamic excitation is when you make use of rotating brushes. Excitation is necessary to produce reactive power and also to regulate the voltage of synchronous generators.
A brushless system for R/C cars is a engine system without brushes. No brushes equals faster car. brushes equal slower car.
Castle 4600 sidewinder
Over Excitation is a condition when the Excitation System is providing too much field current and as a result, the rotor of the generator will over heat. The Excitation System is equipped with an Over Excitation Limiter. This limiter acts to reduce the Excitation Current if this condition exists Underexcitation is a condition when the generator is not getting enough Excitation Current. If the generator does not get enough Excitation Current, it can be un-synchronized with the grid. We call this slipping a pole. If this occurs, the generator can be severely damaged. Kelly Thompson Engineering Lead Siemens Energy Alpharetta GA
A variable that causes change in the output of a system. In a RC circuit, for example, the input V is the excitation variable
stickier tires and a very powerful 550 brushless system.
when excitation fails,Reactive power will be supplied by the system to which the generator is connected and generator will work as induction generator and its speed will rise a little. generator which was in over excitation mode will work in underexcitation.but there is under excitation limit which should not be reached so we should detect loss of excitation and trip generator
static type thyristor controlled excitation system
The reverse KVAR relay protects a generator from a loss of excitation. When the excitation system is lost, reactive power will flow from the system back into the generator. When this happens, induced currents at twice the system frequency will flow in the rotor windings and rotor structure.
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The body tissue that transmits waves of excitation is nervous tissue. This type of tissue is found in the nervous system and it is made up of neurons.
Brushless Painting - 2013 was released on: USA: November 2013