Diesel generator excitation system have several kinds, each have their own characteristics, different types of different brands of diesel generator excitation system is different also, some choose ac excitation, others is to choose the dc excitation.Below LIXISE will focus on introduce diesel generator excitation system of ac exciter excitation method.

Ac exciter excitation method using coaxial with the master of the alternator as ac excitation power supply.Ac exciter is a small capacity of synchronous generator, this kind of excitation system, the synchronous generator excitation power supplied by ac exciter.Ac exciter issued an alternating current through the silicon diode or thyristor rectifier, supply synchronous generator excitation winding excitation current.This kind of excitation system with ac excitation power supply from other independent outside of the host power supply, so also known as he excitation rectifier excitation system (including separately excited silicon rectifier excitation system and his LiJing thyratron rectifier excitation system), hereinafter referred to as he excitation system.Used as excitation source of coaxial alternator is called ac exciter (also called coaxial auxiliary generator).

This kind of excitation system, according to the static or rotating rectifier, and the ac exciter is a rotating magnetic field or the armature rotation is different, and can be divided into the following four kinds of excitation ways:

(1) ac exciter (rotary magnetic field) and static silicon rectifier;

(2) ac exciter add static thyristor (rotary magnetic field);

(3) ac exciter (armature rotating) and rotating silicon rectifier;

(4) ac exciter (armature rotating) plus rotation thyristor.

(3), (4) two ways above, silicon rectifier element and ac excitation electromechanical pivot with spindle rotation, directly to the host rotor field winding for excitation current, not only cancel the commutator of the dc exciter system - brush structure, and cancelled with the synchronous generator excitation winding is connected to the collector ring - brush structure, so called brushless excitation (also known as non-contact excitation or rotate semiconductor field).Ac exciter excitation winding is fixed.Some generator set a no excitation on the stator winding of magnetic pole, it is made from high quality permanent magnetic material, as the initial magnetic field excitation to build pressure, this is the small unit commonly used a kind of connection mode.

Brushless excitation due to cancelled the slip ring, brush, eliminating the electrical sliding contact of the failure of the most easily, thus greatly improving the operation reliability, and to significantly reduce the maintenance work, at the same time, the whole machine is small in size, the total length shorter.Therefore, it is one of the developing direction of excitation system.At this stage there is a big part of the diesel generator set using the brushless excitation system.

The above (1), (2) two ways for ac excitation electrical pivot and motionless, rectifier ac exciter polarity rotating excitation mode, rarely used in diesel generator set.