The
structure of the brushless AC synchronous generator is divided into two parts,
a stationary part and a rotating part. The stationary part is called a stator,
and includes a base, a stator core, a stator winding, an end cover, a bearing
cover, and a stator of an AC exciter.
Stator
It consists
of a base, a stator core and a stator winding. The stator core and the stator
winding are part of the induced potential and current, which is also called the
armature.
1. Base: The
overall support of the generator, used to fix the armature and the front and
rear end caps together to support the rotor. There are generally outlet boxes
on the base, located on the upper part of the base, and only on the right side
(from the extended end of the shaft). A wiring board is installed in the outlet
box to draw an alternating current or the like.
2. Stator
core: part of the stator iron core generator magnetic circuit. In order to
reduce the eddy current loss, the core is formed by laminating silicon steel
sheets coated with insulating varnish on both sides. The core is provided with
a uniform stepped slot to embed the discharge pivot winding.
3. Stator
winding: consists of coil windings, which are connected in a certain way and
embedded in the core slot. The three-phase windings should be placed
symmetrically and shy at 1200 electrical angles to each other.
End cap
Since the
end cap and the base are used to support the rotor, a bearing bore should be
opened at the center of the end cap for mounting the bearing. The end face of
the end cover has a stop and the base, and the diesel engine is equipped with a
generator on both ends of the shaft extending end cover, and has end stops to
ensure the coaxiality of the rotor after assembly.
AC exciter
stator
The
alternating current generated by the AC exciter is rectified by a rotary
rectifier for excitation by a synchronous generator. In order to avoid
excitation currents for the exciter and the rotating pole generator brush and
the slip ring, the stator of the AC exciter is a magnetic pole, and the rotor
is an armature.
Structure of
rotating part of brushless of AC synchronous generator
The rotating
part of the generator is called the rotor. It includes rotor core, pole
winding, rotating shaft, fan, AC excitation electomechanical pivot and rotary
rectifier.
1. Rotor
core
There are
usually separated salient, integral salient, and hidden pole rotors.
2. Rotating
shaft
At the shaft
end of the generator, the shaft is coupled to the diesel engine through a
coupling on the shaft. It is a key part of converting mechanical energy into
electrical energy, and therefore must have high mechanical strength and
rigidity.
3. Bearing
The
generator adopts two supporting type, that is, bearings are installed at both
ends of the rotating shaft. According to the force, the drive end uses roller
bearings, and the non-drive end uses ball bearings.
4. Fan
When the
generator is running, it will generate various losses and cause heat to be
radiated, so the generator shaft is equipped with a fan for ventilation
cooling. In order to improve the ventilation efficiency, a backward tilting
centrifugal fan is installed in the driving end cover. In this way, during the
operation of the generator, the cold air enters the interior of the generator
from the non-drive end cover and the two sides of the base, adsorbing the heat
of the armature winding, the pole winding, the stator and the rotor core, and
then passing through the drive end cover. The window hole discharges hot air
out of the machine to ensure that the temperature rise of the generator is
within the allowable range.
5. Armature
of AC exciter
In the
brushless synchronous generator, the alternating current generated by the
armature of the AC exciter is rectified by the rotary rectifier to become
direct current for excitation by the alternator.
6. Rotary
rectifier
The rotary
rectifier is a device that rotates coaxially with the AC exciter.
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