In order to control the excitation of the synchronous motor, a Brushless Exciter is used. The circuit of an exciter comprises of a discharge resistor, a rotating transformer which is centre tapped and a field winding. One end of the winding and the one end of rotating transformer are coupled together. The other end of the winding is coupled along with the center tap of the transformer and the end of discharge resistor. The exciter uses four powers SCR. The circuitry of the Brushless Exciter controls the excitation level and the application of field current. The time for application and removal of field is determined by the circuitry by monitoring the frequency, phase angle and presence of discharge current.
There are wide ranges of motors available in the market. Each motor is dedicated for a particular application. Here is a brief discussion on few types of Wound Rotor Motors:
Brushed: The different components of this type of motors are: an armature, split ring commutator and a magnet. The rotor windings are fed the electrical power source with the help of commutator and its neighboring brushes. This magnetizes the core of the rotor temporarily. It is the function on the commutator to see that the magnetic poles of the rotor and that of the stator never aligns with each other. This will ensure the continuous motion of the motor.
Brushless: There are some problems with the brushed design which are being eliminated in the brushless one. An external electronic switch replaces the commutator. These switches work in synchronization with the position of the rotor.
Ironless/Coreless: It is a modified version of the brushless or brush Wound Rotor Motors. It is generally applied to enhance acceleration. The core of the rotor has no iron component in it. The rotor can fit inside the stator magnets taking the form of a self supporting structure or a winding filled cylinder.
Printed Armature/Pancake: Here the windings are disc shaped running between the arrays of a magnet with higher flux density. The magnets are arranged facing the rotor in a circular form. The extremely flat profile is the reason for its name.
Now with a bit of understanding of the above different types of motor, you can easily pick the one that fulfills your requirements. There are some disadvantages of each type as well as advantages too because of which they are still in use.
There are wide ranges of motors available in the market. Each motor is dedicated for a particular application. Here is a brief discussion on few types of Wound Rotor Motors:
Brushed: The different components of this type of motors are: an armature, split ring commutator and a magnet. The rotor windings are fed the electrical power source with the help of commutator and its neighboring brushes. This magnetizes the core of the rotor temporarily. It is the function on the commutator to see that the magnetic poles of the rotor and that of the stator never aligns with each other. This will ensure the continuous motion of the motor.
Brushless: There are some problems with the brushed design which are being eliminated in the brushless one. An external electronic switch replaces the commutator. These switches work in synchronization with the position of the rotor.
Ironless/Coreless: It is a modified version of the brushless or brush Wound Rotor Motors. It is generally applied to enhance acceleration. The core of the rotor has no iron component in it. The rotor can fit inside the stator magnets taking the form of a self supporting structure or a winding filled cylinder.
Printed Armature/Pancake: Here the windings are disc shaped running between the arrays of a magnet with higher flux density. The magnets are arranged facing the rotor in a circular form. The extremely flat profile is the reason for its name.
Now with a bit of understanding of the above different types of motor, you can easily pick the one that fulfills your requirements. There are some disadvantages of each type as well as advantages too because of which they are still in use.
No comments:
Post a Comment