Brushless Exciters

[Freshsurfer]

Hi, I´m trying to find some information about brushless exciters for synchronous motors, I´m working with a 10 MW synchronous motor, I´d like to know how the brushless exciter works, if any know where I can download some explanation of this, I will be grateful

 

[electricpete]

You have a small permanant magnet generator feeding the field of the main generator. The magnets are stationary and create the field. The armature windings are on the rotor and due to relative motion an ac voltage is induced in them... that ac voltage is fed through rotor-mounted rectifier diodes to feed the main field windings.

Everything from PMG armature through main generator field windings are rotating => no need for slip rings to transfer current between rotating and stationary parts.

 

[ScottyUK]

In addition to the scheme described by electricpete, it is fairly common for the PMG to be replaced by a static rectifier controlling the DC field of the exciter.