Generator sets offer different options to providing power to the automatic voltage regulator. There are multiple options available for excitation systems and each has its own unique features that provide benefits for different applications. This is generally driven by the electrical characteristics of the load and the short circuit performance requirements. To put it simply the exciter stator is a field that induces voltage in the exciter rotor. It is typically powered by the regulator and is made up of random wound coils in a laminated steel core.
Different excitation methods
The shunt (self excited) excitation uses the output of the main stator to derive power for the input to the AVR. The same output is used for sensing the alternator output to continue properly regulating the voltage required for the input of the exciter. The Excitation Boost System follows the same setup as the shunt excitation for voltage sensing and power input to the automatic voltage regulator but also includes an excitation boost control module and small excitation boost generator added to the non-drive end of the alternator shaft. This is engaged by the AVR when needed normally during generator start up. The PMG system places an additional small permanent magnet generator at the end of the alternator. It is isolated from the disturbances on the main output and produces a clean, uninterrupted 3 phase waveform thereby preventing any disturbances to the input power of the AVR.
Benefits of the exciter stator
The exciter stator is made to be used with the exciter rotor. The unit is smaller than the main stator and is easily replaced. Over time all stators experience certain wear and the heat that is generated can sometimes lead to the varnish that insulates the coils, perishing. This will cause a short and the stator may show signs of excessive heat in a section of the coils. Unless it is a very large stator it is often far cheaper to buy a new one. Winding of a tiny stator would be prohibitously expensive. To order a SPLD 004 Exciter stator, contact Generator Parts to today.