ELECTRIC MACHINES

Elgi Electric & Industries Ltd manufactures alternators in technical collaboration with Guinault France. There was 20kVA to 380kVA Alternators available. Now Elgi Electric has stopped production of Alternators and they are more concentrating in AC Motors and DC Motors. Sara Elgi is a group of companies from Textiles, Software, Building etc. The following figure shows a schematic diagram of Elgi Electric make Alternator. There are five windings in Elgi alternators. Exciter Field, Exciter Armature, Main Field, Main Armature, Auxiliary Winding. The Auxiliary Winding is wound over the Main Armature (Stator). This winding gives 40V, 6A AC supply for AVR. Exciter Field is also fitted with Permanent Magnets. This will avoid break down of alternator due to loss of residual magnetism. Due to the permanent magnets there will be around 100V output between phase without AVR. If alternator does not produce 80 to 100V at rated speed with out AVR we can suspect any internal fault with the alte...

  The above diagram shown connection of Kirloskar AVR model KAVR-1. This type of AVR is used in some brush-less alternators manufactured by Kirloskar Electric Company Ltd . This is a single phase sensing AVR. Sensing voltage and working voltage are taken from the main armature (output supply) of the alternator. This is not recommended for unbalanced load. As the AVR is is sensing only the voltage of one phase regulation will not be proper for unbalanced load. Most of the AVR are two phase sensing were as there are some three phase sensing AVR also available. This AVR was used in smaller alternators. Now it is replaced with KAVR-2 which is two phase sensing. This AVR has 3 multy tern potentiometers that are used to adjust the output voltage (P1) Under frequency cut-off (frequency roll off) (P2) and Voltage Stability (P3) By Adjusting P1 clockwise we can increase the output voltage and counterclockwise adjustment of P1 will decrease the output voltage.  AVR is supposed to main...