LEROY SOMER 11 KV ALTERNATOR LS54A

DEAR MEMBERS,

I HAVE SIMILARPROBLEM WITH MY TWO ALTERNATORS IN THE SPAN OF LESS THAN ONE YEAR. THAT IS , EXCITATION VOLTAGE INCREASES WITH D.E BEARING TEPERATURE. ONE PIECE WAS REPLACED WITH ANOTHER BRAND OF ALTERNATOR WITHOUT ANY INVESTIGATION IN WARRANTY. WHILE SECOND ALTERNATOR WAS DISMENTLED / INVESTIGATED & FOUND ONE POLE OF MAIN ROTOR WAS EARTHED, EXCITOR ROTOR ONE COIL WAS SHOWING SHORTED & N.D.E BEARING HOUSING WAS WORN OUT AT THE BOTTOM ( ONE mm ).

DEFECTIVE POLE & THE COIL WERE REWOUND WITH SAME SPECIFICATION OF CONDUCTORS & BEARING HOUSING WAS SIZED TO ORIGNAL WITH NEW BEARINGS. ALTERNATOR ALL WINDINGS INSULATION WITH GROUND IS NEAR INFINITY, AND THEIR RESISTANCE VALUES ARE ALMOST SAME AS IN MANUFACTURER,S MANUAL ........ BUT

STILL UPON RUNNING EXCITATION VOTAGE IS 25 V DC AT NO LOAD, WITH INCREASE IN BEARING TEMPERATURES, WHICH IS V. V HIGH COMPARING WITH OTHER GENERATOR . ( SUPPOSED TO BE 12 V ONLY )

WOULD YOU PLEASE COMENT ON THIS ISSUE & SINCERELY GUIDE ME TO RECTIFY THIS PROBLEM .

THANKS

ARSHAD MAHMOOD

ASSIST GENERAL MANAGER( POWER)