METHOD FOR BRAZING ROTOR BARS TO END RINGS OF A ROTOR FOR AN ASYNCHRONOUS AC MOTOR

摘要

A method for brazing end rings to rotor bars for a squirrel cage rotor assembly comprises assembling the rotor in a brazing fixture with a braze shim between the rotor bars and the end rings; preheating the rotor and brazing fixture to a temperature that is below the aged temperature of the rotor bars and end rings and which is sufficiently high so that the difference in thermal expansion of the rotor bars and brazing fixture applies a predetermined amount of pressure on the brazing joint such that after the joint is brazed and has cooled, a braze filler having a predetermined thickness inches will bond the rotor bar end faces to the end ring, and brazing each joint to bond the rotor bar end faces to the end ring. A braze fixture for maintaining a predetermined pressure on a squirrel cage rotor assembly during the process of brazing rotor bars to end rings to form a brazed joint, which rotor assembly includes rotor bars disposed in a rotor core and having their ends positioned on braze shims on end rings, comprises positioning means for positioning the rotor assembly in the apparatus; pressure means for applying a predetermined amount of pressure on the end rings, rotor bars and braze shims of the rotor assembly so that when the ends of the rotor bars, braze shims and end rings are brazed to form a joint, the resulting brazed joint has a predetermined thickness.