QUESTIONS ON THE DEVELOPMENT OF UNIVERSAL BALANCING EQUIPMENT,

Balancing machines MDB-1A, MDU-2, MDU-3 and MDU-210 for aeronautical rotors and balancing machines MDBG-1 and UUG-3 for gyroscope rotors are described. MDB-1A two movable supports for balancing rotors of 15-100 kg. Electronic frequency pickup to 10-15cps consists of a line filter in a special circuit. MDU-2 built in 1952, was the first machine using stationary supports to pick up unbalanced forces with piezoelectric pickups. Rotors 5-100 kg. A light beam reflected from the rotor onto a photocell and an electronic measuring system serve as the unbalance pickup. MDU-3 same MDU-2 for rotors of 5-500 kg but difficulties encountered with rotors above 100 kg led to development of MDU-210 which has stationary support, rotors 10-1000 kg. Electronic measuring devices permit balancing of above rotors within 1-10 gm-cm. Maximum rotor diameter 1400 mm, speed 800 and 450 RPM. MDBG-1 for gyroscope rotor balancing. Has mechanical frequency isolation with optical pickup and secondary vibration system for better sensitivity. No indication of exact place of unbalance. UUG-3 built in 1952 for gyroscope rotor balancing. Has mechano-optical system ofr picking up amount and place of unbalance. Uses mirrors on secondary vibration systems that rotate mirrors which project light beam reflected from rotor on a screen. Diameter of light circle indicates size, location of blank rotor marking indicates place of unbalance. Author