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• Static balancing : Singe plane is used for the balancing • Dynamic balancing: Two or more planes are used for the balancing. Two plane balancing: For rigid rotors only (ω < ωcr) this method can be used. N-plane balancing: For flexible rotors (ω > ωcr) this method is used. If the shaft deflects, and the deflection and the centrifugal force change with speed, as it does in the vicinity of critical speeds (ω > ωcr). Balancing of Rigid Rotor : Cradle balancing machine: The rotor is placed in the bearings of a cradle as shown in Fig. 1. The cradle is placed on two springs and can be fulcrumed about F1 or F2 to form a simple vibrating system. Two fulcrum can be located at two chosen balance planes (i.e. I and II), where the correction mass to be added. The rotor can be driven by a motor through a belt pulley arrangement. If the spring system is such that the natural frequency of the system is in the range of motor speed, the phase angle or the location of the mass in either plane can be determined as follows. Fulcrum the cradle in plane I by fixing F1 and releasing F2. Run the rotor to resonance, observing the amplitude of vibration to the right of fulcrum F2. This vibration is due to all the unbalance in plane II , since the unbalance in plane I has no moment about F1. Use a trial mass at a chosen location and determine the amplitude of vibration. Construction procedure The Influence Coefficient Method Definition of Influence coefficients : Figure 5 (a) shows that when a force F1 is applied at station 1 and due to this force the beam deflections at stations 1 and 2 are given as y11 = displacement at station 1 due to force F1 at station 1 = and, y21 = displacement at station 2 due to force F1 at station1 = where is the influence coefficient and its first subscript represents the displacement station and second represents the force station. Similarly for Figure 5 (b), we have In Figure 5(c), we have Influence coefficients can be obtained by experimentation or by strength of materials formulae i.e. Services: - Field Balancing of Rotors Homework | Field Balancing of Rotors Homework Help | Field Balancing of Rotors Homework Help Services | Live Field Balancing of Rotors Homework Help | Field Balancing of Rotors Homework Tutors | Online Field Balancing of Rotors Homework Help | Field Balancing of Rotors Tutors | Online Field Balancing of Rotors Tutors | Field Balancing of Rotors Homework Services | Field Balancing of Rotors
• Static balancing : Singe plane is used for the balancing • Dynamic balancing: Two or more planes are used for the balancing. Two plane balancing: For rigid rotors only (ω < ωcr) this method can be used. N-plane balancing: For flexible rotors (ω > ωcr) this method is used. If the shaft deflects, and the deflection and the centrifugal force change with speed, as it does in the vicinity of critical speeds (ω > ωcr). Balancing of Rigid Rotor : Cradle balancing machine: The rotor is placed in the bearings of a cradle as shown in Fig. 1.
The cradle is placed on two springs and can be fulcrumed about F1 or F2 to form a simple vibrating system. Two fulcrum can be located at two chosen balance planes (i.e. I and II), where the correction mass to be added. The rotor can be driven by a motor through a belt pulley arrangement. If the spring system is such that the natural frequency of the system is in the range of motor speed, the phase angle or the location of the mass in either plane can be determined as follows. Fulcrum the cradle in plane I by fixing F1 and releasing F2. Run the rotor to resonance, observing the amplitude of vibration to the right of fulcrum F2. This vibration is due to all the unbalance in plane II , since the unbalance in plane I has no moment about F1. Use a trial mass at a chosen location and determine the amplitude of vibration.
Construction procedure The Influence Coefficient Method Definition of Influence coefficients : Figure 5 (a) shows that when a force F1 is applied at station 1 and due to this force the beam deflections at stations 1 and 2 are given as y11 = displacement at station 1 due to force F1 at station 1 = and, y21 = displacement at station 2 due to force F1 at station1 = where is the influence coefficient and its first subscript represents the displacement station and second represents the force station. Similarly for Figure 5 (b), we have In Figure 5(c), we have Influence coefficients can be obtained by experimentation or by strength of materials formulae i.e.
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