| Electrical machines include AC and DC motors, generators and alternators. This group of machines can be considered the most commonly used driving machine in industry.
Vibration problems in electrical machines can be divided mainly into those having
- a mechanical origin or
- an electrical origin In this group of machines, mechanical faults, which may cause vibration problems of their own, very often also lead to electrical vibrations, such as a rotor eccentric to the stator, cracked or broken rotor bars or end rings, bad joints between rotor bars and end rings, open or short-circuited windings, and others. The resultant electrical vibrations may have frequencies very close to the mechanical vibration frequencies, or their harmonics. Analysis and accurate diagnosis in such cases requires the use of high-resolution analysers, with a tracking filter capability to discriminate between mechanical and electrical vibrations. Electrical machines can normally be efficiently and adequately protected against damage using a portable data-collector and PM software program. | | |
