scope:

Scope of application

The present Part 5 of the guideline VDI 3839 gives an overview of the typical vibration patterns encountered in electrical machines with outputs between 10 kW and a few hundreds of MW. These machines may be three-phase alternating current generators or direct-current generators installed in thermal power stations, or small hydro-electric power plants, in vehicles or aboard ship. The majority of machines in this power range are synchronous, asynchronous or d.c. motors in service as drives in the mining and metallurgical industry, in the chemical or petrochemical industry and in process engineering. This group also includes drives for machine tools, ships and rail vehicles. While three-phase alternating current generators in thermal power stations predominantly run at nominal operating speeds of 3000 min-1 or 3600 min^-1, direct-current generators and all types of motor can have rated or operating speeds ranging between just a few revolutions per minute and 12 000 min^-1. Speeds in the lower and higher parts of this range are frequently encountered in large d.c. motors and a.c. motors which are supplied by power converters. The electrical machines with which Part 5 is concerned are frequently connected via flexible couplings to the driving or driven machine and may stand on relatively elastic foundations or structures.

VDI 3839 Part 5 does not provide information about the special vibration patterns of turbine-driven generators with hydrogen cooling or water-cooled stator and rotor windings. Generators or motors in service in large hydro-electric power plants will be treated in Part 6 since the rigid coupling of the shafting and the great influence of the machine's physical installation make separation between the hydraulic and the electrical machines inadvisable. The same applies to electrical machines which are rigidly coupled to reciprocating machines (motors or compressors). They will be dealt with in Part 8.