This part of IEC 61800 specifies requirements for adjustable speed power drive systems, or their elements, with respect to electrical, thermal and energy safety considerations. It does not cover the driven equipment except for interface requirements. It applies to adjustable speed electric drive systems which include the power conversion, drive control, and motor or motors. Excluded are traction and electric vehicle drives. It applies to d.c. drive systems connected to line voltages up to 1 kV a.c, 50 Hz or 60 Hz and a.c. drive systems with converter input or output voltages up to 35 kV, 50 Hz or 60 Hz.Rating specifications for d.c. power drive systems connected to line voltages up to 1 kV a.c. are covered in IEC 61800-1. Rating specifications for a.c. power drive systems with converter input or output voltages up to 1 kV a.c. are covered in IEC 61800-2. EMC aspects are covered in IEC 61800-3. Rating specifications for a.c. power drive systems with converter input or output voltages greater than 1 kV a.c. and up to 35 kV a.c. are covered in IEC 61800-4. The scope of this part of IEC 61800 does not include devices used as component parts of a PDS if they comply with the safety requirements of a relevant product standard for the same environment. NOTE 1 In some cases, safety requirements of the overall PDS (for example, protection against direct contact) can necessitate the use of special components and/or additional measures. NOTE 2 For the purposes of this International Standard, energy hazards can be, for example, explosion of components or stored energy in capacitors.