BS 5611:1978

National foreword
Cooperating organizations
1. Scope
2. Selection of a tap-changer
2.1 General remarks
2.2 Insulation level
2.3 Current
2.4 Breaking capacity
2.5 Number of tapping positions
2.6 Discharge problems with change-over selectors
2.7 Mechanical life
2.8 Motor-drive mechanism
2.9 Pressure and vacuum tests
2.10 Low-temperature conditions
2.11 Continuous operation
3. Location of oil-immersed tap-changer components
3.1 Tap selectors
3.2 Diverter and selector switches
3.3 Oil level alarm contacts
4. Field service
4.1 Safety of operation
4.2 Parallel operation
4.3 Contact erosion and oil contamination
5. Information required with enquiry or order
5.1 Rating and general data
5.2 Insulation level
5.3 Pressure, vacuum and temperature requirements
5.4 Special
5.5 Fittings
5.6 Motor-drive mechanism

Selection of a tap-changer, location of oil-immersed tap-changer components, field service, information required with enquiry or order.

This application guide is intended to assist in the selection of suitable on-load tap-changers for use in conjunction with the tapped windings of transformers or reactors which, in the following text, are referred to as transformers.

As in the second edition of IEC Publication 214, On-load Tap-changers [revision of Publication 214 (1966)], the designation “on-load tap-changer?? is shortened to “tap-changer?? in the remainder of this guide and all the tap-changers referred to shall be presumed to comply with the requirements specified in IEC Publication 214.

The recommendations of the application guide are not mandatory and only represent advice to the tap-changer manufacturer and purchaser. The responsibility for the correct application of the fully assembled tap-changer in connection with the transformer is with the manufacturer of the transformer.