UNE EN 60551 : 93 A1 99

Committees responsible
National foreword
Methods
1 Scope
2 Definitions
3 Instruments
4 Conditions for measurement
5 Measurement of sound pressure levels
6 Calculation of surface sound pressure level and sound power
    level
7 Presentation of results
Appendix
A Test environment qualification procedure
B (normative) Derivation of sound power level from sound
    intensity measurements
C (normative) Determination of sound power level due to load
    currents
ZA (normative) Other international publications quoted in
    this standard with the references of the relevant
    European publications
Tables
1 Correction for influence of background noise
A1 Approximate values of the mean acoustic absorption
    coefficient
Figure
1 Typical microphone positions for noise measurement on
    transformers excluding cooling equipment
2 Typical microphone positions for noise measurement on
    transformers having forced air cooling auxiliaries
    either mounted directly on the tank or on a separate
    structure spaced less than 3 m away from the principal
    radiating surface of the transformer tank
3 Typical microphone positions for noise measurement on
    transformers with separate forced air coolers spaced less
    than 3 m away from the principal radiating surface of
    the transformer tank
4 Cooler with forced air cooling auxiliaries showing
    boundaries of principal radiating surface
5 Typical microphone positions for noise measurement on
    forced air cooling auxiliaries mounted on a separate
    structure spaced not less than 3 m away from the
    principal radiating surface of the transformer tank
6 Typical microphone positions for noise measurement on
    dry-type transformers without enclosures
7 Prescribed contour and typical microphone positions for
    noise measurements according to subclause 5.2.2 on a
    mobile transformer with Schnabel-car tank having
    horizontal bushings and integrated forced air cooling
    equipments with large sound absorbers in front of the
    eight fans
8 Prescribed contour and typical microphone positions for
    noise measurements according to subclause 5.2.2 on a
    mobile transformer with Schnaebel-car tank having
    horizontal bushings and integrated forced air cooling
    equipments with large sound absorbers in front of the
    eight fans
A1 Environmental correction K, in decibels

Specifies the procedures where the sound levels of transformers, reactors and associated cooling equipment are determined to comply with any specifications, together with the characteristics of noise emitted in service.