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