CEI IEC 60076-10-2001 pdf free

CEI IEC 60076-10-2001 pdf free.Transformateurs de puissance – Partie 10: Determination des niveaux de bruit Power transformers – Part 10: Determination of sound levels.
Sound pressure measurements shall be made using a type I sound level meter complying with IEC 61672-1 and IEC 61672-2 and calibrated in accordance with 5.2 of ISO 3746.
Sound intensity measurements shall be made using a class 1 sound Intensity instrument complying with IEC 61043 and calibrated in accordance with 6.2 of ISO 9614-1. The frequency range of the measuring equipment shall be adapted to the frequency spectrum of the test object. that is, an appropriate microphone spacer system shall be chosen in order to minimize systematic error&
The measuring equipment shall be calibrated immediately before and after the measurement sequence. If the calibration changes by more than 0,3 dB, the measurements shall be declared invalid and the test repeated.
5 ChoIce of test method
Either sound pressure or sound intensity measurements may be used to determine the value of the sound power level. Both methods are valid and either can be used, as agreed between manufacturer and purchaser at the time of placing the order.
The sound pressure method of measurement described in this standard is in accordance with ISO 3746. Measurements made in conformity with this standard tend to result in standard deviations of reproducibility between determinations made in different laboratories which are less than or equal to 3 dB.
The sound intensity method of measurement described in this standard is in accordance with ISO 9614-1. Measurements made in conformity with this standard tend to result in standard deviations of reproducibility between determinations made in different laboratories which are less than or equal to 3 dB.
6 Load conditions
6.1 General
Load condition(s) shall be agreed between the manufacturer and purchaser at the time of placing the order. If a transformer has a very low no-load sound level, the sound due to load current can influence the total sound level in service. The method to be used for summing the no-load and load current sound levels is given in Clause 14.
Current taken by a reactor is dependent on the voltage applied and consequently, a reactor cannot be tested at no-load. Where sufficient power is available in the factory to permit full energization of reactors, the methods to be followed are the same as those for transformers. Alternatively, measurements may be made on-site if conditions are suitable.
Unless otherwise specified, the tests shall be carried out with the tap-changer (if any) on the principal tapping. However, this tap position may not give the maximum sound level in service. In addition, when the transformer is in service, a superposition of the flux at no-load conditions and the stray flux occurs which causes a change in the flux density in certain parts of the core. Therefore, under special conditions of intended application of a transformer (particularly variable flux voltage variation), it may be agreed to measure the sound levels on a tapping other than the principal tapping, or with a voltage other than the rated voltage on an untapped winding. This shall be clearly indicated in the test report.
6.2 No-load current and rated voltage
For measurements made on the test object with or without its auxiliary cooling plant, the test object shall be on no-load and excited at the rated voltage of sinusoidal or practically sinusoidal waveform and rated frequency. The voltage shall be in accordance with 10.5 of IEC 60076-1. If a transformer is fitted with reactor-type on-load tap-changer equipment where the reactor may on certain tap-change positions be permanently energized, the measurements shall be made with the transformer on a tapping which involves this condition and which is as near to the principal tapping as possible. The excitation voltage shall be appropriate to the tapping in use. This shall be clearly indicated in the test report.CEI IEC 60076-10 pdf download.