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What procedure does SquareD/Schneider Electric use to test the sound level of a Low Voltage Dry Type Distribution Transformer?

Published date: 04 June 2020

What standards of testing are used for Sound levels in SQ D Transformers?

Product Line:
LV Transformers

Applies to Low Voltage Transformers by SquareD/Schneider Electric

Transformer noise level during operation


SquareD/Schneider Electric tests Low Voltage Dry Type Transformers per NEMA ST-20 Section 4.2.10 (1992).

Following are some paraphrased excerpts from that standard:

- Ambient Noise must be 5 decibels below testing value (Prefered 10 decibels) Correction factor used for 5 to 10 dB below
- No acoustically refecting surface, other than the floor, with in 10 feet
- Equipment must be in accordance with ANSI S1.4, 1983
- Average sound is the arithmetic mean of the sound readings (Minus correction factor)
- Five major sound producing surfaces
- ~ 1 foot from each surface @ 1/2 height (less than 8 feet tall)

For a complete print of the NEMA ST20 Standard, you must purchase the standard from NEMA as it is copyrighted material.

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