mains hum

Noun

uncountable

A sound associated with alternating current which has a frequency a multiple of that of the mains electricity.

Japanese Meaning

交流電源（主電源）の周波数の倍数の周波数を持つ、電気機器などから発せられる低周波のハム音

Late at night the steady mains hum of the transformer made concentration impossible.

夜遅く、変圧器からの絶え間ない商用電源のうなりが集中を妨げた。

Sense（1）

A sound associated with alternating current which has a frequency a multiple of that of the mains electricity.