UPS Noise

[Anonymous user]

Hi, I purchase  brand new  UPS APC 1400VA (BX1400U-MS). 

But My UPS has noise  during power on. Is this normal? (watch the video below)

[Anonymous user]

It's happen only fisrt hour and quiet later

[BillP · Accepted solution]

Hi Phak,

This type of noise from the UPS is sometimes referred to a "Coil Noise" and is somewhat normal. At times this noise may fall within an audible frequency range which is within human hearing. It is caused by varying magnetic fields surrounding the metal coils of inductors and transformers, which is called magnetostriction. There is no way to correct for this in the field, however it does often "go away" after a period of break-in of the components. When I say "go away" I mean the audible frequency will often move to a level which is no longer audible to you. I have see some instances where children and animals are much more susceptible to the noise, as their hearing is often more sensitive than that of an adults.

Secret Squirrel