Problem with strange vibrating MOV across transformers side

[CMOS]

mov file vibrating

Hi,
I have connected 270V MOV across the primary side of my transformer to protect my microcontroller based circuit from hanging out due to voltage surges. The mains voltage is 220V. The problem I am facing is that as soon as I connect the mains supply, MOV starts vibrating and makes a chattering noise. What could be the reason?

 

[BGA]

Re: Strange Vibrating MOV

What is a MOV?

 

[flatulent]

Re: Strange Vibrating MOV

What is a MOV?

It is a crystalline material which has a bidirectional IV characteristic like a Zener diode. It is used to reduce the effects of transients on the line it is across.

The noise that is generated in the post two above is due to some piezoelectric effect. You should examine the data sheet for the MOV and see if your voltage rating is proper for AC where the peak is higher than RMS.

 

[jorgito]

Strange Vibrating MOV

Hello CMOS,

As far I recall MOV's are specified in terms of DC voltage. If so, you are clippling the AC source!. 220 VRMS have some 310 V peak.

 

[CMOS]

Re: Strange Vibrating MOV

Hello CMOS,

As far I recall MOV's are specified in terms of DC voltage. If so, you are clippling the AC source!. 220 VRMS have some 310 V peak.

Oh..ooo I guess I made a mistake there. I thought MOVs are rated in terms of AC RMS. I have never gone through datasheet of any MOV yet. I'll try searching a few and verify it.