How to arrest the noise signal in the bridge output during contactor on/off

[prakashvenugopal]

Hi all,

I am facing the issue of noise signal comes into my bridge rectifier circuit through transformer 220v.

I am using 220v ac primary --> 22-0-22v secondary. This secondary output is given to bridge rectifier circuit with 2200 uf electrolytic capacitor in the bridge output --> regulator

I am switching ON/OFF the contactor in the same line of transformer 220V ac. Huge noise seen in the bridge rectifier output during contactor ON/OFF. This is reflecting in the regulator output also.

How to solve this noise? Kindly help.

I am attaching the noise signal seen during contactor on/ off in the transformer seconary waveform 0-22v ac measured in oscilloscope and also bridge output signal. Kindly check and please help.

Regards,
V. Prakash

 

[prakashvenugopal]

Hi,

Can you guys please recommend the transformer party purchase details or online purchase.? Even 230V ac to 230V ac is enough for study. 1:1 transformer with earth screen. Here the transformer parties are not aware of this.

Regards,
V. Prakash

 

[prakashvenugopal]

Hi,

What does the PE for this transformer does?
Already having PE earth in transformer primary

Regards,
V. Prakash

 

[Easy peasy]

PE = protective earth, i.e the normal earth used in any switch board or distribution board.

 

[prakashvenugopal]

Hi,

The earth you are talking about in transformer is different from this PE earth?

Regards,
V. Prakash

 

[Easy peasy]

please observe the words carefully " earth screen " usually a brass band between pri & sec, overlapping but not a shorted turn.

--- Updated Aug 28, 2021 ---

often quite thin.

 

[D.A.(Tony)Stewart]

Transformers will leak inductive spikes thru wiring coupling capacitance but depends on ESR of load and errors from long scope ground. There is also common mode noise issue which can be reduced with a CM choke and RF film caps to PE.