Which component is this in an smps just after bridge rectifier.

 

Welcome to AAC.

Those are diodes, but the only candidate a quick search of markings offers the LUMA140 400V 1A ultrafast rectifier. But given the position, the 1A capacity seems low and the logo is wrong.

In any case, they are diodes.

 

Welcome to AAC.

Those are diodes, but the only candidate a quick search of markings offers the LUMA140 400V 1A ultrafast rectifier. But given the position, the 1A capacity seems low and the logo is wrong.

In any case, they are diodes.

Thanks for guidance.

 

But given the position, the 1A capacity seems low

Could you explain this?

 

Could you explain this?

It is surmise based on:

Which component is this in an smps just after bridge rectifier.

If the diodes are just after the bridge, it would have to be a <1A supply, and, the size of the diodes suggests >1A rating. It was said concerning the only part I could find that seemed to have similar markings—and those were not a real match (UM41 instead of UM40, and the logos aren’t the same company).

The comment was actually a bit redundant since I was eliminating something I didn’t think was the right part any way.

 

Thanks.

 

It is surmise based on:



If the diodes are just after the bridge, it would have to be a <1A supply, and, the size of the diodes suggests >1A rating. It was said concerning the only part I could find that seemed to have similar markings—and those were not a real match (UM41 instead of UM40, and the logos aren’t the same company).

The comment was actually a bit redundant since I was eliminating something I didn’t think was the right part any way.

You are right. It may not not be just after bridge, but this is installed nearest to bridge. This is a double layer PCB. In 24 V 10 Amp smps allen Bradley SMPS unit. I have to check again the circuit, i am not too good in electronics good so...

 

It is surmise based on:



If the diodes are just after the bridge, it would have to be a <1A supply, and, the size of the diodes suggests >1A rating. It was said concerning the only part I could find that seemed to have similar markings—and those were not a real match (UM41 instead of UM40, and the logos aren’t the same company).

The comment was actually a bit redundant since I was eliminating something I didn’t think was the right part any way.

Here is image of circuit

 

Here is image of circuit View attachment 309842View attachment 309842

If you can explain more please do. Thanks

 

Those look like they have been replaced (based on the sloppy soldering.). Were probably originally same as the other two next to them.

 

I dont have much to add but the logo is "General Semiconductor" (now owned by Vishay). UM is the code you need to find the specs in the datasheet. You can ignore the 41 its just production code. I didnt have time to look but its should be easy to search google for it.

 

I dont have much to add but the logo is "General Semiconductor" (now owned by Vishay). UM is the code you need to find the specs in the datasheet. You can ignore the 41 its just production code. I didnt have time to look but its should be easy to search google for it.

View attachment 309843

Thanks, i have checked datasheet from vishay, UM is for 1000 Volt

 

I dont have much to add but the logo is "General Semiconductor" (now owned by Vishay). UM is the code you need to find the specs in the datasheet. You can ignore the 41 its just production code. I didnt have time to look but its should be easy to search google for it.

View attachment 309843

In the case of the diode I was discussing, the code for marking was UM followed by 2 digits which denoted capacity. There was no date code. Date codes are certainly a source of confusion for many trying to track down a part and it’s good to know they exist (and usually the second line).

But in the case of parts marking there are many exceptions and no standards for accountability so if the default assumptions fail—though they should be good 80% or more of the time—variations need to be tried.

Thanks for recognizing the logo, I didn’t.

 

Possibly Vishay GDZ27B-G 27V zener.

https://www.vishay.com/docs/83334/gdzg.pdf

 

This is ultrafast diodes as @ya'akov said

 

This is ultrafast diodes as @ya'akov said

That looks correct based on the package and application.