AC LC filter damaged

[2PAC Mafia]

Hi,

I have an Ektron board from an industrial washing machine. I see it has a triac damaged and also the 220Vac input filter, 2 coils burnt and capacitors too. Capacitors are 2n2 400X1 250Y2 and inductors I don´t know which value they were.

Two questions:

- Which value should I choose for those inductors? 5 mH? The size is like 1/4w standard resistor.

- Why do we have these values 400X 250Y for the voltage as if it is in an axis? Are filter capacitors always like those or you can use standard also?

 

[JimB]

Have a look here:

and here:
**broken link removed**
to learn a bit about X and Y rated capacitors.

JimB

 

[Nigel Goodwin]

- Why do we have these values 400X 250Y for the voltage as if it is in an axis? Are filter capacitors always like those or you can use standard also?

It's absolutely essential that you use the correct rating capacitors, normal ones won't do - and would leave you seriously liable for carrying out an unsafe repair.

 

[2PAC Mafia]

Have a look here:

and here:
**broken link removed**
to learn a bit about X and Y rated capacitors.

JimB

Thanks for the info Jim B, I´ll check it later when I have some time.

It's absolutely essential that you use the correct rating capacitors, normal ones won't do - and would leave you seriously liable for carrying out an unsafe repair.

OK, no problem, I´ll find them, anyway I have 4,7nF with X-Y same voltages. What about the inductors?

 

[dr pepper]

Probably isnt good to guess the values, are the chokes rewindable?, if so that might be the way to go, even then though if the core has been cooked it might have changed its properties.
As mentioned those caps are critical, there are safety reasons for using class x/y.
It would also be good to see if you can find why the filter and triac is toasted, has the motor burnt out and down to earth?

 

[Nigel Goodwin]

It would also be good to see if you can find why the filter and triac is toasted, has the motor burnt out and down to earth?

That wouldn't kill the caps - a FAR more likely reason is excessive mains voltage, VERY common in some countries (such as Spain!).

I've repaired countless satellite receivers brought back from Spain killed by high mains.

 

[2PAC Mafia]

Probably isnt good to guess the values, are the chokes rewindable?, if so that might be the way to go, even then though if the core has been cooked it might have changed its properties.
As mentioned those caps are critical, there are safety reasons for using class x/y.
It would also be good to see if you can find why the filter and triac is toasted, has the motor burnt out and down to earth?

I want to attach some pictures but my server now is giving me an error and when I try to Upload a file with ETO is not showing me files (jpg, pdf, gif...), I don´t know the reason.

 

[2PAC Mafia]

The inductors are same size and view as standard resistors... Can I take the LC filter from another board which uses 220Vac input? Finally the filter should work in same way but components may be are for more power, isn´t it?

 

[dr pepper]

The inductors and chokes make up a filter, other values will not provide effective filtration.
You could redesign the input filter and fit all new parts, or use a pcb designed for the purpose, theres probably some on ebay.

I was thinking the motor was supplied through the chokes, and the motor had pulled too much current frying them, but by the sound of it the filter just supplies the electronics, so nige's idea is probably correct, so it would be good idea to make sure if its an smps that the mains rectifier and storage cap are ok too.

 

[2PAC Mafia]

Hi guys,

I put some pictures and the schematic:

http://www.restoretronic.com/descargas/Ektron/esquema.jpg
http://www.restoretronic.com/descargas/Ektron/Inductancia.jpg
http://www.restoretronic.com/descargas/Ektron/1.jpg

3 pin connector is the Vac input. 5 pin connector is the Vac output, 2 last are going to relays so not important as the problem was coming or from the load or from overvoltage.

As you see the inductor seems a resistor... The parallel capacitors are 2,2nF and the serial one 0,1 uF. I don´t have information about what is behind 5 pin connector, they only gave the board. What to you think about the inductors?

 

[dr pepper]

Thats interesting, kind of.
When I looked at the schem I thought thats a differential choke, then when I saw the photo of the pcb I was alsmost certain it was, but then you show us 2 inductors that look like resistors.
Its almost as though the manufacturers intended to fit a differential choke then didnt they fitted individual inductors.
A diffrential inductor (theres probably other names too) is a coile with 2 windings, usually in opposite driections, so that high frequency noise on one line gets cancelled by the same noise on the other linea due to the opposing windings.
They will probably be low values esp looking at the size of them as they will need to handle at least a few ma.
Will the manufacturers tell you what they are, well these days they probably dont know it'll be outsourced, could you look at another one that still works and get the colour codes?
The circuit woudl probably still work with them linked out, however that wouldnt be good practice as noise from the triac circuit which can be bad would be transmitted through the mains wiring.

 

[2PAC Mafia]

You know dr pepper, I would say know may be somebody fitted there a resistors instead of its original noise filter because as you can see at the picture they seem resistors. Usually when they are inductors the components body colour is green.
I didn't contact to the manufacturer, under my experience it's wasting time, they are italian. I couldn't find any info at Internet to find the original value.
I think I will put a choke from another 220v filter board or just jump them to try it informing my customer about that solution.
The triac is for 8A.

 

[dr pepper]

My sentiments too.

And thats just what i would do, I just didnt want to say it in case you did it and got into trouble on my advise.