Tumble drier interference suppressor.

[Fredxx]

Do explain how? I know you can't when it comes to anything engineering or technical.

[Fredxx]

When was the last time you saw a brushed motor in a tumble drier? It just goes to show that you don't have a clue.

[nib]

If it has an induction motor, heating by resistors with no current control and a mechanical timer with a synchronous motor, it probably won't create any interference while running; but it might still create switching spikes when switching on or off which the manufacturer would have to control.

But then there wouldn't in practice be any issue with omitting the filter?

nib

[RJH]

Yep, same here.

As mentioned up thread, the ones Beko now supply seem to have been updated - that what I fitted anyway, and the price was about the same.

[Jack Harry Teesdale]

Why bother replacing it, the T/D will work just as well without and it won't trip.

[nothanks]

Manufacturers have to demonstrate that equipment meets the conducted and radiated emission specifications (amongst other things) in order to be able to CE mark their products and "place them on the market". You removing the filter from one device is not going to affect anything.

[Paul]

But you'd agree though, that the implementation in this case, is just stupid.

That filter is not fitted because of some motor issue.

That filter is fitted, because the machine has an SMPS providing regulated DC power to some stinking processor. And undoubtedly, the machine has unfiltered digital wiring running all over the place, an emissions-guy worst nightmare. That means the box is filled to the scuppers, with emissions.

The filter need only have gone in the SMPS path, and the filter then needs only a tiny current rating. The filter does not need to be filtering any electric fire current or any motor currents. They could put passthru filter caps, on the wiring exiting the controller board.

There might still be some coupled interference currents, between the SMPS area, and AC wiring for the non-digital parts. Perhaps an emissions expert could tell us what to use for that. I don't know what a large ferrite bead will do, when heavy AC currents are present. I hope it would not react, but I'm not sure about that.

There are plenty of power tools and other things we use daily, which have no broadband filter networks on input. Those filters seem to be reserved for SMPS-equipped products.

Paul

[nothanks]

No, I would not agree. If a filter is going to stand a chance of being effective it needs to be on the machine input, otherwise the wiring between the input and the filter receives radiated interference from anything that is radiating (SMPS, motor controller, whatever) inside the machine case and transmits it outside the case. This is why filters should always be at the point of entry. I've now hinted at one of my former lives ;-)

[John Walliker]

That doesn't explain why my tumble drier had a filter (now removed after the sticky liquid came out). It has a mechanical timer driven by a small synchronous motor and the main motor is also synchronous. There is no cpu, no display or anything likely to generate RF. The only thing that might need suppression is switching spikes. John