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Phil Allison[_3_] Phil Allison[_3_] is offline
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Default Fan causing MW RFI


Jeff Layman wrote:

I have a 6-months old Fantasia ceiling fan (mains powered, with 6-speed
reversible dc motor) which is causing a lot of interference on MW. FM
is not affected. The interference is there on forward or reverse
rotation, worsens as the speed is increased,, and appears on portable as
well as mains-powered radios.

I can return it to the supplier for replacement or refund, but it is a
bit of a rigmarole to remove and refit. All the electronics are sealed
in, and the only accessible wiring is to the mains connector. Is there
any point in trying some sort of screening or RFI suppression on the
mains wiring before I take it down?



** The instructions say all units must be earthed - is yours?

You could try a suppression cap across the line( active to neutral) at the terminal block - close as possible to the fan itself. A class X1 or X2 film cap of about 470nF is a good place to start. But I bet there is one inside the fan already.

I expect the fan motor is a BLDC type, possibly operating at mains voltage, and the pitch of the noise on AM would vary with its speed.


BTW:

Are you living far from AM transmission sites - say than 50 kms ??

BTW 2:

Are you living in a metal clad ( aluminium sided ) building ?

Either of the above means the AM signals inside your home will be very weak.


..... Phil