Batboard

Hi, I have a question about quieting a noisy AC fan. Does anyone know if the Motorola shops have a fix for an AC fan that is radiating a whining noise that I am getting on 10 and 6M FM ? I am using a Syntor-x lowband and have filtered all DC leads but recently found that its being radiated from the FAN and is comming in through the antennas.I put some caps acrossed the leads at the fan but it didnt work at all. if theres help I sure could use some . thank you all very much The fan is a two speed and is run by a controller. Davie n-3-c-h-u at atlanticbb dot net

Hello

I had the same problem in a mountaineer the brushes in the fan motor were bad all i could do was change the motor

Thanks for your reply, The fan runs great just needs to be quieted down. and am sure somone else has had the same problem. I fixed every other noise and this is the loudest. Davie

Please, does anyone know if the Motorola shops have a filter that will remedy my fan whining noise?? thanks all. Davie

Hello

The brushes are just starting to wear out the fan will still run until the brushes fail completely thats what happend to me in the winter the only reason I knew it was going to happen was the noise in my radios includeing my spectra.

Thank you for your reply, unfortunatly its made this noise since it was new. I added caps acreossed the power line right at the fan motor and that did very little, I ordered a new replacement fan and am going to shield it from the fan down to the controller and hopfully ground both ends of the shield to chassis. the fans on VW passats are china or japan made and come in a composit frame but they DO have a power cord with a plug so after I shield it it will be plug and play.(I hope) Davie

I installed a new fan and shielded it still the same loud whining sound (like a fire sirene) so brushes are not the problem.Davie

I've run into similar problems with cooling fans on heavy equipment nailing VHF receivers. They created a cloud of RFI that desensed the rcvrs by about 10db. The best I could do was attenuate it 5db with caps on the fan power lines. It was radiating from the fan housings, and short of experimenting with different manufacturer fans, I could not eliminate it.

Has anyone tried to put some of the snap on ferrite cores on the wires? For the low frequency, it would take a good sized core, but it's worth a try. Maybe even make a couple of turns through the core.

Jim