[Amps] 4 wire EBM Papst fan but without using PWM

[Conrad PA5Y]

Hello Manfred thanks for the useful advice. The interference was 
magnetic from the DC wires. Some ferrite and following your advice cured 
the problem and now it is good. I am a weak signal VHF operator and try 
to avoid potential noise sources. It took a while to find a quiet SMPSU!

Regards

Conrad PA5Y

On 2017-01-08 15:48, Manfred Mornhinweg wrote:
> Conrad,
> 
>> I just want to know what to do with the PWM and tacho wires if I do 
>> NOT want to use them.
> 
> The tacho wire is an open collector output. You can simply leave it
> disconnected, and it shouldn't cause any problem. Cut it off close to
> the fan, to minimize noise pickup, just in case. You can also ground
> it there (to the negative fan supply wire), but that's unlikely to be
> necessary.
> 
> The PWM wire is an input, intended to be driven from an open
> collector. Cut it as short as possible, and connect a bypass cap from
> it to the negative fan supply line, as close to the fan as possible. A
> capacitor value like 100nF is fine.
> 
> If after this the fan still gets interfered by the amplifier, you will
> need to install some shielding, using wire mesh where necessary, and
> bypass the fan supply lines to that shielding. Adding ferrite beads
> individually over the supply wires, close to the fan, can also help.
> 
> Manfred
> 
> ========================
> Visit my hobby homepage!
> http://ludens.cl
> ========================
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps