Re: smart fans

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

Polyna-Maude Racicot-Summerside wrote:
> > Like I already wrote, modifying voltage doesn't change speed of a motor
> > (fan).

tomas@tuxteam.de wrote:
> I disagree. [...]
> I have no idea what the motherboard/fan manufacturers actually do, though.

Voltage reduction is a tradional method to curb overly eager DC fans. I have
seen successful use of resistor adapters between fan cable and mainboard.

A quick search with "fan voltage control" yields
  https://en.wikipedia.org/wiki/Computer_fan_control#Linear_voltage_regulation
and others which state that 2-pin and 3-pin are only controllable via
voltage reduction whereas 4-pin indicate the capability for the competing
method of Pulse-Width Modulation (PWM).

Resistors can be seen at
  https://www.amazon.com/computer-fan-resistor/s?k=computer+fan+resistor


rhkramer@gmail.com wrote meanwhile:
> A voltage controlled DC (computer fan) motor can be controlled /
> regulated down to about 40% of full rated speed (depending on the motor).

That's what i read in the web and what i witnessed as effect of resistors on
dumb fans.


Have a nice day :)

Thomas