Running pumps on PWM voltage?

[andersson.j]

I was under the impression that pumps shouldn't be run on PWM voltage so I'm currently running my DDCs on analogue voltage.

But a few minutes ago over at procooling in this thread (http://forums.procooling.com/vbb/showthread.php?p=156082#) TerraMex wrote:

pwm is great to control motors.
pumps included. simple and an efficient way, and keeps them running even with a low setting.
It kinda makes sense, why shouldn't you be able to run them on PWM voltage? It's just a motor very similar to the ones in fans? The only thing speaking against it is this pdf (http://www.mcubed-tech.com/download/miniNG_laing.pdf) from mCubed stating that you should:
Set the jumpers for channel B (for the Laing)
like shown in the middle (without speed signal,
analogue voltage, manuel speed mode).

I can't seem to reach anyone over at Laing, my mails can't be delivered, so instead I ask you.

[creidiki]

PWM has the bad tendency of making some motors vibrate, which is bad in a pump, cause a fan you just replace when the bearing dies, but a pump is a little more expensive :)

[Cooper]

erm...what`s pwm ?

[creidiki]

Pulse Width Modulation. A method or digitally regulating voltages by pulsing the full current instead of analgically regulating it. Used by most fan controllers, cause you dont need a heatsink for the poties...

[WeStSiDePLaYa]

erm...what`s pwm ?


pulse width modulation iirc.

[Cooper]

So shorter pulse means lower voltage. Hmm. But there should be some fluctuations. I wonder how big those can be ? PSU also has voltage fluctuations. But imo good PSU has about <1%

[andersson.j]

The DDC pumps has a lifetime of almost six years, I wonder how long it would run on PWM voltage? Two years would be acceptable to me.

[creidiki]

Why does it matter anyway? Your t-ban mng can do analogue, so use analogue, its better.

[KaptCrunch]

better to use a veriable resistor for control motors or carbon pile.
the D5 uses a speed control (http://us.st11.yimg.com/store1.yimg.com/I/pcpowerzone_1885_21098389)

[WeStSiDePLaYa]

i dont see why people would want to slow down their pumps anyways? its not like they make that much noise.

[creidiki]

Not sure, tbh. I cant hear my 50Z at all, let alone over the hard drives and fans...

[andersson.j]

My anti vibration mounted DDCs are very quiet, especially in my sound dampened P180. But it would be fun to vary the pumps speed trough software anyway! :)

[creidiki]

But the mNG can do that with analogue as well, i thought...