DC waterpumps and powerheads.

[sub.42]

Hiya Guys,

Just wondering if any of you have ever come across any DC pumps for aquatic use?

My main reason for asking is that most DC pumps (ie, direct current, or low voltage), are much quieter than the noisy AC units we are mostly exposed to with our hobby.

Most of the problems aquarium pump designers have are that the pump must be anti-clog, continuous duty, and most importantly of all, be cheap!

DC pumps are not cheap, and I don't expect them to be cheap to run, as DC pumps draw more current than AC pumps, but what the hell!

I am investigating suppliers at the moment, and I am hoping to find a pump for us folks whom cannot stand the noise!

Any info would be much appreciated.

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[Silly me]

DC motor is mostly brusshed motors, make more noise use more power and will not beable to continuous run.. Brussless DC motors need a very fansy controler to run. and sometimes have a false start were the motor just hums and dont move.

AC brussless motors doesnt need that fansy controler to run, has much more power for the same amp's. If you have a brusshed AC motor, no wonder you have to much noise.

All my AC pumps I have make almost no noise, I also dont have a single airpump in any of my tanks as I hate the noise the bubbles makes. a powerhead should make a noise at all.

My main reason for asking is that most DC pumps (ie, direct current, or low voltage), are much quieter than the noisy AC units we are mostly exposed to with our hobby.

what DC motor/unit do you want to compare to what AC unit/motor.

 

[sub.42]

Silly me,

ALL my pumps and filters make noise. The point I am trying to make is that some of us are a little more susceptible to the noise made by our equipment.

I work with water pumps in large scale water recycling plants everyday, and I have always found a DC motor to be quieter than an AC motor, purely because of the physics involved. Within an AC motor, you have noise generated by the alternating sine wave that is the alternating current. Unless the unit is very well balanced, it won't take a lot to induce noise, the unit merely sets up sympathetic resonances because of the AC field being used, and the nature of the AC motor unit.

Grab your average Juwel powerhead, and try to rotate the impellor. It wont give at three or for points throughout its 360 degree rotation. Now, when you apply power to this unit, it will have the same issues of overcoming the initial resistance at these points. This will be transfered into the aquarium as noise via vibration. Simple physics.

That is the type of noise that annoys me, and also the type of noise you do not get from a DC motor. Ok, a little of the noise is decided by the design of pump, be it rotary vane, screw, scroll, or whatever, but a lot of it comes down to balancing the whole thing.

Cheap AC pump means noise, expensive ac pump means less noise, but still noisy.

DC pump means no noise generated by motor unit ( and they can be made to start with 'no stall' technology, its not 'fancy', and not too costly), and me free to choose what type of pump unit. Thats why your PC's CD-rom drive is most likley to be DC, powered by a power stepping transistor.

I'm not bothered by cost too much, just want a very quiet life. B)


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