SparkFun Forums

[RossWaddell]

Not sure if this is the right place to ask this question, but I'm hoping somebody here has some experience with DC motors and can help me out.

I'm looking for an extremely quiet DC motor to run at 9V but low RPM. I've tried some Pololu motors and a Sayama one that's quite common, but both are too loud for my project (the motor is going to sit inside a plastic model kit and spin a hemispherical dome).

Any suggestions? You can see my WIP of the circuit here: http://youtu.be/9dDRYyaE854

[RossWaddell]

Forgot to mention - the motor needs to be roughly the same size as the Sayama:

http://www.goldmine-elec-products.com/p ... ber=G16300

[jremington]

I've salvaged miniature stepper motors out of discarded floppy disk and CD drives. They are low power and very quiet, but you do need a simple driver.

[waltr]

Noise is typically from the gears in the reduction. The design and more important the gear precision is what makes a quiet gear train. Therefore a very high quality gear motor will be quiet.
Read the artifices here to learn more:
http://www.micromo.com/gearhead-tutorials.aspx

I have found high quality, quiet gear motors from surplus outlets for a fraction of their original price.
Problem with surplus is you never know what they will have in stock.
If you have the budget then buy a FAULHABER, else buy surplus looking for FAULHABER gear motors.
I have gotten a few for about $30 each (original price is over $100 each).

Next step for a quiet gear motor is how it is mounted and what it is mounted on. I have a number of Pololu gear motors. For the price these are nice and fairly quiet. I mounted one to a sheet of thin plywood and the noise was huge due to the plywood acoustically amplifying the noise. By changing to a 'floating' mount (rubber pad between the motor bracket and the plywood) the noise was greatly reduced.

[RossWaddell]

I've salvaged miniature stepper motors out of discarded floppy disk and CD drives. They are low power and very quiet, but you do need a simple driver.

I don't need the function of a stepper motor (my PIC just slowly increases the PWM tot he motor to spin it up to the desired RPM. Nothing fancy) so I'm a bit concerned about how they would function as just a typical DC motor. But I have to admit I don't know much about steppers.

[RossWaddell]

Noise is typically from the gears in the reduction. The design and more important the gear precision is what makes a quiet gear train. Therefore a very high quality gear motor will be quiet.
Read the artifices here to learn more:
http://www.micromo.com/gearhead-tutorials.aspx

I have found high quality, quiet gear motors from surplus outlets for a fraction of their original price.
Problem with surplus is you never know what they will have in stock.
If you have the budget then buy a FAULHABER, else buy surplus looking for FAULHABER gear motors.
I have gotten a few for about $30 each (original price is over $100 each).

Next step for a quiet gear motor is how it is mounted and what it is mounted on. I have a number of Pololu gear motors. For the price these are nice and fairly quiet. I mounted one to a sheet of thin plywood and the noise was huge due to the plywood acoustically amplifying the noise. By changing to a 'floating' mount (rubber pad between the motor bracket and the plywood) the noise was greatly reduced.

Thanks waltr. I have planned to mount them to rubber or a foam sheet to reduce the noise, and then surround them (although not tightly) with foam rubber pipe insulation).

I'm going to look for the motors you mentioned. The only ones I've found so far that are advertised as 'quiet' and have a low RPM is this one: http://www.robotmesh.com/12v-high-quali ... QgodQ3EAWg

BTW, did you buy yours from an online surplus store or a brick-and-mortar one?

[RossWaddell]

Found this on eBay (http://www.ebay.com/itm/like/271116997987?lpid=82) - is that similar to what you were thinking, waltr?

[waltr]

Yes, that is similar but the ones I had gotten that are really quiet are look more like the Sayma gear motor.
If you go surplus you may need to just buy and try until you find the one that meets your requirements.
There are other good gear motor makers. Other really quiet ones I have were made in Switzerland and I'm sure some of the Japanese motors are very good.
Most of my surplus buying is online. There used to be places in Philadelphia (in scary neighborhoods) but most of these are now closed.

[RossWaddell]

Thanks again waltr. Can you please suggest some online surplus places? I know of Electronic Goldmine, but that's it.

What about this one? http://www.dfrobot.com/index.php?route= ... n12vZH-Jg0

[lyndon]

My favorite online surplus outlets are BG Micro, All Electronics and MPJA. Locally in the MSP area is Ax Man. Love that place, but haven't been there in years.

[waltr]

Here are a few I know of:
http://www.sciplus.com/s/c_15/5
They have a "MAXON Swiss made gear motor"
An old place:
http://www.surpluscenter.com/electric-m ... earmotors/
http://www.surplussales.com/motors/Motors-1.html

Found another Maxon motor:
http://www.skycraftsurplus.com/3vdcmoto ... ction.aspx

http://www.electronicsurplus.com/leftnav/motors/dc.cat
Has some ESCAP Motors but didn't see any with gears

I've bought from this place a few times. Has Maxon &Faulhaber gear motors:
http://www.allelectronics.com/make-a-st ... ors/1.html

http://www.bmius.com/c-235-small-electric-motors.aspx

This place is mainly Optics but can have small motors. They are about an hour from me so I have been there a few times and its great fun looking at everything.
http://www.surplusshed.com/

Also, Google "surplus DC gear motor" to find lots more. It does take some time to look to see what is available. Then more time to try and find specs. Some time spec can be found (for off the shelve parts) but many times surplus items were originally custom so no specs.

I have not bought from most of the places I listed above. With surplus I tend to buy what I need from where ever I can find it so not a repeat customer.