Hi,

I am working on a project and I need to generate a very tiny and minuscule hydraulic electricity generator.

I have not finalised it yet but I am looking to make something with following dimension: length=15mm to 20mm. Width=5 to7 mm and height=3mm to 6mm

Is there any of the shelf micro electricity-generator out there? If not, is it possible to home built one? How should I go about this?

thanks

 

A DC motor can be used as a generator but one that small won't put out hardly any power especially with a typically slow hydraulic motor.
http://www.mpja.com/Micro-Vibrator-Motor-15-3VDC/productinfo/32514+MD
Super small coreless, DC vibrator motor used in toys & cell phones. 3/4” leads.
Rated: 1.4-3VDC. Draws 90mA @ 1.5V; 190mA @ 3V.
L:20mmW: 8.9mm H: 4.4mmWT: .001

 

Cellphone vibrators are tiny DC motors that can be found very cheaply, even free if you tear apart an old phone. But I wouldn't know how to mechanically adapt one to being a generator. You'd need to spin it fast to get much juice out of it.

 

How much power do you need to generate? When you say "hydraulic" I presume you mean water. What pressure and flow rate do you have available? First thing to consider is the basic physics: you cannot get more energy out than you put in and if the device is miniature, the efficiency will be very low. Expect well below 10%.

Permanent magnet DC motors will work as generators. But cheap motors have poor magnetic coupling and have to spin very fast to generate useful power. One way to test if a motor will be any good is to short the motor terminals and to turn by hand. Compare to when the terminals are open. Any difference?

Brushless motors are better. Try this with a disk motor salvaged from an old hard disk drive. Short all 3 terminals together.