I am a mechanical engineer and am working on a project. This project consists of a rotating shaft and I would like to generate power from that rotating shaft.The shaft will not be rotating continuously.

What are some basic things I need to know in order to generate power from the shaft? Do I use an alternator? I have read in many places that a generator converts mechanical energy to electrical but whenever I look up generators I end up with residential generators which is what I am not looking for.

Some other questions are do I need to regulate the RPM to create a certain frequency and should I make sure the shaft rotates continuously.

Sorry for being so clueless but I have been searching the internet for a while and this seems like the best place to get my questions answered. Thanks and any help would be appreciated.

  • \$\begingroup\$ How much power is available at the shaft? What kind of power output do you hope to achieve? \$\endgroup\$ Commented Nov 3, 2013 at 3:29
  • \$\begingroup\$ A force of about 1500 lbs will be used to turn the shaft. There may be losses in force. The feasibility is not of importance right now. Power output is open ended currently. \$\endgroup\$
    – user31204
    Commented Nov 3, 2013 at 4:01
  • 1
    \$\begingroup\$ This question, while seeming broad and open ended, can provide some solid help to OP and others. It should remain open. \$\endgroup\$
    – Passerby
    Commented Nov 3, 2013 at 4:12
  • \$\begingroup\$ Is the shaft end available for you to mount something on it, or modify? Can you add anything to it? Is the shaft fairly stable and fixed into position? An alternator (ac) or generator (dc) would work, just like how a car uses one attached to a pulley or belt to charge the car battery. It's simply an issue of mounting or connecting the alternator. The battery charging circuit would be fairly simple. \$\endgroup\$
    – Passerby
    Commented Nov 3, 2013 at 4:15
  • \$\begingroup\$ Yes the shaft is a free end. I was thinking of sending the power to the grid. If that is possible what configuration should I go with? \$\endgroup\$
    – user31204
    Commented Nov 3, 2013 at 4:25

1 Answer 1


Mechanical Generation of Power is basically how we first got electricity. It's a fairly common application, and there are over a billion of them running around outside. Automobiles have been using rotating shafts to power themselves since the very start.

The schematic for it is fairly simple. An Alternator going into a rectification stage which is then tapped into a battery for power storage, or directly to the rest of the circuit if the shaft can generate a fairly steady speed and voltage.

enter link description here

Automotive alternators have been design in a way to couple the alternator to the shaft without directly mounting it around it, through the use of a belt or pully. As long as the shaft is fixed in place, and the alternator can be mounted along side, this works great (Safety first of course). There is a minimum RPM for stable generation, and output voltage will vary based on the RPM, so you have to work around that (Use a regulator circuit). The alternator's ideal rpm should match the Shaft's range of speeds.

A not typical setup for illustrative purposes: enter image description here


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.