11
$\begingroup$

How can you calculate how much power can be generated by a motor when used as a generator (like a motor used in a wind turbine)?

Does the power depend on how fast the magnet is rotated? If so, is there a equation that lets you know given the rpm, how much power should be generated?

Also, how can I account for limiting factors such as the strength of the magnet (moving a coil around a stronger magnet should give more power than moving coil around a weaker magnet)?

$\endgroup$
2
  • 3
    $\begingroup$ For each type of motor/generator, there are well-known equations for the torque $T$. The power $P$ is the torque $T$ multiplied by the rotational speed $\Omega$: $P=T\Omega$. $\endgroup$ – Karlo Mar 25 '16 at 7:55
  • 3
    $\begingroup$ @MWc You should expand on that a little and make it an answer. $\endgroup$ – Chris Mueller Mar 25 '16 at 14:02
2
$\begingroup$

When used as a generator, a motor can generate approximately the same power that it requires for operation as a motor at rated speed and torque.

In general, the voltage produced by a generator is directly proportional to speed. Power is proportional to voltage multiplied by current. The maximum current that can be drawn from a generator is generally a fixed value that is not determined by speed. Therefore the power that can be produced by a generator is directly proportional to speed.

The effect of changing the strength of the magnetic field (field excitation) is generally to increase or decrease the voltage generated.

There are a number of factors that determine a generator's limits for safe operation. Those factors are generally similar between motor and generator operation. They need to be considered for each different type of machine, AC and DC, wound-field and permanent-magnet, induction and synchronous, plus all of the sub-categories and design variations.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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