Generating using a DC brushed motor

[lucy_b14]

Good Evening

I'm interested in the possibility of using a DC brushed motor as a generator (ie running it in reverse - mechanically turning the shaft to produce electricity).

However, I have no idea how to calculate the power I could potentially achieve. Any tips or equations in particular would be greatly appreciated.

Thanks

 

[berkeman]

Good Evening

I'm interested in the possibility of using a DC brushed motor as a generator (ie running it in reverse - mechanically turning the shaft to produce electricity).

However, I have no idea how to calculate the power I could potentially achieve. Any tips or equations in particular would be greatly appreciated.

Thanks

A good start would be to look at the specifications for the motor's normal operation. What is the input current listed for the specified DC input voltage? That will give you a pretty good ballpark idea of what the output current will be when you are turning the motor fast enough to generate the specified voltage. Motors are pretty efficient, so you may only have to derate the motor numbers by a couple tens of percent to get the generator numbers.

Be sure to calculate the associated powers, so you know what kind of input mechanical power will be required to get that output electrical power.

 

[berkeman]

Oh, and the output of DC motors is generally pretty noisy, due to flyback impulses when the brushes are switching. Be sure to plan on an output snubber/filter circuit to clean up the DC output voltage.

 

[cshieldsx]

Please excuse me if this comment is stupid, but would it not be possible to use a brushless DC motor - and then there wouldn't be an issue of a noisy output signal ?

 

[cshieldsx]

Ah, You need a more complex control system to run a brushless dc motor correct ?