Timeline for Is there an ideal PWM frequency for DC brush motors?
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 24, 2016 at 7:07 | comment | added | Drunken Code Monkey | Just use a Schottky barrier with around 0.1V drop if the 0.7v of the silicon diode bothers you (it really shouldn't). | |
| Jun 23, 2016 at 23:10 | comment | added | Craig McQueen | @supercat: What is your recommended alternative to short the motor when in the "off" state? A second FET? Could you show or refer to an example circuit diagram? | |
| Jun 23, 2016 at 13:47 | comment | added | supercat | @CraigMcQueen: A flyback diode will effectively short out the motor while forward current is continuing, less a 0.7-volt drop. At 24VDC the 0.7V drop may not be a problem, but performance would be better without it. | |
| Jun 23, 2016 at 4:52 | comment | added | Craig McQueen | Alternatively, use a flyback diode. For an inductive load (e.g. motor) it's important to have a path for the current when the supply is switched off, to avoid a voltage spike which could kill your switching transistor. | |
| Jun 22, 2016 at 19:44 | comment | added | supercat | @NateSan: Because the motor has inductance, current will continue to flow even when you try to switch it off. Shorting the motor will allow the energy to continue doing useful work during the off period, and will reduce the amount of energy you need to dissipate outside the motor | |
| Jun 22, 2016 at 17:45 | comment | added | Nate San | I actually wont be grounding it during the off period, friction will stop the motor very quickly. So I didn't see a reason not to leave it floating between duty periods. | |
| Jun 22, 2016 at 16:32 | history | answered | supercat | CC BY-SA 3.0 |