How would I be able to determine the relationship between the PWM and RPM? It looks to be exponential if I graph it. Would that be the best way to determine the RPM at say 1300 PWM?

Cheers

How would I be able to determine the relationship between the PWM and RPM? It looks to be exponential if I graph it. Would that be the best way to determine the RPM at say 1300 PWM?

Cheers

Hi,

Yes, but you can use some fitting to find the 3rd order equation for the best approximation:

Note: X is the PWM and the result is RPM

You can find the code used to create this equation here.

That’s perfect! Thank you!

Hi @adam,

I see that this equation is for operating the thruster at 16V, is there also an equation available for PWM to RPM when using 12V?

Thanks

Joshua

@Josh_Huysamen You can edit the code to generate the equation yourself! Click ‘open in playground’ in the upper left, and change occurances of ‘16V’ to ‘12V’, then run the code again. I’ve made a link to the edited playgound after doing the same here.

The resulting equation is:

I was looking for some help with both equations listed here. I am trying to do some line fitting to determine if I can do linear approximations between the points and how large the potential error is. The issue I’m having is plugging in the value for X (RPM) does not give me the stated value for duty cycle. For example plugging in 3200 RPM returns 559788.5092 @ 16V and -60614.08431 @ 12V. Both of these numbers are nowhere close to those listed in the links provided above.

If someone can clarify the discrepancies I’m getting it would be very helpful.

Thankfully

Kas

Hi,

X is PWM, not RPM. Check the charts axis label.

Hello @patrickelectric,

Thank you, I had tried that (using RPM and PWM) but for some reason I didn’t see it correctly. Using fresh eyes and your clarification helped see it correctly.

Thanks

Kas