ESC Basics: Part 1 - PPM vs PWM

In this video, we look at the basic signals an ESC deals with, PWM and PPM.
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[@Kibinas]

Really useful video for such narrow but widely used topic 👍

[@spacemonkey986]

Great video!.... what are the difference between older ESC's that use classic PWM connected to a FC like the DJI Naza M V2 vs current more advanced ESC's and 4 in 1's connected to a betaflight configurable FC?

[@tmlrobotics5446]

I learned a lot from this one! I like the white board setup you have been using.

[@TeamPanicRobotics]

Thanks! its something i've seen a few people discussing, so I figured I'd start a series on how an ESC works. All going well, I'll keep this series going until I've built an ESC on camera

[@tmlrobotics5446]

That would be great. I am looking forward to seeing how to works.

[@billysallerlei]

PPM in RC istn't Pulse Position, RC uses the Pulse Pause Modulation. This signal is what comes from the Radio, it includes all channels in series. PWM includes only the information for 1 Channel. The Reciever decodes the PPM signal into 8 or more different PWM signals. Or am I completly wrong?

[@EleanorPeterson]

My mind's giving you a hug; my brain's giving you a slap. ;-)

[@decode110]

So ggooddddd

[@DarianCabot]

What defines the start of the period for PPM? Is there a separate sync pulse signal or something that is referenced for timing?

[@TeamPanicRobotics]

As far as I know there is no sync pulse

[@rva1945]

Pulse width from a FlySky I6 tx inPPM ranges from 600 to 1600 microseconds, is that normal?

[@TeamPanicRobotics]

that does not sound normal

[@mietekgpz]

Wrong, voltage is the same in PWM

[@TeamPanicRobotics]

yes the maximum volatage is the same
But if the PWM frequency is higher then the component (motor, led, speaker, e.c.t.) can react, the component "sees" and reacts to a lower voltage
Thats literally the purpose of PWM, to control the speed of a motor, volume of a speaker and brightness of an LED in software

[@mietekgpz]

@@TeamPanicRobotics No! If so you would have lower torques on lower speedes because od lower voltage. The whole purpose of PWM is to keep voltage at maximum rated level, do you can achieve maximum torque with less speed. If it would lower the voltage, you could just simply adjust the voltage to control speed. But then you would loose a lot of torque, and in some cases the motor wouldnt even start at lower rpms.

[@TeamPanicRobotics]

You have it backwards
Torque is a function of current, not voltage: acim.nidec.com/drives/control-techniques/news-and-media/blog/technical/current-power-and-torque-in-variable-speed-drives#:~:text=For%20a%20given%20motor%20flux,flux%20and%20the%20armature%20current.
Speed is a function of voltage, which is what PWM does, it changes the voltage "experienced" by modulating how much "on" time the motor sees, hence making the motor turn at a speed equivalent to % on time*input voltage
Where you may have gotten confused, is that PWM allows full current to flow for the given input voltage and winding resistance of the motor allowing for higher torque then if you fed the motor with a lower voltage supply or limited the voltage with resisters (this latter case would greatly inhibit the current flow, causing very low torque)