PWM Switching Rate? Please Explain...

KDE Direct · 06-29-2008, 12:37 AM

Hey Guys -

Could someone please explain to me the importance of PWM switching rate and how it applies to power/efficiency with the motor? Essentially, here's my primary reason:

With the Scorpion HK-3026-1400 motor in the TREX 500, I was originally using the Scorpion ESC programmed to 8 kHz for the PWM rate. I've since switched to the Phoenix 80 ESC, which is programmed to 13 kHz for the PWM rate. There is now an option to use 8 kHz, but I don't know what the advantage of going to a lower or higher PWM rate is??? Does a higher PWM rate produce more power at a cost of efficiency, or vice versus?

Could someone please explain and help out? Thanks to everyone for their support!

ping · 06-29-2008, 12:53 AM

The short explanation is the efficiency of your motor will go up with increased PWM setting. Don't go higher than 13khz or you risk burning up that motor.

Smiky · 06-29-2008, 09:01 AM

The 8 KHz PWM frequency is the rate at which the ESC chops up the phase signal going to the motor in order to slow it down. The ESC fires as fast as the motor is turning, but the amount of power that goes into each cycle is controlled by the PWM modulation of the signal.

06-29-2008, 12:37 AM	#1
KDE Direct Registered Users Join Date: May 2006 Location: Washington, U.S.A.	PWM Switching Rate? Please Explain... Hey Guys - Could someone please explain to me the importance of PWM switching rate and how it applies to power/efficiency with the motor? Essentially, here's my primary reason: With the Scorpion HK-3026-1400 motor in the TREX 500, I was originally using the Scorpion ESC programmed to 8 kHz for the PWM rate. I've since switched to the Phoenix 80 ESC, which is programmed to 13 kHz for the PWM rate. There is now an option to use 8 kHz, but I don't know what the advantage of going to a lower or higher PWM rate is??? Does a higher PWM rate produce more power at a cost of efficiency, or vice versus? Could someone please explain and help out? Thanks to everyone for their support! __________________ -- KDE Direct, Inc. --

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06-29-2008, 12:53 AM	#2
ping Registered Users Join Date: Jul 2005 Location: Indiana	The short explanation is the efficiency of your motor will go up with increased PWM setting. Don't go higher than 13khz or you risk burning up that motor.

06-29-2008, 09:01 AM	#3
Smiky Registered Users My HF Map location Join Date: Jan 2008	The 8 KHz PWM frequency is the rate at which the ESC chops up the phase signal going to the motor in order to slow it down. The ESC fires as fast as the motor is turning, but the amount of power that goes into each cycle is controlled by the PWM modulation of the signal.