Fun, Learning, Friendship and Mutual Respect START  HERE

Go Back   HeliFreak > R/C Helicopter Support > 500 Class Electric Helicopters

500 Class Electric Helicopters 500 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.

Thread Tools Display Modes
Old 06-29-2008, 12:37 AM   #1
KDE Direct
Registered Users
Posts: 1,289

Join Date: May 2006
Location: Washington, U.S.A.
Question 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. --
KDE Direct is offline        Reply With Quote
Old 06-29-2008, 12:53 AM   #2
Registered Users
Posts: 2,374

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.
ping is offline        Reply With Quote
Old 06-29-2008, 09:01 AM   #3
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.
Smiky is offline        Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Copyright © 2004-2016 by, LLC except where otherwise indicated. The logo is a trademark of, LLC.