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ESC Frequency-What does it affect??

ESC Frequency-What does it affect??

Old 08-03-2002, 05:57 PM
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Default ESC Frequency-What does it affect??

Anyone can enlighten me on the ESC specification that states the PWM or Switching Frequency.
For example, Futaba MC800C is 3.1KHz.
Does this frequency affect the max speed a motor can be run or does is affect the reaction speed of the ESC to the trottle movement??

Thanks.
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Old 08-03-2002, 09:20 PM
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Novak's site mentions a bit about esc frequencies:
http://www.teamnovak.com/Tech_info/esc_termin/
http://www.rccentral.com/guides.asp?...11&PAGE_NUM=38

For the same esc which can switch frequency, I feel that the lower freq e.g. 2k gives stock motors more punch, and the high one I got 4khz gives a very very smooth, linear throttle reaponse.
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Old 08-04-2002, 05:17 AM
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so that means given a car with everything held constant, a ESC with higher PWM frequency will maximize speed and torque efficiency when compared to another ESC having lower frequency.....
My ESC reads 1KHz...... Dun know if this is causing the lack of speed..... I saw the specs of many high end ESC having greater than 3kHz.......
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Old 08-04-2002, 05:26 AM
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thanks alvin....i read the info on the novak website....
So i think i need a new ESC....
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Old 08-04-2002, 06:05 AM
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Originally posted by kkyeo
thanks alvin....i read the info on the novak website....
So i think i need a new ESC....
KK. i dont think u need a new ESC.. what esc are you using right now??higher freq doesnt always means that it will be better...
althought with higher freq, your throttle response it more linear and u notice that it run much cooler
for stock racing.. most esc on the market is more than enough to hold it ground..unless u are racin mod.. then the higher freq esc will come in play
lack of speed doesnt mean it due to ESC..
alot of factors come into play
comm wear and brushs wear play a part in this aspect of speeds.
Brush sprinsgs,Gear ratio, gear meshing, bearings all these are also a factor when u talk about speed....
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Old 08-04-2002, 09:24 AM
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Well,
Last semester I did a semester project report on ESC. About 30 pages with fonts size 8.

To cut very short......

The freq have to depend on motor's wire's resistance and.............and cannot be measured by a normal multimeter......

Good to start freq. (According to Keyence)

For 23t 1khz
8-9t 4khz

I running 1.5khz but with power limit at 50%

~1-1.5khz is the sweet spot for 23t stock.

And as jack said, generally , higher freq, smoother........


All the above points are based on my little understanding......

Pls correct me on any mistake.
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Old 08-04-2002, 09:43 AM
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Originally posted by Nipple
Well,
Last semester I did a semester project report on ESC. About 30 pages with fonts size 8.

To cut very short......

The freq have to depend on motor's wire's resistance and.............and cannot be measured by a normal multimeter......

Good to start freq. (According to Keyence)

For 23t 1khz
8-9t 4khz

I running 1.5khz but with power limit at 50%

~1-1.5khz is the sweet spot for 23t stock.

And as jack said, generally , higher freq, smoother........


All the above points are based on my little understanding......

Pls correct me on any mistake.
what suject was that??
Power electronics???
you can only measure the freq with the stuff we use for our lab.. right nipple.... need to hook up this and that. and then apply a load.. then read the bloody sine wave ..blah blah blah..
anway...
You dont need hige Freq ESC if u are just racing stock motor..
they dont developed such high resistance ...
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Old 08-05-2002, 12:33 AM
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nipple ..... 1-1.5 khz for stock with 50% trottle limitor ?
stock is already slow as it is and u want 50% llimit to trottle ?

wei any secrects share leh
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Old 08-05-2002, 04:39 AM
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nipple ..... 1-1.5 khz for stock with 50% trottle limitor ?
I power limit not trottle limit.


Well for me......I am not a very good driver. So I power limit to prevent over power and less mistake......In this way I am driving faster by driving slower.



And jack....it is not a subject....but a project.
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Old 08-05-2002, 05:12 AM
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is the inductance the parameter which cannot be measured by the usual multimeters?
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Old 08-05-2002, 05:24 AM
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Some multimeters do measure inductance. Mine doesnt but it measures freq.
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Old 08-05-2002, 06:22 AM
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Originally posted by Jack

.... and then apply a load.. then read the bloody sine wave ....
SINE wave??!?

You're controlling DC, not AC man...

imho the CRO output on the motor wires should be a DC square wave with peak voltage same as input voltage (no power loss except for resistance whilst under load); the FETs should switch on/off sharply at your set frequency.

With pulse width modulation, the width of the on (square) pulse will be proportionate to your throttle eg if 25% power then the FET is on 25% of the time, if full power FETs are on 100%. Peak voltage remains same full V all the time.

"Power" limiters only limit the current flow.

Or, haha... has things changed since I flunked Power 101?
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Old 08-05-2002, 06:56 AM
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hahaha...
maybe that is why i fail that suject
hahahahha
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Old 08-05-2002, 08:11 AM
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is the inductance the parameter which cannot be measured by the usual multimeters?
Inductance == If a coil induces 1v when the current passing through the coil changes at 1 amp/s, the coil has 1 henry ,H, of inductance.

V L = L di/dt



What the F***........

Why make the hobby so difficult......just play lah, I don't think we can feel the diff.....
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Old 08-05-2002, 09:04 AM
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can one lah, even 0.5 degree camber quite a big difference, hehe
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