V12

iTrader: (1)

Hmm there are a number of different settings but which one are the factory settings. I canīt see anything whatīs named as factory or default setting.

KO PROPO Staff

rcnewb2004- I don't see the difference either. The older VFS-2000 had an on resistance of 0.00042 and Japan tells me that the newer VFS-1 is lower. That is all that they will say. When it starts to get this low, Can you really tell the difference? The solder build-up in your wires from hard wiring your batteries to your esc will yeild more resistance over time.

V12- Look at the first set of data. The title is "Factory Default Settings" in blue. You may have to refresh you browser.

V12

iTrader: (1)

KO PROPO Staff
Thanks. Refreshing the browser did help!

rcnewb2004

KO Propo Member - That's why I am a vfs-1 believer for its customablility and variable frequency.

I believe the underlying principles of all modern speedos are basically the same, except the VFS has the trigger-sensitive variable frequency, which currently other speedos such as the futaba mc800c can only operate at steady 1 freq at a time.

However, I would like to know a little bit about the technology behind the modern speedo.

I understand that the escs today use pwm to control a motor's speed... That way no external resistance is required to create a voltage drop.

But what is happening (to the voltage curves) when a person pushes on the throttle on a spd control that only operates at 1 frequency?

How bout on the VFS-1? What happens to the voltage on an esc that has variable frequencies?

How does this result in the Low freq = more punch and High freq = more speed that is talked about on the KO webpages?

Finally, how does this all tie in with motor characteristics?

I know i am sailing abit away from vfs here, but if I want to be a full believer of the product, I want to understand fully, at least in theory what the vfs does to accomplish its task. Please smack me with some technical details.


I wish I had an oscilloscope... sigh.....

KO PROPO Staff

rcnewb2004- The following link give a very good in-depth description on how this works. http://www.joliettech.com/what_is_a_...ency_drive.htm

V12

iTrader: (1)

I think some brands donīt post internal resistance as there are fake specs with some ESCīs. Another thing is most brands are just posting specs of the FETīs in use but this is just half the story. A lot of the internal resistance can be lost or gained in the quality of the PCB and this is as important as the FETs.

rcnewb2004

Thanks KO Propo Staff! I think there has been too many ppl trying to muck up what exactly is an esc so this is a good chance for me to clear a few things in my head.

v12- Excellent point. Not to mention that FETs can have very different resistance numbers under different temperatures. Now it all makes sense. FET resistances are basically meaningless unless conditions are specified.

Most ppl just read numbers, and some of these esc manufacturers are just here to exploit them.

rcnewb2004

KO Prop Member:
(Mind if I call you Robert?)
I just have one little problem.... those pics on the link you posted,.... they suck.... they are so small.. and combined w/ my poor vision, doesn't help much...

u think u have other links that could be helpful? sorry to bother. thank you for your help.

tranced

Hey I have a VFS-2000J.. wondering if the default profile loaded on it is suitable for stock?

If it's not, what type of profile is default? Thanks!

Hebiki

iTrader: (26)

default profile is 17 all the way across. should be okay for stock... but its preferable if you load some of the profile esp. designed for stock motors (search on this thread..or check the Ko site)

rcnewb2004

Got a Question:
which one will run hotter (the temperature of the ESC) on a 19T?

30,30,30,30,30.....

or

5,5,5,5,5,5,5,5....??

V12

iTrader: (1)

I think the ESC shouldnīt run hot with a 19T but using a higher frequency will result in higher temperature because of the higher switching losses. So from your examples the 30,30,30,30,30.....

rcnewb2004

cause I have been practicing with a 19t and nearly dumping my packs. i am running the original hara 2.1 profile (originally designed for modified) so the freq. settings are very high... and the temperature of the esc (with addition of heat sink) is around 50 degrees celcius. That worried me.... but now I am glad to hear that perhaps it is due to high frequency settings that my esc is getting very hot.

V12

iTrader: (1)

Maybe it has to do with anything else as wrong gearratio or high drag in the drivetrain of the car. Meaning bad/damaged bearings or anything like that. I would remove the pinion and check if the car really runs free.

rcnewb2004

maybe you are right... i will give that a go. running a 19T, 1:5.42 ratio...