KV rating on brushless

[2revo1maxx]

Ok I've always been a nitro guy but I'm going to get a brushless rig soon. What's the difference between sensored systems and non sensored systems? Also what does the kv rating refer to?

 

[TheyDontWantMusic]

kv is how many rpm the motor does per volt..

my buggy is a 3300kv motor, off an 11.1volt lipo, while my mates is a 5500kv motor off only 7.4volts...

so, he has lower voltage, but his motor still spins faster

 

[Rolex]

Excellent info! I've been meaning to ask that myself. Thanks.

 

[abadk9420]

Well you got the answer for the Kv thing, as to the other part of your question a sensored ESC/Motor system allows the ESC to know where the rotor is at all times inside of the motor and generally has less of a problem with cogging, but also requires another set of wires that run from the ESC to the motor, A sensorless system does not have this feature and is more prone to cogging. Cogging is where the motor kind of gets stuck and is more of a problem a slow speeds.

 

[2revo1maxx]

Sweet I get it for the most part.....so i'm gonna run a 7.4 volt battery on my mini lst2 would a 6800kv system be ok?

 

[neobart]

Higher Kv motors are more sensitive to gearing, so a low Kv motor can easily be made to go as fast as a high Kv motor, only it will run cooler and have better runtime. Only problem is added battery weight.

 

[hamz9561]

I run a 6800kv motor and a 2s LiPo in my RC-18r. Plenty of torque and speed. It's a good overall setup for bashing.

 

[2revo1maxx]

Yeah that sounds good I'm thinking about something "middle of the road....ish". Don't wanna get crazy I just know I'll get sick of the mini lst2 in stock form, always gotta go faster. "Gimmie a lawn mower I'll speed it up".

 

[Metalhead Matt]

Look into the vicious diff set up. The stock ones are plastic. A brushless system will kill them fast. I bought a mini lst 2. I gave it away. The idler gear in the tranny is plastic, too. No metal upgrade available. Rc18's are where it's at.

 

[MotoGod]

Another point to note, at least with 8th scale brushless, is that battery voltage plays a part in how fast the motor spins as well.

I run a Castle MMM 2650kv combo in my 1/8th buggy on a 3s LIPO. That brings me to @ 32K RPMS, which is considered to be the "sweet" (28K - 32K) spot for most motors. If I run it on a 4s LIPO then I bump it up to @ 42K RPMs which just turns it into a ballistic missile with no controls ;-)

There is a chart out there somewhere with RPMs based on voltage. I can't find the darn thing at the moment though!

*edit* - Bah...someone already said this! lol

 

[2revo1maxx]

Look into the vicious diff set up. The stock ones are plastic. A brushless system will kill them fast. I bought a mini lst 2. I gave it away. The idler gear in the tranny is plastic, too. No metal upgrade available. Rc18's are where it's at.

The website says the ring and pinion are metal. Are you saying the spiders are plastic? That would be ***!! Either way it was 100 bucks brand new and I got a 2.4 ghz radio for my revo out of the deal. I just hope my traxxas reciever will fit on the mini.

 

[Metalhead Matt]

I actually had the Raminator. It's a lst 2 with only one motor. Unless they changed them since spring, they have plastic ring and pinions. That idler gears a bitch, too, but I installed a center diff eliminator. A monster truck that can't wheelie? I didn't like that. Stock, with a 1500mah dynomite nimh, it held up pretty good. Still pretty slow, though.