Brushless motor and ESC

[goddy888]

I want to use a brushless motor in my King Hauler. What should i be looking for? Any particular Kv, turns or amps? And also what about ESC?

Thanks.

[SonoranWraith]

Not that you can't run brushless, but you don't need it. Speed isn't important and the costs are more but getting better. In any case, if you run a brushless motor you have to have a brushless ESC.

[Espeefan]

The best motors for this kind of application will have a pretty low Kv rating. Sometimes it's hard to find motors with a low enough Kv, that will bolt right up, or even fit at all. Some of the very low Kv motors are so large they just won't fit. The options are not as plentiful, when you want a brushless motor. Look more at the out-runner type motors, as they usually have a lower Kv rating, but not always. In-runners are traditionally easier to bolt up, but run faster.

Figure out what sort of battery pack(s) you want to run, and then figure out what motor Kv you need. In general, a motor that spins 6,000 - 8,000 rpm at full throttle will get you in the scale speed neighborhood. For example, if you want to run 12 volts, divide 6,000 rpm by 12 and that will give you the Kv rating you need. It would be about 500. If can't find a motor that comes close, then pick one that is closest, or if you can't do that plan on adding an auxilliary gear reduction or reduction box to a faster motor. You'll need to calculate the motor speed, based on the reduction, so you end up with a good scale speed.

Current really isn't something you'll need to worry about with a truck. Most trucks are geared so low, you won't even come close to maxing out a brushless motor or brushless ESC.

Turns is more for brushed motors, as brushless motors use Kv ratings more often, but sometimes they use both. I would rather watch the Kv rating, rather then turns, simply because not all motors of the same turns run the same Kv rating.

If you need some examples of brushless motors you can run, check out these -

http://holmeshobbies.com/home.php?cat=19

I am sure there are others out there, but many require some modifications to bolt up like a 540 or 550 can motor. Most will not just bolt up. Many have larger motor shafts too. So standard pinions don't fit.

Is it worth the hassle? Maybe. Most scale trucks are not power hungry. Most brushed set-ups run smoother and offer better throttle control then brushless set-ups. Sometimes brushless systems feel like an on/off switch at the especially slow speeds. Sensored brushless systems are closer to brushed low speed throttle control, but I still think brushed motors give better, smoother response.

[GerryK]

Look under General discussion
Brushless motor for 7.2 volts
Mar 18 2011

Gerry

[goddy888]

Thanks guys for all the info.

[gun]

i read on here alot about how many turns the motors are but i dont understand is a 65 turn stronger than a 55 turn motor

[Thorsteenster]

You could use a Novak Goat system, tons o torque and probably more wheel speed than you'd ever need.

[gun]

dont really want more speed from what i understand the trucks are way to fast out of the box so i want to slow it way way down !!

[Thorsteenster]

Get the Goat with the 21.5 than instead of 18.5. Plus brushless motors are rated by KV, basically how many RPMs the motor will turn per given volt. So you could feed it 6V instead of 7.2v for example to tune it to max speed you want to hit.

And when I said plenty of wheel speed, that's for a crawler, not by any means compared to racing or bashing brushless systems.

[gun]

ok im with you now that we are talking about a crawler . thanks for the help ive learned more the last ten min. with your help and didnt have to research all night

[Thorsteenster]

If you told me that beforehand, I woulda made you search......
lol

[Espeefan]

i read on here alot about how many turns the motors are but i dont understand is a 65 turn stronger than a 55 turn motor

As far as brushed motors go, the more turns you have, the more torque that motor will make, but it will also spin slower, and consume less current, which relates to longer runtimes. So a 65 turn motor should be more powerful then a 55 turn motor, but sometimes that's not always the case. Motors that are mass produced and machine wound have some variables. No two motors are identical and sometimes you get a ringer. One that seems to have more power then another. The most torquey motors are those that are hand wound by a person. A hand wound 55 turn motor will probably have more torque then a machine wound 65 turn motor. The difference is hand wound motors have tighter wraps, and the tighter the winds are, the more efficient the motor is too. Performance increases all across the board. Motors with fewer turns are high horsepower motors, but they need to spin fast to make the power, and they consume more current.

Brushless motors are totally different animals. Best to stick to the Kv ratings to determine the speeds they will run, on any given voltage. Just about any good brushless motor, designed for rock crawling, will work good for a scale semi truck too.