OldNick

OK. What does it all mean, in relation to RC cars. I am interested in brushless motors.

As the title says.....

I actually want to change my ESC. The one I have is non-programmable and not very satisfactory, considering other have variable max power, variable braking, variable reverse etc.

But I need to know how to decide what ESC to get, based on all of the parameters of a motor. Which matter and which don't? Which mean what etc.

As a former electrician, I understand the theory in basics, but I would be interested in the state of play regarding RC stuff.

Do ESC's have different frequencies? I assume that would affect how it drove a motor..

Whatever. I had a look around but found little, and the best looking link I was not allowed into![]

Thanks for any help.

Nick

ehroof

Turns is how many time the "wire" is wrapped around, the less turns the more torque and rpm you will have but the battery will not last as long.

The esc senses the kv of a motor and adjusts accordingly, its the motor that has the differnt kv. Depending on the unit you have, sensored or sensorless is how it reads the kv of the motor. I like sensored since it reads it thru a sensor cable and you dont have to worry about the motor chugging at low speeds since sensorless cant really read the kv until there are some rpm's

OldNick

Wow! I am glad I asked. This is a long way from fifty cycle scientist stuff!


I got the turns bit. Less turn, higher current..more power...less battery life.

The sensored vs sensorless bit is interesting. I have seen my Bront shudder as I ease on the throttle....then leap into action.

What does KV actually mean? To me it means KiloVolt, and that is obviously ridiculous.

Is this all digital stuff? I am quite able to take on huge amounts of data and actually love doing that sort of thing, to the point of being a PITA.

Sorry. It's like guys who love Nitro because they can fiddle with engines!

Are there recommended places I can go to start ferreting about?


Nick

pede_187

Kv is the RPM per volt.

OldNick

OK. Thanks. But isn't there something in there that controls the speed of the motor using the frequency of the signal from the ESC?

ehroof

it reads the rpm of the motor. Thats why a sensor system is better, its more efficent, it can read the low rpm's.

Redharris

Nick......

Brushless Motors are SORT of like Stepper Motors (in computer hard drives and VCR's), but with only 3 Poles.....

The ESC takes the D.C. Voltage from the Battery and converts it to a 3 phase alternating current that is fed into the motor Stator.
This in turn causes a Rotating Magnetic field that acts upon the ROTOR (which is noting more than a Magnet) and causes it to turn.

There is Control Circuitry in the ESC for forward ,reverse, speed ,brake, etc....
There is Really no such thing as an UNSENSORED Brushless Motor (in RC). Sensoring is basically just FEEDBACK from motor to ESC.
Even "Un Sensored" ESC/Motors have and use Feedback (they couldnt work without it). Its just that they dont use SEPERATE wires/circuit to do the Sensoring,,,,,The motor is SENSORED through the 3 Motor cables.

Eddie is Right though,,,,,Systems with Separate Sensor cables are more Efficient and sensitive and thus,,,,work a lot more smoothly under certain circumstances.

ehroof

yeah, what Rich said

lol, i didnt want to get too technical

OldNick

NAH! That's great! I will happily soak up whatever you can throw at me! I am really interested. If you guys have had enough of answering, then site pointer would do. As I said I tried bit was not in much luck.

I had it figured that it was basically a 3 phase motor, and not actually a stepper. You cannot feel the stepper "shudder" if you turn the motor by hand.

Is it back EMF that is sensed to control the power given to the motor?

Does the ESC use frequency to control speed, or volts? If it's volts, what is the

Is an ESC that is for "5.5T and upward" simply able to send enough current to 5.5T motor without blowing up? This would mean that there is a standard voltage that comes from ESC's, no matter what make....?

I will have to think about whether I just get an ESC or a sensed system. At the moment the weak point in the overall car-driver thing is the driver. These things really go! and I am not quite up to it yet. I dread to think what they must be like when guys use 11Volt LiPo's.

Nick

Redharris

The Most important thing to remember is to MATCH all your Components......

You want to make sure the Motor will not Draw more amps than the ESC is rated for.......

You want to make sure you dont supply more Voltage than the ESC is capable of Handling.......

After all that,,,,you need to make sure your Gearing (pinon, spur gear, tire diameter) is such that the motor/esc will not overheat and Die.....

The EASIEST way to do that is to look at an entire SYSTEM.......and buy That.

For You Truck,,,,,The Himoto Brushless system should work great!

Another good one would be the Castle Sidewinder(1/10 sport) motor/esc......

If you Really want to explore the Details and Technicalities of Brushless Systems,,,,RCU has a Forum full of Folks that might actually have ALL your answers....Try [link=http://www.rcuniverse.com/forum/forumid_147/tt.htm]HERE.[/link]

OldNick

OK. Thanks. I might duck across there.

Nick