17
votes
Accepted
How can I reverse the direction of a brushless motor?
Swapping any two of the wires connecting a brushless DC motor to its ESC will reverse the direction it spins.
Despite the name BLDC which implies that the motor runs on DC power, each of the three ...
- 5,948
15
votes
Why do brushless motors have 3 wires compared to 2 wires on a brushed motor?
A standard brushed motor has a positive, negative and a commutator that switches the polarity of the rotor.
Conversely, a brushless motor has a multiple of three sets of coils. These coils are ...
- 4,412
14
votes
Accepted
Why does a brushless drone fly longer?
Brushless motors (aka BLDC) are typically[*] more efficient than brushed DC motors. Higher efficiency equates to longer flight times for a same battery pack.
Amongst other reasons:
The inrush ...
- 1,912
14
votes
Accepted
What does KV mean on motors?
Ok, so this could turn into a very long answer!
The short version is, Kv stands for the velocity constant, and it has to do with the rotational velocity it takes to generate one volt of back EMF. ...
- 1,200
13
votes
Accepted
How does one hold the motor bell still when tightening prop nuts?
You know those rubber wristbands that are given out at lots of events?
You can wrap one of those around the motor bell to get better purchase on it, and then torque down the prop nut.
There are also ...
- 4,412
12
votes
What does BEC, SBEC, UBEC, and OPTO mean for brushless motor ESCs?
BEC: Battery-eliminating circuit. Basically just allows you to use the ESC to power the controls circuit, servos, etc. (hence eliminating the need for a battery)
SBEC: Switched battery-eliminating ...
- 121
12
votes
Accepted
Does frequently changing the amount of power to a bldc motor wear it out?
No, changes in speed should have little effect. The only wearing part of a brushless motor is the bearings, which are generally rated for a certain number of rotations and a certain load (and are ...
- 7,003
11
votes
What does KV mean on motors?
KV, often stylized as kV, is a rating for how quickly the motor will rotate for every volt supplied to it. (units of rpm/volt).
However, this is only exactly true ...
- 5,948
10
votes
What happens if i select the wrong number of motor poles in BetaFlight?
This is a setting that is needed for RPM sensing and RPM filtering. An ESC can not sense the RPM of your motors directly, but can sense how often the magnets in the motor bell pass by the coils in its ...
- 2,957
10
votes
Accepted
What is this ring attached to the bottom of this rotor shaft?
That is a circlip (or C-clip) - it looks like it is used here to prevent the shaft from coming out of the bearing.
From the Wikipedia link above:
A circlip (a portmanteau of "circle" and &...
- 5,996
9
votes
Accepted
Can I run two motors off of one ESC?
Technically, you could connect 2 motors, and it will probably work if they're exactly the same size and model, and have identical props on them. However, if the motor-prop combinations are ...
- 2,957
9
votes
What do the numbers mean on a brushless DC motor?
A four-digit number (e.g. 2212)
This number describes the dimensions of the stator inside the motor. The first two digits are the diameter (in mm) and the second two digits are the height (again, in ...
- 5,996
8
votes
Accepted
Why do brushless motors have 3 wires compared to 2 wires on a brushed motor?
TL;DR:
Brushed DC motors have two wires because they require DC current (+VCC and Ground), while brushless motors require more complex driving circuitry which controls the AC current required to ...
- 5,948
8
votes
How can I reverse the direction of a brushless motor?
Swap any two of the wires between the ESC and the motor. Alternatively, use the configurator on your computer for whatever firmware your ESC runs and switch the direction via the software.
For ...
- 4,412
7
votes
What does BEC, SBEC, UBEC, and OPTO mean for brushless motor ESCs?
A BEC is a Battery Eliminator Circuit. This provides a way for you to power other components, such as servos from a source that is more regulated than VBAT.
An SBEC (Switching Battery Eliminator ...
- 4,412
7
votes
Accepted
What does BEC, SBEC, UBEC, and OPTO mean for brushless motor ESCs?
This is an understandably confusing topic because of how the names evolved, and some of those acronyms have become more of a marketing label rather than an actual term. So I'm going to dive a bit ...
- 2,957
6
votes
Accepted
Effect of motor load on ESC?
The primary thing that high torques affect in a brushless motor is the current flowing through. It obviously affects your ESCs, but also the motors themselves: high currents have been known to melt/...
- 2,957
6
votes
Accepted
Difference between iFlight XING-E and XING motors?
The Xing and Xing-E motors have two primary differences, materials used in the bell construction, and the magnets used. The bell is a lower stength 6061 aluminum alloy than what they claim for the ...
- 1,200
6
votes
Accepted
Does the performance of a brushless motor decrease over time?
Like most things, it depends on how you treat it.
As far as I know, you should never need to worry about a brushless motor wearing out, especially for our purposes where we will likely demolish them ...
- 4,412
6
votes
Is there a method to wire a brushless motor to an ESC so it spins in the required direction first time?
Without disassembling the motor, and figuring out how the ESC is designed, there is no other way then simply testing it.
From my experience, the motors spinning clockwise has usually been the ones ...
- 2,644
6
votes
Accepted
Brushless Upgrade for RC Car
The important points are:
The physical size. One of these is labelled 'BL3650', which probably means that the can is 36mm diameter and 50mm long. Of course, it doesn't have to be exactly the same ...
- 7,003
5
votes
How does one hold the motor bell still when tightening prop nuts?
You don't need to hold it with a tool, it's enough to pinch it with your fingers. Using a tool to hold it increases the risk of damaging the threads if you are not careful.
But I can understand if ...
- 2,644
5
votes
How does one hold the motor bell still when tightening prop nuts?
There are commercially-available tools that are designed to grab around the bell using a rubber band, like this one:
However I felt that it's a fair bit too expensive for what it is.
So I made my ...
- 2,957
5
votes
Can I run two motors off of one ESC?
From a technical standpoint it is possible, but there are a number of considerations:
Only need one ESC so lighter
ESC needs to have a higher current rating to fully power the motors
Motors must be ...
- 5,996
5
votes
Accepted
Why do brushless drone motors tend to be more expensive than brushed?
Brushless motors are typically CNC machined for a large part of their manufacturing process. The top part of the bell and bearing race are machined from aluminum. The shafts typically steel or a ...
- 1,200
5
votes
Accepted
Why do most multirotors use outrunner brushless motors?
The difference between outrunner and inrunner BLDC (brushless DC) motors is that an outrunner's rotor is outside the stator while an inrunner's rotor is inside the stator.
(cit.)
In general, ...
- 5,948
5
votes
Accepted
How to measure the RPM of a drone motor using Betaflight?
Bi-directional DShot can help you here. After updating the BLHeli firmware on your BLHeli_32 ESCs to the latest version (support was added only recently) and the firmware on your flight controller to ...
- 5,948
5
votes
Accepted
Grinding sound on FPV motor but no apparent damage
It looks like a bad phase to me. Check the resistance of each phase, wire 1 to wire 2, wire 2 to wire 3, and wire 1 to wire 3. If one of those is much higher resistance or shows no continuity, then ...
- 1,200
5
votes
How can I increase the lifting power?
Faster motors will definitely give you more thrust. However the relationship isn't linear but increases with the square of the speed. So doubling the kV will give you 4 times the power, and going from ...
- 7,003
5
votes
Accepted
Lipo battery with an ESC and a BLDC motor
The motor part number (Turnigy L2210C-1200) tells you two things: The 2210 is the physical size and the 1200 is the Kv rating. The Kv rating tells you the RPM (revolutions per minute) per volt applied....
- 501
Only top scored, non community-wiki answers of a minimum length are eligible