Brushless Motor and ESC question!

[Rhumba555]

So I'm nearing the end of my HDX300 build (sort of) and have a question. I have the Sonix 18A Brushless ESC and it has 3 blue wires to be connected to the brushless motor. The motor wires are black, red and white. How do I know which color goes to which wire on the ESC? I don't want to burn it up by coinnecting it wrong. Thanks.

[jgoodwin]

If it is brushless (with three wires, I bet it is) hook them up. Then if it turn the wrong way reverse only two of the wires. this works on 90%+ of the BL motors. I think there are really high end ones with more , uh, points (can't remember) that this does not work on. You won't blow the motor though. (no guarantees implied :-)
-J

[skunkworx]

Hook them up inline with each other, the black wire into the ESC comes out the other side (blue) which you hook up to the black wire (-) on the motor. The red wire is the same way. The center wire goes to the white wire in your motor. I believe this is a 'common' wire because these motors are basically 3-phase.. For some reason the manufacturer didn't want to 'color code' the wires. Nothin' to freak about.

The ESC should be marked with (+) & (-) coming from the battery. On the other side of the ESC are a dot, 'motor', and another dot with the 3 blue wires coming out to join to the motor. If I lost you, let me know and I'll try to clarify (or someone else here will help you!). Hope this helps!

[Pinecone]

skunkworx, with a brushless motor all the wires are connected together, and they are symmetrical. When the thing is first wound, there are 6 wires coming out, they get conencted in one of two ways to make 3 wires. There is no difference between the three.

Just hook up any one of each of the 3 wires on the motor to any one of the 3 wires on the ESC, and keep doing this until all three are hooked up. Color has nothing to do with anyting. If it turns backwards, disconnect any two wires and swap them.

A motor with more than 3 wires is likely to have sensors and require special ESCs to wrok with them.

If you are interested the 2 ways to hook the 6 wires up are Y or Delta. If you ahve wires 1, 2, and 3, and each has an end A and B.

For Y you hook up all there B ends together and the A ends are the ones you hook to the ESC.

For a Delta wind, you hook up 1B to 2A, 2B to 3A, 3B to 1A. And each connection point is what is hooked to the ESC.

About the only company that tells you what type of connection they use is Neu, and that is the Y or D at the end of the motor designation.

For more info, check out GoBrushless.com and StrongRCmotors.com They both sell kits and parts to wind your own motors. A lot of fun, and a teaches you a lot.

[skunkworx]

Thank you Pinecone. Your response is duly noted, I was trying to simplify the answer without overdoing it. I'm assuming the motor came with the kit and is a WYE connection motor. True they are symmetrical, but it's easier matching pos. to pos., neg. to neg. etc...
Good knowledge but a bit much to swallow for someone who might not know all the physics and science behind all the things we use.

[Pinecone]

There is NO POSITIVE OR NEGATIVE. That does not simplifly it confuses.

All three wires are the same. And for purposes of motor to ESC connection Y or Delta doesn't matter.

SIMPLE ANSWER:

Connect the three wires from the ESC to the three wires from the motor IN ANY ORDER. If the motor turns backwards, swap any TWO connections PERIOD.

[skunkworx]

Not that I want to argue, but, Riddle me this?; If you have no POS or NEG, then how is commutation achieved? Magic smoke? It has to start somewhere doesn't it?

Yes it is true that you only have to reverse any two leads to get it to spin the opposite direction. Blah, Blah, Blah...Simple enough, (Kicking a dead horse on this) but here's the reason why...
Each drive phase consists of 1 motor terminal driven high, one motor terminal driven low, and one motor terminal free floating. Pull-up and pull-down resistors, along with dead time control keep any two from being energized on the same level (high or low) at any given time, thus making it spin (the ESC only pushes current 1 way), and the spinning is controlled by pulse width modulation (explained below) which is created by your ESC with feedback. Switching two wires sends the current the other way.

Good enough answer for ya' there Pinecone?

The rest of this is FYI for those who'd like to know it.

Depending on what feedback system the motor/speed controller uses (Hall's sensor or sensorless), the ESC first detects rotor position, then energizes the PHASES (you got 3 to choose from!) that will produce the largest amounts of torque. The rotor travels 60 electrical degrees per commutation step. The appropriate stator current path is activated when the rotor is 120 degrees from alignment with the corresonding stator magnetic field, and then deactivated when the rotor is 60 degrees from alignment, at which time the next circuit is activated and the process repeats. (All of this can be shown on a chart or graph, but you gotta go find 'em yourself! They give you a visual confirmation of timing and phase changes during the process. After the motor is spinning enough, back electromotive force (BEMF) is sensed and is used to control the PWM which commands the duty cycle of the driver MOSFETs (Metal-oxide-semiconductor field effect transistor).They work kinda like the timed spark on a car engine :D and in turn make the motor go faster or slower (Hooray we have speed control! :D).

In the undying words of our friend Finless, "I hope this was helpful and enjoy!" :glasses2:

[HeliDan]

Is this not just a simple 3-phase AC power source? Sounds like it to me. If so there are three sinewaves each is 120 degrees out of phase with the next.

When dealing with three phase power there is no neutral (ones idea of ground or return or negative). The current flow is because the three phases are out of phase with each other, meaning a difference of potential, thus current flow.

[skunkworx]

This is little bit of good 'ol DC brushless motor theory. A square wave or sawtooth wave is created by the transistors and MOSFETS,s (basically they act as solid state switches) which are fed a commutation code by the PWM. The MOSFET drivers then feed a 'pulse' to the motor and it spins. AC is pretty much the same exept they run on a sinusoidal wave 120 degrees out of phase with one another. one is at full positive or Vmax, one is at neutral or 0.0V and the third is at full negative Vmin depending on the total supply voltage. I don't have any graphs handy to give a visual comparison of the two but I'm sure you only have dig a little t find them. Gotta love Google! :D

www1.microchip.com/downloads/en/AppNotes/00857a.pdf here's a good little reference that's easy to read. It gets a little boring but if you are interested, it will show you all the stuff I just talked about. It doesn't have a very good graph to show the input pulses so you might try looking up DC brushless motor theory or something like that. Figure 2 is an ok representaion, but can be a little confusing for those who don't know how to read them. The books I usually look at are reeeaaalllly boring, so I didn't want to cite what they had to say.

[HeliDan]

your link does not seem to work. I tried removing the '1' from the 'www', still did not work

[skunkworx]

Hmmm...try Googling Speed Controllers, the first one that comes up is a really good site as well. It has a good chart on the input wave and torque curve. See the MOSFET heat dissipation part that is a lot lower down the page. There are a lot of formulas in there that are ued to prove the theories, but just look at the plain english stuff first. I'll re-post the other one because it really explains the topic well.

[Pinecone]

The problem is that every one of the three terminals are both positive and negative at different times depending on where the stator is in relation to the magnets. So telling someone to hook up positive and negative doesn't help. It is like telling someone to hook US 220 by hooking up a positive and negative, or even a hot and a neutral (for those that don't know, US 220 power is two 110 legs out of phase to produce 220 line to line, both are hot).

IMO it would be best if all motors and ESCs came with all three wires the same color.

Yes, these are exactly the same as a 3 phase AC electric motor, except the ESC produces a pulsed DC instead of sine wave AC, and the phasing/frequency of the pulsed DC is variable to give us variable speed (3 phase AC motors run at a speed based on the line frequency).

[HeliDan]

The problem is that every one of the three terminals are both positive and negative at different times depending on where the stator is in relation to the magnets. So telling someone to hook up positive and negative doesn't help. It is like telling someone to hook US 220 by hooking up a positive and negative, or even a hot and a neutral (for those that don't know, US 220 power is two 110 legs out of phase to produce 220 line to line, both are hot).

IMO it would be best if all motors and ESCs came with all three wires the same color.

Yes, these are exactly the same as a 3 phase AC electric motor, except the ESC produces a pulsed DC instead of sine wave AC, and the phasing/frequency of the pulsed DC is variable to give us variable speed (3 phase AC motors run at a speed based on the line frequency).

Thats what I thought. thanx pinecone.

[skunkworx]

I see what you mean. Definately agree with you on the color thing. They should do that on the motors as well.

[Pinecone]

Yeah, actually LESS confusing to not color code. :)

[Rhumba555]

Uhm...Thanks a lot guys...I..uh..think I got it...my motor is up and running.