Brushless motor timing accuracy
 

Hi,
I have a SkyRC BL motor analyzer and out of curiosity I checked my Hobbywing 6.5T G3. The mechanical timing was set at 30 degrees. With the analyzer, it was average 23 degrees. A 26, B 21 and C 23. Is this "normal" accuracy for a high end motor? Average 7 degrees off, and the phases not even...
Thanks

Nope, looks like you might have a bad sensor board, or anaylzer:)

Hm motor is new... What is the normal accuracy for the phases? All the same?

Don't depend on a cheap analyzer.

Since I've used my analyzer on a crap load of motors, I know that mine works to some degree. I personally won't use a sensor board if it's more than 2 degrees out of phase. The worse motor I've bought has been out by 4 deg, but others have seen worse.

Is this with a gforce analyser or a Trinity motolyser? I am considering buying the gforce.

Take the sensor board out and re-assamble it again, the value can be changed and maybe more equal.

Yea, whenever you have a motor with a sensor board out by 4 degrees or more, you sell it to me. :D

Just kidding

This is true. I just bought a V16 R1 motor from a friend and it was out by 6 degrees. Took it apart, cleaned it, reassembled and viola, 2 degrees. Please don't ask me why.

Yeah, you can definitely change the sensors by how tight you do the screws and the order.

The Hobbywing is not a "high end motor". It doesn't matter if the physical timing of the board doesn't line up with the corresponding marks on the can. What matters is how symmetrical the sensors are to one another. With this being a brand new motor assembled by someone putting it together as quickly as possible, you might want to take the motor apart and see if taking your time to carefully tighten the sensor assembly screws. A more expensive motor has better quality control (usually).

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The mechanical reading on the end bell almost never matches up with the true digital reading that is averaged across all 3 phases. I use the same SkyRC Analyzer too, I only use the timing reading on the analyzer to help me determine if the gap is properly shimmed between the rotor and the sensor board. The goal is to get all 3 phase readings within 1° of each other, then you know that you have properly set the gap. First I check there is at least 0.1mm gap using a spare spacer. Main reason you don't want the rotor too close is that it can hit the sensor board in a bad crash and damage it. I have seen local racers destroy their sensor board on the very first battery pack on a brand new motor. First thing I ask is if they shimmed their rotor? The answer is always, shim the what? I try to keep the same amount of shims but will swap out a 0.5mm shim with a 0.3mm and 0.2mm shim to give me wiggle room, it can take me up to 8 times of playing around with spacing the shims until I get good reading but it is well worth the hassle because this will not only save your sensor board but will also maximize the efficiency of your motor. Then I focus on setting the timing which is completely arbitrary, I go off the manufacturer's recommended current draw. I run Trinity motors and they recommend setting timing to 5.6A draw to get max power without wasting energy in the form of heat. What that means is that anything above 5.6A won't make the motor go any faster, it will just make it run hotter and draw extra current from the battery with that extra loss in heat. In contrast, Tekin drivers have been recommending 3.2A for their motors, every brand is different and every motor can have different timing readings, which will also change over time as the magnet fades, you'll need to periodically adjust the timing to reset it back to your target current draw, etc..

Ok thanks
It seems like the G3 sensor is a part of the endbell and there is only screw to loosen to adjust timing. The endbells are secured with 3 screws.

What is a "high end" motor for 1/10 off-road racing? I feel the Hobbywing is expensive enough:)

My G3 have a lot of end play both directions. I will try to shim it closer to the sensors. I can feel the rotor "settles" in the middle as it is per now. If I push the rotor closer to the sensor, it will return back again when I release. If I shim the rotor as close to the sensor as possible, it is not centered in the magnetic field anymore... Is that ok, or will it lower the performance and kill the bearing at the pinion side because of the thrust forces?
Thanks

https://www.rcgroups.com/forums/show...0#post40391914I don't go off of any "feel", I let the analyzer tell me by making very slight adjustments of moving the shims around.. if I go too far in one direction and the 3 phases go farther apart, then I know I'm shimming the rotor in the wrong direction, then I'll double back until I get all 3 phases within 1° of each other, then the shimming process is complete :)

Most Trinity motors I have tuned tend to have very little gap between the rotor and sensor board, I generally increase the gap, but here is a case with a Novak motor that I recently purchased where the gap was way too big and I had to shim it closer to the sensor board... in this case the end bell was fixed timing which started out at 18°, but by the time I finished shimming the timing jumped up to 20° which made it far more efficient and deliver more power to allow me to gear up an extra tooth ;)

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