Brushless motor analyzer

[1911Colt]

Why would a person need a brushless motor analyzer? Can you use it to actually tune a motor? Or is it just for testing? I did see that it tests bearings based on the dB level.

I have heard of people "tuning for x amps" but didn't know what it meant.

[scr8p]

I use mine quite a bit. It's not the best one on the market, but it's good enough for me.

[RC10th]

It will tell you how aligned the hall sensors are as well as actual timing since the notches on motors are always way off.

It will also tell you KV at a certain amp draw, most people seem to set the amp draw at 5 - 6 amps to help find the sweet spot which should keep it at a safe-ish temp under race conditions. It won't tell you torque or even the sweet spot so to say so you'll still need to test on the track.

It's not a necessary gadget but does help

[LowClassCC]

It will tell you how aligned the hall sensors are as well as actual timing since the notches on motors are always way off.

It will also tell you KV at a certain amp draw, most people seem to set the amp draw at 5 - 6 amps to help find the sweet spot which should keep it at a safe-ish temp under race conditions. It won't tell you torque or even the sweet spot so to say so you'll still need to test on the track.

It's not a necessary gadget but does help

exactly this ^^^^

Example. A friend had a motor he bought that was supposedly "tuned" which he paid a premium for. At the track he couldn't come close to keeping up with the other racers on the track. He finished last every race with it and was always quite a few laps down from even the DNF racers. I was curious and asked if i could take a look at his car. It was geared to the moon. Something like a 32 pinion with a 69 spur, and was running extremely hot (over 210). I hooked it up to my brushless analyzer and it was only pulling 1.2 amps and the rpm was extremely low. This explained why he had it geared so high and why it was over heating. He was just having to push the motor that hard to try to get it to run. Well I adjusted the motor timing so the motor was pulling 5 amps. The rpm nearly tripled. I tossed on an 86 spur with a 19 pinion. he went out and ran a few laps. On the 7-8 second a lap oval track he dropped his lap times from 13 seconds to 9. and his motor never passed 140 degrees. Geared up a couple more teeth on the pinion and he was running consistent mid 7's per lap. He had been struggling for a couple weeks with that motor. Nearly ready to give up and after this he ended up finishing 3rd overall which was his best finish in 2 years of racing.

IMO a brushless analyzer is a must have tool if you are serious into rc. Being able to tune and very accurately adjust a motor is wonderful. with a simple 17.5 brushless i have seen motors that were the same brand, model, and out of the same lot have 7k rpm difference. the placement of the hall effect sensors can also play a massive roll in how a motor performs. I have seen high end name brand motors have a 8 degrees in variation in the sensors. I and a lowly nobody racer but i wont even run a motor that has more that 2 degrees variation because it makes a huge difference in how the motor runs and how long it lasts.

I will happily lose a race because I suck as a driver. But when you lose because your equipment isnt operating properly just takes the fun out of a day at the track that should be one of the best days of your life.

[1911Colt]

Thanks for the explanations! I appreciate the info. The description on Amain wasn't very informative.

[R6cowboy]

Thanks for the great info fellas. It's good to know even for a non racer as myself.

[1911Colt]

IMO a brushless analyzer is a must have tool if you are serious into rc.

Mine has arrived. Now to figure out how to use it....

Is there a database somewhere that gives an idea what to expect from a particular wind? Or does that just have to come from experience? Finding the sweet spot for a particular motor will be useful, but it would also be nice to know if that motor is a "good one".

I tested a new 21.5. From the factory, it was set at 47 degrees and ran 20,000 RPM pulling 4.4 amps. At 40 degrees, it ran 20,000 but pulled only 3.0 amps. So that is where I left it. At 55 degrees, it ran 21,600 and pulled 5.7 amps. Would that have been a better choice? So far, most of what I have read falls into 1 of 2 camps. One camp says keep bumping the timing until the motor pulls ~6 amps. The other camp says to chart the RPM and Amperage to find a spike in amperage without a corresponding jump in RPM. The point just before the amp jump is the sweet spot.

I also tested a 17.5 of unknown origin. It tested roughly equal to the new 21.5, so I am thinking its best days are over.

The noise feature is cool. I got a 6 db drop on a motor with a single drop of oil! I don't know what the result should have been, but it was cool to see the tool working as advertised. Old dry bearing- 83 dB; oiled- 76 dB. So that was a thing.

[Dangeruss]

I tested a new 21.5. From the factory, it was set at 47 degrees and ran 20,000 RPM pulling 4.4 amps. At 40 degrees, it ran 20,000 but pulled only 3.0 amps. So that is where I left it. At 55 degrees, it ran 21,600 and pulled 5.7 amps. Would that have been a better choice? So far, most of what I have read falls into 1 of 2 camps. One camp says keep bumping the timing until the motor pulls ~6 amps. The other camp says to chart the RPM and Amperage to find a spike in amperage without a corresponding jump in RPM. The point just before the amp jump is the sweet spot.

Depends on what you want to use the motor for. Same RPM at lower amps would yield longer run times. Maximum RPM for track use... diminishing returns and killing a battery before the race ends being your limit there.

[LowClassCC]

IMO a brushless analyzer is a must have tool if you are serious into rc.

Mine has arrived. Now to figure out how to use it....

Is there a database somewhere that gives an idea what to expect from a particular wind? Or does that just have to come from experience? Finding the sweet spot for a particular motor will be useful, but it would also be nice to know if that motor is a "good one".

I tested a new 21.5. From the factory, it was set at 47 degrees and ran 20,000 RPM pulling 4.4 amps. At 40 degrees, it ran 20,000 but pulled only 3.0 amps. So that is where I left it. At 55 degrees, it ran 21,600 and pulled 5.7 amps. Would that have been a better choice? So far, most of what I have read falls into 1 of 2 camps. One camp says keep bumping the timing until the motor pulls ~6 amps. The other camp says to chart the RPM and Amperage to find a spike in amperage without a corresponding jump in RPM. The point just before the amp jump is the sweet spot.

I also tested a 17.5 of unknown origin. It tested roughly equal to the new 21.5, so I am thinking its best days are over.

The noise feature is cool. I got a 6 db drop on a motor with a single drop of oil! I don't know what the result should have been, but it was cool to see the tool working as advertised. Old dry bearing- 83 dB; oiled- 76 dB. So that was a thing.

No big database that I have seen.

Every motor is different. You can test 10 of the same make/model motors all new in box and you will get different results. I normally tune my motors to 5.0 amps. Below 5 amps and the motor is not living up to its ability and you will need to gear higher to keep up with others. This can cause overheating problems. Above 5.0 amps the timing adjustments will net you less for more amps. Not really worth the extra rpm vs heat. Only you can decide what is right for you.

one big thing to look at when testing a motor is the sensors. the closer they are the better. on my race motors I try to keep no more than 2 degrees total spread. but the closer the spread is to zero degrees between them the better. I have found good name brand race motors to be 7 or 8 degrees spread on their sensors. this equals very poor performance.

[RC10th]

Guess how happy I was when I found out my new motor tests like this

The only way to truly test a motor is under load, it's all good to get the crazy free RPM's on the analyzer but can the motor maintain good RPM under load? The analyzer won't tell you that part so it's good to plot a few points on a graph and track test the motor using those points.

[R6cowboy]

Just a suggestion what NOT to do with these motor analyzers. I've ruined two SkyRC motor analyzers with two different Novak Velociti 3.5R motors. During testing them, the current read out in both analyzers worked/fluctuated up to a certain point, after turning the motors up too high the current reading would only read 1.0 amp no matter what motor is tested and does not change/fluctuate under any circumstance. SkyRC tech support denied there was anything wrong with either analyzer and told me they're working just fine And yes I called within the "warranty" time period. So I suggest not testing crazy fast motors such as those.

[1911Colt]

one big thing to look at when testing a motor is the sensors. the closer they are the better. on my race motors I try to keep no more than 2 degrees total spread. but the closer the spread is to zero degrees between them the better. I have found good name brand race motors to be 7 or 8 degrees spread on their sensors. this equals very poor performance.

I am glad you mentioned the sensor placement. Is this just an informational test to help select a good motor, or is there something that can be done to correct badly placed sensors? Are some motors adjustable? On the one motor I disassembled, the sensors were soldered into place, and I seriously doubt that I could remove and more accurately re-position them except through trial and error. Maybe Jeff can cut us a jig to position them perfectly

Is the board replaceable? Do folks save the better aligned sensor boards and use them in other motors?

[1911Colt]

Just a suggestion what NOT to do with these motor analyzers.

The hottest motors I have are 7.5. I should be safe testing those right? Maybe I test those last just in case

[LowClassCC]

one big thing to look at when testing a motor is the sensors. the closer they are the better. on my race motors I try to keep no more than 2 degrees total spread. but the closer the spread is to zero degrees between them the better. I have found good name brand race motors to be 7 or 8 degrees spread on their sensors. this equals very poor performance.

I am glad you mentioned the sensor placement. Is this just an informational test to help select a good motor, or is there something that can be done to correct badly placed sensors? Are some motors adjustable? On the one motor I disassembled, the sensors were soldered into place, and I seriously doubt that I could remove and more accurately re-position them except through trial and error. Maybe Jeff can cut us a jig to position them perfectly

Is the board replaceable? Do folks save the better aligned sensor boards and use them in other motors?

Sensor placement is mostly informative. Now there are some guys that have de-soldered and re-positioned them. I am not one of those skilled individuals.

You can swap boards between motors of the same brand/series. I don't go through enough motors to need to do this.

[LowClassCC]

Just a suggestion what NOT to do with these motor analyzers. I've ruined two SkyRC motor analyzers with two different Novak Velociti 3.5R motors. During testing them, the current read out in both analyzers worked/fluctuated up to a certain point, after turning the motors up too high the current reading would only read 1.0 amp no matter what motor is tested and does not change/fluctuate under any circumstance. SkyRC tech support denied there was anything wrong with either analyzer and told me they're working just fine And yes I called within the "warranty" time period. So I suggest not testing crazy fast motors such as those.

I've had zero issues using the skyrc motor analyzer with my novak 5.5 or any other extreme motors so far. maybe I have just been lucky or you may have just been unlucky.