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One motor is slower... How can I determine if it is a 3510H or 3510?

Jan 16, 2021
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Hey guys, I picked up another Inspire 1 and it showed me a glaring issue with my Inspire 1 Pro.

The Inspire 1 Pro will not turn "flat on axis", ie, it basically wallows when spin on axis in the air.

I landed the aircraft, and started the props on the ground and noticed the back right (with the aircraft facing me) props spinning noticeably slower than the other 3. I took it in the house, pulled the props and started it on the table. I can slow all three "full speed" props but the 4th one (the slow one) with the same amount of pressure stops. It restarts when released, but it is obviously weaker. (Side-Note: I started the V1 and the motors feel exactly like the weaker one on the "Pro")

Also, the ESC cooling fins underneath are warmer on the "slow" motor compared to the rest.

Now, my concern is I was sold this setup second hand as a Inspire 1 Pro setup. It has the X5 gimbal support setup, it also came with a GL658B controller and the "feet extensions". Beyond that I have zero way of knowing if it is an actual "Pro" (ie, v2) setup.

I removed the quick-release hubs and the motors all have 2 holes in them for mounting the prop adapters. There is no writing that states "3510H" or "3510" on them at all. They only have a small ring of print and no Chinese lettering.

Now, the reason I mentioned the other Inspire I just purchased, is because I believe it is a 2014 model V1. It came with 2 GL658A controllers, has a X3 gimbal support and the hatch-pattern carbon fiber arms. On the SD cards and flash drive I got with it it shows dates of 2014/2015 on files (some videos go as late into 2016 and even a 2018 one, but that was it), and the flash drive had the 1.3.x.x controller firmware on it which means they had to update from a 1.1-1.2.x firmware to 1.3 at some point.

Now, I pulled the quick-release adapter off the motors on that one and they look identical to the motors on the "Pro" one I have (no 3510 or 3510H and no Chinese lettering, also 2 mounting holes).

Also, the label inside the battery compartment says T600/1410 FCC ID, the same as the V1 I have.

So, do I "assume" I have the weaker 3510 motors on the "Pro" one? If so I will buy 4 new 3510H motors with ESCs.

If not, then is there any way to be certain that I have 3510H motors and ESCs on the "Pro" one? If I can verify I do I will just order a single 3510H motor and ESC combo. (As I mentioned before, the 3 "full speed" motors seem to be MUCH stronger than the "slow" motor or the motors on the V1 I have, so is that "empirical" enough to say it DOES have the 3510H motors?)

Lastly, in some part listings they show that motor as M4, which is listed as a CW rotation motor, yet when I have the motors running, it is most certainly spinning in a CCW rotation looking at the top of the motor down. Now, does that mean the motors are "spec'd" to run from looking at the back of the motor forward (ie, looking from the ground up), which would mean that it IS a CW rotation motor?

In my "observational" view, it would seem as if the motor in question was replaced with a 3510 motor at some point (would suck to find it was never changed and that DJI shipped it that way) and I am just "correcting" it.

Any and all input would be appreciated.
I might also add it does have a Silver screw portion for the original prop mount (the ones next to it are black with the one across as silver as well).
Per talking to someone who is familiar with these (and repairing them) they verified that it sounds like I have a single 3510 motor on my aircraft.

I guess it will fly like this, but will have less than perfect control and manners. Especially with a X5 hung underneath it.

So I ended up ordering a single 3510H motor with ESC.

Now I need to find a set of foam inserts for the 1345T propellers, as the set that came with the V1 does not have them. Very unsafe to fly without them.
The excess heat in the ESC tells me that you motor may be pulling too much current, which equates to either too much physical resistance (bearings), or electrical resistance (windings). Either way, work will have to be done to either replace or repair the motor. I would Ohm it out to be sure it's not the ESC.

I already have a new motor and esc setup being delivered today.

Luckily I have a place that stocks DJI parts not and hour and a half away from here, so stuff is basically next day.
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Well, replaced the motor and ESC. It still seems to turn "slower" than the others on startup, but it does have more "strength" than the one I replaced on a "grab test".

I flew it and it still rotates around the front right leg vs the center of the aircraft when you spin it on axis. I am going to recalibrate the IMU and take it for a flight.

On the plus side, I also got in my Z3 camera and it works on both the Inspire 1 V1 and the Inspire 1 V2 just fine. It was manufactured in June of 2018, so being a later production model I am hoping it isn't prone to the "issues" the earlier versions had.

It did have to activate the camera when DJI Go 4 came up. I noticed that the Inspire 1 V1 also had to activate the aircraft and the X3 camera once I updated them to the latest firmware.

And, yes, I know, I will be looking at downgrading both the V1 and the V2 to firmware 1.8.x.x along with controller firmware of 1.6.x as soon as I get everything stable and working properly. I just know that DJI will harp about firmware versions if I have any issues (like my bricked X5 camera).

I find it interesting that the X5 is acting in such a way they had to contact engineering to figure out what to do about it since it doesn't move the gimbal at all, and it flashes green to start but then goes dead. I really hope the video I took the day before it bricked helps push them to fix it because of thier firmware vs them trying to say it was a failure, since it was obviously working just fine.
Another update: I redid the IMU calibration and I calibrated the compass. Total success!

It spins on axis nicely, and it is more stable in the air while hovering.

Once I get the X5 camera figured out I will roll back the firmware and be done.
Another update: I redid the IMU calibration and I calibrated the compass. Total success!

It spins on axis nicely, and it is more stable in the air while hovering.

Once I get the X5 camera figured out I will roll back the firmware and be done.

Did the IMU cal fix the slowness of the motor, thus fixing how it us rotating? Or did it just fix how it rotates? Its critical on these to make sure all motors are turning similar rpms. Yes they can compensate, but if all motors aren't balanced (similar rpms and similar temperatures), you can bet on a 'drop from the sky failure.

I purchases an IR temperatures gun (I think it was like $12 U.S. on Amazon, as well as an optical RPM gun (also cheap). Every now and then, after I land, I check the temperature and rpm of all 4 motors. Temp is a key one that can catch a failure before it happens.
Well, per recommendation, I ordered up the remaining 3 motors/esc combos and will redo all to "labeled" 3510H motors.

On the flip side, I will be transplanting the old "unlabeled" motor/esc combos to my Inspire 1 V1. I will watch it to make sure there are no problems. If so I will order up a set of new motor/esc setups for that craft as well.

Now I just need to find a X5 camera mount to put on the V1 as well as a backup to carry the X5 camera.

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