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Simple Bench Test for Inspire 1 ESC/Motor Assemblies?

Discussion in 'Inspire 1 Help' started by Tq2Jetman, Sep 25, 2016.

  1. Tq2Jetman

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    I have read many posts here about ESC errors and DJI Inspire 1 ESC/Motor issues.

    What I have not come across is a simple bench test one can do on removed ESC/Motor assemblies.

    Ie: I have a qty of ESC/Motor assemblies but want to know if they are serviceable before I go through the process of installation into a DJI Inspire 1 itself. Also the units currently installed it would seem have a problem but which one?

    At the moment I am in the process of repairing a crashed Inspire 1 myself. I cannot get the motors to start and I have changed two ESC/Motor assemblies. I get the DJI Go App ESC warning message and the only other thing that jumps out at me is the camera (X3) moves slightly as I attempt a start (Left RC stick).

    IMU, Compass and RC are all calibrated and OK. Camera works. GPS works. No landing gear lights illuminate. Rear light flickers green.

    So has any Guru out there devised a simple test box or has a wiring diagram for one where we can plug in a ESC/Motor assembly and test the little sucker?
     
  2. jasonthomson

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    I don't know of a way to bench test. The rear lights flicker and then ESC error comes on screen?
    Could be a bad motor wire. The ESC may be good but as soon as power is sent to the motor it shuts down.
    When my ESC was bad, as soon as I put the battery in and powered on the craft. The led on the landing foot came on yellow.
     
  3. calde315

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    Really the only way I've done it is with a working inspire. Unfortunately there is too much going on to just simply hook up voltage I'm afraid.
     
  4. The Editor

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    There is no 'simple' comprehensive bench test you can do unless you have an understanding of PWM and three phase drive output (which brushless motors are).
    However, what you can do is attach the esc to a battery supply and take the controller input and connect it to a simple Futaba style RX (do not use S-BUS though, use dedicated channel outputs).
    Connect your three phase esc o/p to a known good motor and then you should be able to adjust the speed using the remote that is bound to the RX. You will be able to ramp up and down the speed of the motor from the remote.
    Keep doing this for each motor. If you get one that doesn't work you have a bad motor.
    Conversely if you swap the esc out each time and use a good motor, when the combination doesn't work, you have a bad esc.
    The Inspire esc's are nothing special other than reasonably fast switching. However they do run proprietary firmware so nothing like Simon K or the likes. You will need to fully disconnect each esc/motor combination in order to run the tests above.
    Additionally the esc's will need to see 100% stick throw for them to arm so make sure you do not have dual rates or travel limits programmed into your Transmitter, or any mixes set that will average out a 100% output on the throttle channel.
     
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  5. emtea

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    Out of curiosity, anyone know what the RPM range of our motors are?
     
  6. The Editor

    The Editor Moderator
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    Unloaded or loaded?

    Unloaded as per the motors KV rating so for 3510/350 350rpm per volt (roughly and not allowing for back emf) So for a nominal 22.2 v unloaded will be around 7,770rpm. :)
     
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  7. emtea

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    Ah okay, that's neat, did not know you could calculate it that way, thanks Editor!
     
  8. Tq2Jetman

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    Hi, its been quite a few months since my original post but I have not had time to progress my issue.
    I do not claim to have an understanding of "PWM and three phase drive output", but might know someone who does. That being the case what words of wisdom could you share for someone with the knowledge?
    Also the DJI Inspire 1 ESC wiring loom sockets are a bit of a mystery (To me anyway). ie: The small 3 pin one I know feeds the Landing Gear LED light but the larger 5 pin socket obviously allows signals to flow to/from the Aircraft's NAV unit computer, but it is not obvious what wire in the loom does what (One ESC/Motor loom is coloured light brown, yellow, red, black, red. The other ESC/Motor on same side is coloured light brown, yellow, brown, black, brown). And based on your previous advice which ones I should hook up to in order the perform your "Basic" tests.

    With ZERO help from DJI themselves my nearly repaired Inspire 1 remains unable to start. Sure I could just buy four new ESC/Motor assemblies and hopefully it will be fixed. In fact even if I wanted to buy these direct from DJI I have just last week been advised they do not sell them. I can source them on eBay of course. I would also be willing to send all my ESCs and motors to a shop that could bench test each, but if said shop's method of fixing is to simply replace (DJI SOP) then that is a waste of time and $'s.

    I would also bet my last $ I am not the only Inspire 1 operator out there that would like to see a way forward on this issue.

    Thanks for your feedback to date.
     
  9. Kiwi53

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    Tq2Jetman, I have a set of Inspire V2 motors and ESC's on my bench and likewise cannot for the darned life of me find a way to bench test them. I have a totally destroyed I2 so have all the harnesses etc on hand. I understand pretty much what makes these things tick and my idea was to take three wires that are obviously the PWM feed to the ESC and connect them to servo tester. I tried that today and not even a hint of success or even smoke. I use a bench power supply to feed the ESC so I can easily monitor any over current or short circuits. From the four I tried to test today one has a constant 5 amp load so I figure that one is fried. (This machine spent three days on the bottom of a lake) The other three do not draw so much as a milliamp. I will try to post some photos of my setup tomorrow as some one might be able to enlighten me as to what those extra two wires do that also go to the 5 pin plug. This cannot be rocket science. There has to be a simple way to bench test the ESC and motor combo. But those two additional wires to the ESC plug have me snookered right now. Surely someone knows what they do and how I can trick the ESC into thinking its powered up and healthy.
     
  10. Tq2Jetman

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    Kiwi53, I agree, but those with more knowledge on these matters do not. DJI show absolutely "No interest". I have an inventor/IT/Engineer Guru friend in USA (I live in Western Australia) working on a solution for me (ie: Build a simple bench tester for ESC/Motor Assemblies). My current solution was eventually to buy qty 4 new ESC/Motor assy's, replace all on my Inspire 1 V2 (Which I was repairing), get it flying, then using one motor connection point, test each of my suspect ESC/Motor assy's.

    I had initially purchased 2 new motors (Based purely on external scratches (Before I figured out I couldn't test the ESC as stand-alone items) and 4 used (Untested but purported by the seller to be OK) ESC/Motor Assy's. So all up I had qty 12 ESC/Motor Assy's and 2 new motors.

    Outcome so far is:

    a) Qty 4 new ESC/Motor Assy's installed, tested, flown - Satis.
    b) Qty 2 used ESC's deemed U/S. (Using repaired Insp 1 as a test bed).
    c) Qty 3 used ESC/Motor Assy's checked serviceable (Using repaired Insp 1 as a test bed).
    d) Qty 2 new motors still OK
    e) Qty 2 used Motors (Removed from ESC and tested using a locally built RC set-up) Satis
    f) Qty 2 used ESC's (Removed from Motors) not yet tested
    g) Qty 1 used ESC/Motor assy not yet tested

    But for the lack of a simple bench tester a VERY expensive way to figure out what was originally wrong.

    Isn't hindsight a wonderful thing. The repair is very much not cost effective in my case. It might have been had I been able to test each ESC/Motor assy before I started buying spares.

    And I am still very peed off about DJI position.
    1. They do not sell the ESC/Motor assy's to the general public (They say)
    2. They do not make the ESC as a separate part. They do for other drones in their fleet.
    3. They will not release data on how to test ESC.
    4. They will accept the drone back for repair through their system but their fix is to replace the complete aircraft at current retail price. And don't get me started on the X5 camera repairs (Lack thereof and the weak gimbal design, which can break way too easily. All fine if covered by warranty but useless outside of that).

    I doubt any of my rant is useful to you, unless you are looking for some spares. If and when I get the bench tester unit idea fixed I will re-post.
     
  11. Kiwi53

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    Tq2Jetman,
    Many thanks and I actually agree with most of your points. I did find a place in England that sold just the ESC but they are out of stock so a bit like a hip pocket in a singlet. If you dig deep into the DJI system the ESC's are listed as replaceable parts in their inventory. A whopping $14 each. The Pommie lads wanted 37 quid each. Geezus thats squeezing the lemon a bit much.

    X5 repairs. Well I must have been one lucky bugger. We totaled the Inspire 1 V1 and bust up the gimbal really bad. I sent it back in and they rebuilt it for $350. I was freaking ecstatic about that. When I purchased the V2 submarine for a really good price it came with an X5R that I thought would be Ok for parts. I fired it up after drying it out in rice for a week and it worked. Gimbal arm was knackered but geez $450 later I have a fully reconned X5R hanging off the belly. The SSD cards hurt like kick in the nuts to buy though.

    Because I believe nothing is junk until proven otherwise I used the motor ESC packages from the tree-d V1 in the V2 frame and now have that close to working. The swim seems to have dicked the battery master board that sits just in front of where the battery slots in. I got a brand new one from Hong Kong for $60 and I think we will have ignition and take off this weekend.

    Sure I have now backward engineered it into a V1 but if its performs OK then I will shout it a new set of motors and ESC's from the V2 and Bob should be my Uncle again.

    However Im not giving up on finding out how to test those bloody ESC's. I have a motor test bench and that side of it is a POP. The ESC should be easily controlled by feeding it with a PWM signal from a simple servo tester. I mean the retract motor works on a 5V battery and servo tester so they are easy as to test. The ESC surely uses PWM but their are two extra wires to that 5 pin plug. That feeds back to the flight controller so it must be an inbuilt health checker. Thats where the ESC warnings, no propellor warning etc etc comes from. If I can find a way to trick that into thinking its OK then I can test these bloody things.

    Gidday mate from Chile. A long way from WA....
     
  12. Tq2Jetman

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    Kiwi53, And there I was thinking I was chatting to someone living in "The land of the long white cloud" (New Zealand).

    My X5 has been around the world chasing a fix. First port of call was the Australian DJI repair (Parts changers Inc.) shop in Melbourne. Their solution, buy a new body (I didn't send them the lens). I rejected that and got it returned. Next try was a USA based drone repair shop that viewed all the photos and reckoned they had the correct magic wand. So off it went. After quite a few chases I finally got it back in an assembled condition. Hooked it up to my new Inspire 1 and it just will not stop wobbling and eventually max stops the gimbal motor. Spoke to USA shop at length. Tried adjusting the magnetic nut. Stil no joy.

    Two questions if I may:

    1. Where did you send your camera to for such cost-effective repairs?
    2. Any ideas re my repaired X5?
    3.. How sure are you the ESC's that were out of stock in UK were correct for you bird? (I like the price though).
    4. Where in DJI system did you find the ESC $14 beasts?
     
  13. Kiwi53

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    I sent them both to the DJI repair center in Los Angeles US of A. I used the online repair request form they have on the DJI site and they send you a customer repair tracking number. Drop said camera in the box (No lens, no cards, no extras as they don't want them and they will likely forget to return them anyway. Just ship to them and be patient. It took about three weeks for them to turn each one. When you go into requesting a repair you need to click a few boxes to say your in the USA but thats all.

    I gave up playing with gimbals as they are just so bloody finicky to do anything with. I see that when DJI do the repair on the camera they then actually fly it to test it then do a full QC after the acid test. I have nothing but praise for them in that respect.

    The ESC's were genuine and a wee birdy in DJI told me the ESC from the V1 and the V2 are the same.

    Follow this link.( DJI Repair Service Center ) Put in your model and version and in the list you will see an item half way down called motor driver board. That has to be the ESC. You may need to create your own account but that wont spam the hell out of you or cost you. Click the link Accessory Price Enquiry
     
  14. Kiwi53

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  15. Kiwi53

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    Tq2Jetman, I have stuck this up on YouTube to see if I can get any bites. If I do I will keep you in the loop. Im stuffed if I can figure out how to bench test them eh..

     
  16. jlrsn

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    Kiwi53, have you found out anything new regarding your quest for ESC troubleshooting?
     
  17. Kiwi53

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    jlrsn, How I wish. Its like the question has been thrown into a black hole. Whatever goes in will never come out. Fingers crossed that someone in the far off universe knows and will fluke the link and come up with some answers.
     
  18. Kiwi53

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    Still not any closer to finding a way to test these darned ESC units but slowly but surely I will crack it. In the specs they talk about the sinusoidal wave pattern they use to control the motors but that is a bit of a wild card as the E600 motor packages you buy are also the same and are controlled from a simple PWM controller. I have a set of them and they test out like any other unit. I have now removed the motors from the ESC and tested them with an impedance meter. Pretty basic stuff and then I ran the motors up using an old HK speed controller to make sure they run perfectly. So far I have four good motors. By using a variable bench power control I have three ESC units that do not draw a single milliamp when hooked up to 18 volts. One ESC draws nearly 6 amps so I figure it may have a dicked capacitor on it. Attached video shows the motor test and me waffling on. It might help someone one day.

     
  19. Kiwi53

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    Inspire ESC-1.jpg Inspire ESC-2.jpg Inspire ESC-3.jpg Inspire ESC-4.jpg

    Well I guess even if I had found a way to test I was pushing pooh up hill with a pointed stick so to speak. Finally broke out the mighty MACRO lens as I had missed these tell tale signs of expensive smoke. I figure this happened when it hit the water as there is no other simple explanation. No doubt now the only cure is four new ESC's but I might as well get motor and ESC combo kits and be done with it.
     
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