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ABS_OVER_CURRENT Error


#1

(copied from my post on vedder.se forums)

Hi guys,

I managed to get everything working (homemade vesc), the board was moving with the remote (nothing on it), but when I put my foot on it and applied a small pressure, I found some lag in (that’s what I thought) the command transmission. And then nothing, even with my foot off. The red led was blinking and the board not moving anymore.

I connected it back to the computer and I had a ABS_OVER_CURRENT (-136amps something like that). I rebooted the VESC, seemed to be ok (no error showing up and correct current values), but now the motor doesn’t move anymore :frowning:

It’s like the VESC “see” it moving (the pikes is when I hit the gaz but the motor doesn’t move):


My motor conf:


When I run a motor detection it doesn’t move the motor and I get bad detection but no error in the real time data.
So close to ride it… :cry:

Is it bad doctor ?


#2

Some news : I saw that there were a possibility that the phases could be shorted, so I disassembled the motor but everything looked fine.

I tried again and now I can get the motor moving a little bit. It just clicks and raises immediately an ABS_OVER_CURRENT.

I checked my shunt they seem fine (added some tin to be sure). Also today (I don’t remember changing anything) the real time data look like crap:

My DRV is brand new, the motor worked few minutes perfectly (but with no load). I guess the problem came when it started to draw more amps.

Don’t know where to look, I’m desperate… :disappointed:


#3

Post some high res photos and we can take a look to see if something is out of order and can be cleaned up or resoldered.


#4

Do you have some picture? Maybe it the Ground plane of the DRV that is not correctly solder.


#5

Make sure you didn’t short out the shunts on themselves, or check if the shunts sense are well soldered


#6

I checked the shunt and added more tin, don’t know how it could come from it. I’ll check the shunt line to the drv.

And the DRV pad is good, I made sure to solder it correctly (it’s my second DRV, I blew the first one either because I soldered a diode the way around or because the pad wasn’t correctly connected).

Here are the pics:

Could it come from the big caps ? I’m not sure the soldering is perfect (I’ll fix it tomorrow).

Thanks a lot for your help :relaxed:


#7

Other thing you can do is check the continuity of the drain-source of the fet to see if you have one that is blown. Same thing for gate-drain, must be high impedance.


#8

@Blasto : I checked the shunt and they seem to be “shorted on themselves” as you said. I think my multimeter is no accurate enough and see it as a continuous line (here in red). Is it normal or should it see a resistance between the red dots ?

I don’t know what you mean by the drain-source and gate-drain. Could you please be more specific ?

Thanks :slight_smile:


#9

Thats normal, accros the shunt there’s 5mOhm of resistance, you won’t be able to measure that with any multimeter. What i mean when i say short themselves, is the small leg is short with the big leg. But i dont think this is the case.


#10

Ok, but what about drain-source and gate-drain ?


#11

Need to look in my old threads, i explained this already w some fancy ms paint pictures. Hold on


#12

Do you have the title of the topic ? I looked to your old posts but didn’t find your piece of art :confused:


#13

I had this issue when I had bad connections from the FETs to the Motor. It was evident when I inspected the plugs and they had burn marks from the arcing electricity. Perhaps ensure that you have a solid connection that can pass high amperage/voltage through?


#14

Are these pins soldered together?


#15

Yes, these are normal


#16

Well, I checked my soldering and didn’t see any burnt marks :confused:
And yes, the two pins are connected together


#17

Maybe those will help you for checking the mosfet (Like @Blasto suggest)


#18

You should get the same respond from the multimeter as testing a regular diode


#19

I tested as you showed. Here are the results:
-in position 1 (picture 1) I have 0.431v value
-in position 2 (picture 2) I have 0.572v value

If I put the probes in the opposte way, I do have OL but not instantly, it “slowly” raise up until it displays OL.

However, in resistor mode, I can read the same value in both position (reversing the probes) :confused: Not good right ?
Values:
-in position 1: 41kOhms for the for the two fets of the right, 5MOhms for the third one (the one tested on the picture).
-in position 2: 38kOhms for all fets.

Those values are the same for the fets on the other side of the PCB.


#20

these value seem ok, the most important is you don’t have any short.