Lacroix Motors vs Unity flaky motor temperature noise

How-Tos & Esk8 mechanics
#1

everyone says the sensors suck on lacroix motors and to depin them. but is it the unity?

this is some weird data.

  1. note that both motors temperature noise goes the same directions at the same time.
  2. there’s a couple idle times in there ( duty cycle 0 ) where the temperature reading suddenly drops after seemingly being artificially high.

fw 5.02
Unity.
Lacroix 6389 motors.

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notes on avoiding faults:

  • I managed to not trigger faults while collecting this data by using freesk8 app to hack the motor temp cutoff end to 200c
  • others depin
  • others change the thermisitor beta value so the readings are artificallly low and never fault.
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#2

Someone send this man a stormcore to definitively answer the question! The fact that the noise seems to be the same on both motors is a great observation. Could be that the motor current, which is the same, is affecting things, or it could actually be the ESC…

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#3

whats the beta value on the thermistor in motor vs. setting?

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#4

settings:
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idk, what’s in the motor. or how to find out.

#5

Thats a problem :slight_smile:

#6

I had the same problem. Solution was to use braided cable shielding on temp sensor cable.

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FAULT_CODE_OVER_TEMP_MOTOR (feat crash at 47kph)
#7

not following … ?

ooh … do you have pictures? I was hoping to try this never got around to it.

#8

Some examples on different applications:
Twisting cables and keeping them as far away as possible from phasewires helps too.

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#9

You need to use the right beta value if you want accuracy.

Either ask the manufaturer what the betavalue of the thermistor is or swap it out for a known value.

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#10

sure.
are you saying it’s the wrong beta value? afaik, it’s from lacroix that way and is correct. (but could have changed somewhere in it’s life. )

afaik, wrong beta value won’t cause wild swings… and filtering out the wild swings the numbers look reasonable.

#11

4100 is apparently the default in vesc_tool. so that’s sus.
I’m told 3380 is the right value.

not expecting that to have anything to do with the wild swings shown above though.

update: yeah two other lacroix motors are set to 3380.

so nice catch @linsus thanks.

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#12

I have a special tool that’s fixes this issue that I got on AliExpress

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#13

Do you have a link or a name for this tool?

#14
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#15

Oh LOL I thought you were referring to some sort of electrical tool to test the beta value :rofl:

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#16

Hopefully its improves abit atleast :slight_smile:

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