EV drive motor wave-form

[nickb2]

Cuz the one I tried to jerry rig, was all over the place, was not getting mirror image on wave back handshake. Even whe I knew car was fine, had to be settings or tool. It was tool.

So, again, what type of scope are you using? Can you give me make and model, knowing you, the is a high end counter top thing, not made for autmotive, and now your asking what setting and scales to use. Shyte, your better off asking the other nick on hat one. Me, and he are in trump la la land right now. I almost want to hold his hand.

 

[nickb2]

oops, should have said

He and I

 

[billr]

The scope is a TEK (Tektronix) TDS 2024, a general-purpose scope. I am connecting to two of the motor phase wires, reading voltage/current to one phase. For current I used a 1/2 ohm resistor in series with the phase wiring and read voltage across that. Yes, the scope is isolated from the grounding of the AC mains (battery-powered would be no better). This VFD has a bus voltage of 335 VDC, maybe not as high as some EVs, but in the same neighborhood!

Triggering of the scope is probably my main issue. The carrier being PWMed is about 6000 Hz but the max freq of the sine created is 60 Hz. If I sync on the sine, I can see nothing but fuzz in that carrier, little clue what the PWM really looks like. The waves I have seen as examples online show a sine being made up of only a few carrier pulses, so fairly easy to see. Not so when the carrier is 100X as fast as the fastest the sine will be!

 

[nickb2]

Yeah, you have to fine tune that down. The unit you have, as you know, is not automotive frenziedly. But try to lurk here,

The data base will expand as we go.

https://www.picoauto.com/library/waveform-library

 

[nickb2]

This is very off topic, but a reality of trade. I tried to show how to time a four cam police interceptor. I do those in my sleep, and yes, that was my horn tooting.

Car won't pull, I was not there that day, gone deciphering these really cool binaries. As a soldier, I will fix, buddy from work is on vacay, he started job, but has to keeps kids, wife is on paid vacay in cuba. F

I know he f uped the crank. How many teethe off? I don;t think the 3.7 is that interference, I could see synch off, told guy he did it wrong, now he is scared. I told him, no sweat man, you are a valuable part of team, don't let this get you down, next time, we will time it together.

 

[nickb2]

This is just for informational, but knowing WHAT a gateway is crucial in EV's as a diagnostic approach.

I feel a need to disclaimer myself often. I am not a teacher, I am a student. So all this is just from experience, and what I find pertinant for what I need to do.

So when the module and teacher said pay attention, I did. I had scoped some can lines thru gareways before, but they are not called gateways per say. Inference here is like this.

Back in the day, the instrument cluster on mopar, WAS the gateway. It decided who got what info. This is just an example. I have seen gateway in caddy roof module, send can bus along to whole back unit. If one speaks Chinese to a french guy, weird things happen.

Now, on the EV's, they actually to have a "labeled" gateway. Alot of them three or 4. The bolt has four I have found so far.

So scoping that is a first step in case you get a U code of any form.

 

[nickb2]

@billr if your still lurking, lurk here, lots of nice stuff to read,

https://gm-volt.com/forum/showthrea...018-Volt-amp-2017-Bolt-via-K56-gateway-module

 

[nickb2]

Of important note, gm updated lock out from 3 sec to 30 sec, very substantial upgrade, give breathing room for other high speed to process.

Now I know I wrote that wrong so I will copy paste or screen shot what I think I read, and let you all decide if I read it wrong.