Help trying to get my LDU to spin for the first time

[spiff]

Hi Everyone,
I'm reaching out to get some troubleshooting tips on getting my LDU too spin on low voltage. Here's where I've gotten to:
- Openinverter board connected to LDU powers up fine and I can get to the home page.
- Using a 30V 10A bench power supply for HV testing and a freshly charged car battery for 12V supply
- Set UCDNOM to 0 and UDCSW at 20
- Precharge and main contactors connected and working properly (turning on and off at the right times)
- After the precharge and momentarily connecting the start pin, I'm showing 30V at the HV motor leads so I know it's getting power.
- Calibrated the throttle pedal and can map/see the values responding properly when I plot and try to push the pedal
- Tried removing the encoder and starting in manual mode starting at 5 for "fslipspnt" and increasing in increments of 5 up to 100

Motor does not spin for any of this.

Are there values I should be specifically looking at in the parameters to see if everything has been done properly or if something's not working? Any other suggestions?

[Bigpie]

Make sure to watch this if you haven't, it could help avoid an expensive mistake.

[catphish]

Motor does not spin for any of this.

Is it drawing any current? It might simply be that it's not pulling enough power to get spinning.

[Peter]

Hi spiff. If all your connections etc are ok as per Damiens video then you could try increasing Boost. When I first started I could not get my motor to run with a low voltage source, increasing Boost solved that but its only a suggestion ok. I guess you have direction fwd or rev enabled ?

[spiff]

Thanks everyone for the responses. I did recheck/test everything as per the video. All initial meter readings on the inverter were fine.
The board is getting power and when I turn the axles manually and plot the speed it registers so I know the encoder wiring and connections are also good.
Again the contactor circuits (pre-charge and main) are working as I can hear them clicking on and off at the right times, and I do see 30V at the motor leads after "start" is pressed and the opmode is in "run". Direction is engaged (pin 7) showing forward.

Thank you for the tip on Boost. I will try that next. Hoping to update this thread with success!

[spiff]

SUCCESS!!!!
After months of waiting for parts, replacing bearings and seals and then wiring everything up, the used motor that I bought 5 months ago that I had no idea whether is functional, actually spins!

Two things I ended up doing:
1. Needed to increase the boost value from default is 1700 to 10,000.
2. When I did that the axles started moving but very slowly and in a stuttering way. Even though I was using a stock tesla wire harness connecting the 23-pin port to the 4-pin encoder port, it looks like pins 2 and 3 needed to be swapped. Once I did that the axles responded smoothly to pedal inputs!

Thank you all. I'd like to contribute my own thoughts to the FAQ as there's a few things that I struggled with that may help others. Do I need special access? Where is the best spot... On here or github?

[johu]

Great to hear!

Maybe pinswapping of two PWM phases should be ported to async code, too. Should make encoder wire swapping redundant, right?

[asavage]

I'd like to contribute my own thoughts to the FAQ as there's a few things that I struggled with that may help others. Do I need special access? Where is the best spot... On here or github?

Perhaps the Wiki?

https://openinverter.org/wiki/Tesla_Model_S/X_Large_Drive_Unit_(%22LDU%22)#Encoder_Issues

To edit the Wiki, all you need is to be logged in with your usual OI credentials; no special access needed.