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Which to believe, manufacturer inductance spec or VESC autodetection?

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kubark42
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Which to believe, manufacturer inductance spec or VESC autodetection?

I have a VESC 100/250 connected to a Geiger HPD20. The Geiger documentation lists the phase-to-phase inductance as 8.7uH:

Screen Shot 2021-09-29 at 09.49.15.png

The autodetection routine claculates the single phase inductance at around 1.45uH. Dividing the published phase-to-phase inductance in half we get 4.35uH, which is still ~3x larger than the autodetected parameter.

I have every reason to believe that Geiger has done a thorough job of characterizing the motor. They deliver a high quality product which is used in manned aviation, a field which heavily disincentivizes gross  parameter errors. However, that doesn't mean I'm comparing apples to apples. VESC Tool says that the inductance is the average of the `q` and `d` currents, and I don't know if that is a one-to-one mapping to the phase-to-phase inductance which Geiger reports.

Which value should I use?

 

electricfox
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Why using such a big motor with such a small Controller like Vesc 100/250? It will be hard to reach more than 10-14KW continuous without lots of cooling. Also its hard to set up this kind of motor. You need a lot of testing and tweaking values. I experienced this on such kind of motors already. The detection on such of kind of motors is always bad with Vesc Controllers, thats why even Benjamin Vedder is using an LCR Meter like DER EE DE-5000. In the datasheet its not written at which frequency the inductance is measured. The frequency is changing the value a lot. I measured my motors at 100kHz with the DE-5000 which measured values made the motor run significantly better. Your measured values are not fine. You should try a value close to 8,7uH. Be careful and don´t use higher switching frequency over 30kHz. There have been lots of Vescs 100/250 killed on such motors. Benjamin will share a video how to set up motors like those. Check the Collection of Burned 100/250 Vesc´s thread. Regards Oliver

kubark42
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Why using such a big motor with such a small Controller like Vesc 100/250? It will be hard to reach more than 10-14KW continuous without lots of cooling. 

It's a 20kW max motor, so the 25kW peak controller is a good paper fit for prototyping. The application is aviation, so cooling is easy to come by. There are a lot of variables in this equation and right now I'm at the point where it's important to start getting empirical data.

I have a Geiger ESC which I can use to compare to the VESC. I am very impressed by the VESC firmware and would like to move to theat platform IFF I can get it tuned acceptably. The ability to servo the motor is very important to my application, which involves retracting the prop once the plane is at altitude.

There have been lots of Vescs 100/250 killed on such motors. Benjamin will share a video how to set up motors like those. Check the Collection of Burned 100/250 Vesc´s thread. Regards Oliver

That thread is great, thanks for the link. Really happy I'm using a lab supply and running low voltage to start. Right now I'm just playing around with the setup to explore its low speed, low power characteristics. It'll be a while before it gets given a power supply with some ooomph.

kubark42
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Fixed in https://vesc-project.com/node/3225, as documented in https://vesc-project.com/node/3225#comment-8374 the VESC now reports 3.5mH.