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VESC100/250; RPM Pulse input; antispark precharge

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tobiokanobi
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VESC100/250; RPM Pulse input; antispark precharge

Dear All,

I got kicked into a project where they previously used a 2x(JETI controller and a Motor brushless outrunner (Hemotec 105.20 KV135)). Due to my little experience with the VESC 6 I was able to convince them to go for the VESC 100/250 - because and also of the CAN capabilities.

1) However, my VESC6 didn't really require the Anti-Spark Precharge device - but it seems to be mandatory for the VESC100/250 - is this correct? If yes, TRAMPA seems to have non in the store and due to the though timeline I'd go for the Flipsky? (I got the XT90 Anti-Spark Connectors from Trampa, but didn't find the precharge). Or do you have another advise in this regard?

2) The Motor has an Hall Sensor as RPM sensor, but I guess that this puts out only pulses (for the JETI RPM sensor, so still "Sensorless" and no FOC control). Is it possible to interface this rudiment sensor with the VESC? (without causing much pain and code adjustments?)

I'm happy if you can point me to already answered similar forum questions, I looked a little through the forum but wasn't able to find an answer.

Kind regards,

Tobias

  

 

electricfox
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1.On higher voltages you should always use precharge device or a resistor. Because you are from Austria you can go for a "Sinusleistungssteller AVS" which works up to 14S and even 20S is possible if you buy 2 of them and solder them together as described in their FAQ. I used 2 of them and they work fine!

2.The pulses Sensor wont work but in Vesc-Tool you can use HFI or better VSS for startup, they work very good on most motors.

Regards Oliver

tobiokanobi
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Thanks Oliver!

Sinussteller is a great hint - and a lot cheaper than the Flipsky Antispark Switch. 

Ok. It's not so much about position control at the moment - more like to detect/measure "true RPM" vs. "ERPM". I'm not sure how ERPM may be off from "true RPM" under load condition. (around 3500rpm max).

VSS stands for ?

Kind regards,

Tobias

 

 

electricfox
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You´re Welcome!

It´s easy to calculate, for example here it´s written: https://vesc-project.com/node/183. Vesc-Tool shows you the ERPM in real life data so you can calculate real rpm.

VSS= Vedder Sensorless Startup

Regards Oliver

tobiokanobi
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Okay, perfect! I was aware of the relation between ERPM and RPM (ERPM=RPM*polepair), but not if ERPM is accurate enough when load is applied. 

-Tobias

benjamin
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The ERPM measurement (and by extension RPM) is very accurate on synchronous motors as the rotor has to be tracked without any slip. It will be well within 0.1% or so.

reubarb.scons
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I am using a vesc 100-250 on 22s with simply antispark xt90 connectors and it works perfectly. Just ensure that you plug in the antispark after the bms is enabled (if you have one) 

I am unsure about this hall effect setup that you are working with but my motor came with hall effects. Initially I used it sensorless and the startup was fine as long as you started moving the motor slightly before applying throttle. After setting up the hall effects (which was simply plugging them in and pressing detect) it now works perfectly. 

 

tobiokanobi
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Thank you all for your feedback!