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Help calibrating a hub motor

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Tin_Man_0
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Help calibrating a hub motor

I have an ebike hub motor, direct drive, and for some reason the wizard isn't calibrating it correctly. It sounds like a Harly motorcycle engine when running and has no power or speed. I know next to nothing about these types of motors, or electronics for that matter. I've attached some screenshots of my manually and slowly rotating the wheel. I can put ones of it running "full speed" if that's better. From looking at the charts, I suspect something to do with the rotor position or the sensors might be off...

 

...Damn, looks like I can't just upload images?? and a photobucket doesn't work either?? Here are some links instead. Any help would be appreciated.

https://pasteboard.co/IMXrOFA.jpg

https://pasteboard.co/IMYqAri.jpg

https://pasteboard.co/IMYqiv2.jpg

frank
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Try to run it without sensors first. You need to figure out if you have a sensor or detection issue. 

Stupidspencer
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Frank is right, try unplugging the sensor harness and see if it runs smooth (but it may need help starting). If there is no sensor feedback, the controller will automatically run in sensorless mode, even if its set to use hall sensors.

Judging by the position graph, I don't think all three of your motor's hall sensors are connected. The hall sensors output a digital signal that changes from 0 volts (logic 0) to 3.3 or 5 volts (logic 1) as the magnetic field moving over the sensor changes polarity. The sensors are spaced such that their logic signals produce six different states equally spaced over a single ELECTRICAL revolution, or ERPM. There are only six states because the three hall states will never be all high or all low. The cominations are: 001, 010, 100, 011, 101, 110. These six states indicate discrete positions within an electrical revolution, and those positions are all the controller needs to know to commutate the motor. When you look at the position graph in VESC tool, you should be able to see these six states of the sensors.

My motor position graph above shows 7 electrical revolutions. You can see that the controller interprets the six states of the halls as angular positions within 1 electrical rev.

In case you don't know, the number of ERPMs in one physical rotation of the motor depends on how many magnets there are. For example: if your motor has 14 magnets, there are 7 pole pairs (1 north pole, 1 south pole), and thus 1 rotation of the motor will produce 7 electrical revolutions.

So my advice would be to check your sensor harness and make sure all the wires have continuity from end to end. If that checks out, test the output states of the sensors by connecting an LED between the GND pin and each H1 H2 and H3. LEDs only work one way, so put the short lead to the GND pin and the long lead to the hall signal pins. You need to do this with the VESC powered on and connected to the motor sensors so that they receive power and will power the LED. You can just stick the leads of the LED into the back of the sensor connector on the VESC. If you have the sensor voltage switch set to 5v you may need to either use a 5v white LED, or put a resistor in series so the LED doesn't burn out. As you rotate the motor, you should see the LED turn on and off. 

Tin_Man_0
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Actually, I figured out what the problem was. Hopefully this will help out any other beginners. This device, like all other ESCs are high current devices, meaning, it's not just good enough that the device turn on and attempt to run. You have to have good SOLID connections at all steps of the way. Just crimping on come connectors isn't going to cut it. Nice thick solder points will go a long way from saving you headaches, not just the motor leads, the sensors too. I had 3 wires crimped and all 3 needed to be re-done with solid solder points and that finally allowed the wizard to properly calibrate the motor, same goes for the "app" device, in my case a simple throttle handle. I had to solder those straight onto the pins and make sure they were held firmly with some hot glue slathered all over. Now it's working like it should, but I'd still like some advice on how to calibrate ramp up speeds and that kind of stuff. The default seems to be set to a safe mild slow start.

Stupidspencer
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I don't know which control app you are using (probably ADC), but for a PPM RC controller, you would change the highlighted values to change the forward and braking ramp times. The same ramp settings can also be found on the settings pages for ADC and VESC remote apps.

 

Edit:  Note that the ramping times refer to how quickly the controller responds to changes in throttle commands. But if you are using a current control mode, this ramp time does not mean jamming the throttle would cause the motor to reach full RPM in 0.4 seconds (as I have mine set). It refers to how long it takes for the controller to increase the current to full current. However, In duty cycle control mode the ramp times DO refer to the amount of time to reach full RPM.

vadicus
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I have been testing my design with large hub and inrunners.

What I found and what has been confirmed by other people on the forum, is that the inductance and/or flux linkage often need to be reduced after motor detection to get the motor spin smoothly.

That's assuming you are running FOC. This may be hardware specific though.  So, it may or may not apply to your hardware. Need to experiment with your specific hardware which you didn't mention what it is.

You can read more about it here: https://vesc-project.com/node/943

 

 

NextGen FOC High voltage 144v/34s, 30kw (https://vesc-project.com/node/1477)