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FOC for BDC?

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SlimSh8y
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FOC for BDC?

Hey everybody. I am very new to the whole VESC thing and I have a couple questions about programming with the VESC Tool. The only tutorial I can find is here on VESC-Project but when I go through the Motor Configuration Wizard section of the tutorial, it says that under the "Choose Motor Type" section that there are three options; BLDC, FOC, and DC and that I should select FOC. However, I have a Brushed DC motor. Do the FOC settings even work on a BDC motor? Am I supposed to select FOC even though I have brushed motor for the VESC Tool software to be able to "read" and "spin up" the motor? Canl I damage the VESC or the motor if I were to select FOC when programming the VESC for a brushed motor? Any advice is greatly appreciated. Thank you..

 
frank
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If you have a brushed DC motor you need to select DC. Only the two outer motor cables are connected (A and C).

Frank

SlimSh8y
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@frank yes I know that, but there are no motor detection settings under DC. My motor does not show up in the throttle curve under additional info and nothing shows up under Duty or Current. I'm having problems with torque and speed with my setup.. When I had a regular esc connected to this motor on my esk8 I could start without pushing the board even on an incline, and was getting approx 25mph. Now with the VESC I have to push to get started and it's only going approx 5-10mph. There are zero tutorials and very little info available for running a brushed motor with the VESC. I have entered the parameters of my motor from it's nameplate and for my battery but as I said, there are no motor detection settings available to me under DC and I don't know what to do to fix performance?

 
 
 
frank
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Please have a look at the left hand side menu. Motor settings>> General and DC.

Frank

SlimSh8y
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@frank yes I am aware of where the settings are in the tool. As I said before, I entered the parameters of my battery and for my motor from its nameplate but I am having major performance issues with these parameters in the settings and I don't know what to do to fix them. When I had same motor and battery on different ESC I could start my board without pushing it, even on an incline and rolling backward and I was getting about 25mph. Now, with the VESC which is supposed to be so great, I have to push my board to start it and I'm only getting approx 10mph. There is no "motor detection" feature in 'DC' or in 'General' and I don't know how to "tweak" the settings to get the performance I know this motor is capable of and I'm worried about possibly ruining it or the VESC by guessing at the settings which is also a royal pain in the ass itself because with no load on the board it spins up to 100" with very little pressure on the remote trigger and gives no indication of torque so I have to take my electronics' cover off, connect VESC to computer, open the VESC Tool, change whichever of the settings, disconnect from computer and replace cover, take board outside, get on it and see what happens every single time I need to change anything. Very inconvenient and time-consuming. Can't anyone here help me with settings for a brushed dc motor? Or tell me who I could get help from? Or tell me where I can find any kind of tutorial or instructions for brushed motor settings? I mean come on, isn't this the forum created by the guy who designed this thing? Isn't this where the whole thing started and where all the experts are supposed to be? Yet nobody here at all can help me with this???

TechAUmNu
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Brushed dc motors of a similar size tend to be significantly less powerful. If you were running with a normal brushed esc before they do not have current limiting, so they will just dump whatever current into the motor that it can. Which normally ends in the motor or controller being destroyed at some point. If you want to get similar starting performance on the VESC you would need to increase the motor current to get high torque startups. Then you use the battery current limit or power limit settings to limit the power going into the motor to a sensible amount when it is moving. As for high speed I am not sure why it doesn't reach the same top speed, if you are actually at full throttle and only getting 10mph you are probably torque limited. Can you give us any details about your setup, motor specs, battery, etc?

The Additional Info tab is more for keeping track of your setup, doesn't change anything.

SlimSh8y
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Sure @frank. My setup is as follows; 4.12HW Vedder's genuine BOM VESC on 3.68FW, 36v 600w 3600 rpm brushed dc motor rated at 1.5 torque, 78% efficiency, & 32.5A continuous with 4 brushes (poles) / 2 magnet pairs, 150mm wheels, 16t motor pulley & 36t drive pulley, a 10s6p Li-ion (18650's) 13.2Ah 60A continuous battery, and a PPM RC remote and receiver.. The esk8 calculator says this setup should be getting 28mph no load and 22mph loaded. I previously ran this setup with a cheap chinese ebike 36v 800w speed controller for many months with no ill effects on motor or controller and was getting approx 20-25mph and could start my board w/o pushing even on an incline rolling backward. I switched to the VESC because everyone I talked to said they were much better and I wanted brakes, reverse, and wireless throttle control. Have had nothing but headaches ever since as there are zero tutorials or instructions available for running DC mode with the VESC and no motor detection feature available in DC mode. I have since actually tried to have VESC Tool detect my motor in FOC mode and the first settings would register and turn green but the second settings where it supposed to spin up the motor it would just cog out and stay red. I also have a couple additional questions: In the VESC Tool on the bottom left side there are boxes with values in them, mine are: D 0.20, w 5000 RPM, IB 3.00 A, I 3.00 A, P 0.00, HB 3.00 A. I know these values are; D = Duty Cycle, I = Amps, IB = Brake Amps, HB = Handbrake Amps, the P value is Position but mine is 0.00 and what does that mean? The w 5000 RPM value is Speed but is that Max RPM's or the speed at the I value? And I did not enter these values so where do they come from? Thank you very much for your time.

 
TechAUmNu
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The reason there is no real info on DC mode is simply that I don't think anyone really uses it. 

DC motors are very simple to control, you just apply a voltage and then limit the current to keep it below your set limit.

Make sure you have the correct current settings in the Motor Settings->General->Current page, those are going to be the settings that change how much torque the motor will produce. What I think you will find for DC motors is that if your current limit is low then when you get to a higher speed the motor will draw more and more current until you reach a point where the current limit limits your speed. 10mph sounds very slow so that really doesn't seem right.

Those settings on the bottom left are for bench testing your motor using VESC tool. When you enable keyboard control with the button on the right side bar, you can use the left and right arrows to run the motor in current mode with the current limited to the setting in the "I" box. Up and down arrows will run in duty cycle mode using the "D" field, current will be limited to the max current setting.

Could you save your motor configuration and upload it so I can take a look?

SlimSh8y
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How do I do that?

 
TechAUmNu
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"File->Save Motor Configuration XML as..."

Then upload the file to google drive or drop box or something.

 

frank
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As TechAUmNu sated, the cheap DC motor controllers you can buy are voltage controlled only, just like any random RC-Motor controller out there.  The Amp flow is not monitored and if you overstress the system the controllers will just go up in flames or your fuse blows (if you have one installed).The logic stage of such controllers is smart like a potatoe. The VESC will monitor, control and  limit your current flow. Probably you have to allow more current to flow (within the safe region of what your ESC can handle).

About 34A continuous is what a HW4.12 ESC can handle if the PCB sees some airflow. Settings can be higher (eg 50A) if you don't push the throttle down all the time. but your motor needs to be able to cope with the currents, otherwise it will get hot and the heat potentially fries the motor.