Search found 255 matches

by devin
07 May 2018, 15:12
Forum: General
Topic: throttle range/travel on 2.4 ghz mini remote
Replies: 2
Views: 311

Re: throttle range/travel on 2.4 ghz mini remote

this is a theory: look at this chart representing a board with 50a battery limit & 120a motor amp limit settings. i assume that the throttle range in your setup controls the motor current... so at 0mph, if you look at the blue line top left chart (motor amps), 100% throttle corresponds with 120a...
by devin
22 Apr 2018, 16:27
Forum: General
Topic: "Peak Efficiency" Control Mode?
Replies: 110
Views: 18209

Re: "Peak Efficiency" Control Mode?

Here's a new comparison between the "classical algorithm" (bldc current control) and hypothetical "efficiency control" @ 100% throttle... notice both boards are capable of 85mph (bottom left chart)... this chart assumes the vesc hardware is modded to allow 300a motor amps, 300a b...
by devin
24 Mar 2018, 09:46
Forum: General
Topic: would this method be accurate to determine a motor winding resistance?
Replies: 3
Views: 548

Re: would this method be accurate to determine a motor winding resistance?

Is this accurate? In the sense of "is this theoretically correct" the answer is: Yes. (albeit that your result includes the resistance of the VESC and maybe also the battery wires). In the sense of: will the result be the same (similar) in different cases? The answer is: no. i believe Mr....
by devin
24 Mar 2018, 09:36
Forum: General
Topic: General questions
Replies: 12
Views: 1889

Re: General questions

Suppose the rider is coasting at 10mph (below no load speed) at 0% throttle...

while coasting at 0% throttle, is the vesc applying a pwm effective voltage which is equal to the back emf voltage at all times or are all the mosfets “off”?
by devin
22 Mar 2018, 16:46
Forum: General
Topic: General questions
Replies: 12
Views: 1889

Re: General questions

my understanding is the back emf voltage at this speed will exceed the battery voltage.\ When the voltage from the motor exceeds the battery voltage, the parasitic diodes in the mosfets will function as a three-phase-rectifier. Thus even without using the throttle, the motor will start working as a...
by devin
13 Mar 2018, 13:03
Forum: General
Topic: Low speed high torque
Replies: 3
Views: 808

Re: Low speed high torque

because many folks have been confused previously about the difference between battery amps and motor amps-- to illustrate, here are 2 charts I made for comparing the theoretical performance of 50a battery amps vs 50a motor amps: *please make sure you do not exceed the amp limits of any of the hardwa...
by devin
13 Mar 2018, 12:26
Forum: General
Topic: Low speed high torque
Replies: 3
Views: 808

Re: Low speed high torque

have you tried increasing the motor amp limit as torque is directly proportional to motor amps. if you double the motor amp limit you double the torque limit. a friend of mine solved his low speed torque startup issues by using the (some would say extreme method) of boosting the motor amp limit (in ...
by devin
11 Mar 2018, 16:24
Forum: General
Topic: General questions
Replies: 12
Views: 1889

Re: General questions

Dor, please ignore Devin. He's got some non-scientific ways to get some results that are not scientifically valid. He starts out with assuming a gear ratio. That's the last thing you need. The motor can put out 2500 Watts. If we take that to be correct, the main question is: Can you do 15mph on 250...
by devin
11 Mar 2018, 15:01
Forum: General
Topic: would this method be accurate to determine a motor winding resistance?
Replies: 3
Views: 548

Re: would this method be accurate to determine a motor winding resistance?

Second Example: This is a still frame from Benjamin Vedder's electric skateboard logging video: http://tppsf.com/27a-41w-1.jpg Speed (mph): 0mph Battery Amps: 1.26a Motor Amps: 27.33a <---------- Battery Voltage: 33.2v Back EMF Voltage: 0v <---------- Electrical Watts: 41.8w <---------- Since Back E...
by devin
11 Mar 2018, 14:48
Forum: General
Topic: would this method be accurate to determine a motor winding resistance?
Replies: 3
Views: 548

would this method be accurate to determine a motor winding resistance?

Hello, Does anybody know if this method for determining a motor's winding resistance from data logging videos will give accurate results? Thanks, Devin ---------- Example 1: http://tppsf.com/accelleration-1.jpg From this screenshot of a data log I want to determine the resistance in ohms from lead t...

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