X-File: Understanding VESC: the difference between "battery amps" and "motor amps"
The ONLY stable Element = Iron which does not have an EVEN number of atomic particles is:

Iron-57 (31 Neutrons) <-- how does this affect (H) Inductance?!!

But unlike all the others, its "nuclear spin" is considered: "-1/2"

The only others are Iron 54 (28 neutrons), Iron 56 (by far the most common, 30 neutrons), and Iron 58 (32 neutrons)

I think this makes the "spin axis" of the Iron-57 atomic nucleus change continuously through a range of vectors -- ie "precession"

What if this substance was used in a motor?"

,0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/197,2017-01-20 18:24:29 UTC
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So how exactly will the VESC determine the PWM switching frequency in the very first moments of "acceleration" with this theoretical setup?

From Post 59:

devin, post:59, topic:15995 Wrote:It should be somehow possible to determine precisely how the VESC would chop up one second with ON-OFF DC Pulses through any 2 motor phases wires with the hub motor locked in a clamp for 5000w electrical if you know:

Pack Voltage: 50V
Winding Resistance: 0.0415 ohm
Motor Inductivity: "27.13uH"
DC PWM Duty Cycle: %28.8
MAX DC Wattage: 5000w
PWM Frequency: XXXX hz
AVG Pulse On length: 0.XXXXX seconds
AVG Pulse Off length: 0.XXXXX seconds
Battey Amps: 100 A
"Traditional" Amps: 100 A
Motor Amps: 348 A
Motor Amps % ON Time: 28.8%
AVG DC Amps During ON: 348 A
AVG DC Amps During OFF: 0 A

What will the PWM Frequency (Hz) , AVG Pulse On length (sec) & Avg Pulse Off length sec values be?

:confused:

Post 185:

devin, post:185, topic:15995 Wrote:i'm trying to solve for (S) seconds.

In simple terms, how long (Seconds) does it take the current to ramp up to 696 Amps with 27.13uH and 50V?

I found this inductance equation where

V = Volts
H = Inductance
A = Change in Amps
S = Change in Time (Seconds)

V = H x (A / S)

( http://hyperphysics.phy-astr.gsu.edu/hba...nduct.html )

I rearranged the equation to:

S = (A x H) / V

Does "27.13 uH" = "0.00002713 H" ?

If yes, the values are:

V = 50
H = 0.00002713
A = 696
S = X <-- solve for this

When I do the equation I get:

0.00037765 Seconds = (696 A x 0.00002713 H) / 50V

In simple terms I calculate it takes 0.00037765 seconds for the current to ramp up to 696 A @ 50V @ 0.00002713 H @ 0.0415 Ohm

So does S = 0.00037765 seconds?

So why do we want to know how long it takes to get to "696 amps?"

It's because AVG DC Amps During ON: 348 A

This is an average with minimum and maximum values, starting with 0.

The "average amps" of a span of time starting with 0 amps and rising steadily to 696 Amps would be 348 A -- the AVG DC Amps During ON: 348 A value.

I showed that it takes 0.00037765 seconds for the current to rise to 696 A based on the 50 V and 27.13 uH values.

Looking at the % duty cycle value at this time we see it's %28.8

So 0.00037765 seconds is %28.8 percent of some span of time.

This implies the other span of time (OFF) is %100 - %28.8 = %71.2 of the time

If we divide 0.00037765 seconds by %28.8 percent we get:

0.00037765 / 28.8 = 0.00001311 seconds

So 1% of the second is 0.00001311 seconds at this timescale

0.00001311 seconds x 71.2% = 0.00093343 seconds

So:

OFF Time = 0.00093343 seconds (71.2% time)
ON Time = 0.00037765 seconds (28.8% time)

If we add these up we get:

0.00093343 seconds + 0.00037765 seconds = 0.00131108 seconds (100% ON + OFF TIME)

If we want to know how many 0.00131108 second spans of time are in one second we get:

1 second / 0.00131108 seconds spans of time = 762.729 spans in one second

In other words

PWM Frequency = 762.729 Hz
On Time = 0.00037765 seconds
On Time = about 3.77/10,000th's of a second
Off Time = 0.00093343 seconds
Off Time = about 9.33/10,000th's of a  second

So looking at the full spread of variables we end up with:

FULL THROTTLE =

Pack Voltage: 50V
Winding Resistance: 0.0415 ohm
Motor Inductivity: 27.13uH
DC PWM Duty Cycle: %28.8
MAX DC Wattage: 5000w electrical
PWM Frequency: 762.729 hz
On Time = 0.00037765 seconds
On Time = about 3.77/10,000th's of a second
Off Time = 0.00093343 seconds
Off Time = about 9.33/10,000th's of a  second
Battery Amps: 100 A
"Traditional" Amps: 100 A
Motor Amps: 348 A
Motor Amps % ON Time: 28.8%
AVG DC Amps During ON: 348 A
AVG DC Amps During OFF: 0 A
MAX DC Amps During ON: 696 A
MAX Peak Watts During ON: 34,800 watts electrical
Max Amp Limit Settings: 100/348/348 batt/motor/absolute
Full Throttle = 5000w electrical @ all physically possible rpms

In simple terms, a single ON - OFF - ON cycle consists of:

ON 0.00037765 seconds --> OFF 0.00093343 seconds --> ON 0.00037765 seconds

So for @Hummie to get 5000w electrical into his funny looking long wheel in the scenario, he'd actually be reaching momentary 34,800 watts electrical, 762.729 times each second, averaging out to 100 amps DC from his 50V battery... and all of that math happens before the wheel even starts turning!

& that folks, is my Understanding of VESC: Software.

"The Difference Between Battery Amps and Motor Amps"

-Devin

[Image: PMW%20Wave%20Form%20(1)_2.jpg]

",0,2,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/198,2017-01-22 07:29:55 UTC
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Bonus Info:

devin, post:81, topic:16344, full:true Wrote:my theory is ferromagnetism means not only will the force of the electrons in nearby wires be altering the orbits of the electrons around the Iron-56 nucleus (as happens in nearly all elements), but these electron orbits are "coupled" with the spin axis of the Iron-56 atomic nucleus itself... a very rare property amongst all ELEMENTS.

i suspect this is a result of each of the 56 particles in the Iron-56 atomic nucleus posessing the least mass per nuclear particle of all the chemical elements.

since according to E=MC^2, MASS = ENERGY, the "spin" of the Iron-56 nucleus has the least "momentum" per PROTON in it's atomic nucleus.

since electrons are attracted to protons via the fundamental electric force, this results in the spin axis of the nucleus of Iron-56 becoming effectively "coupled" with the "unpaired" electron orbitals below a certain temperature.

Above a certain "temperature," "phonons" destroy this "coupling" effect between the electron orbitals and the Iron-56 atomic nucleus vector of axis of rotation.

So unlike most other elements, when the electrons pass through the nearby wires, this ultimately changes the spin axis of nearby Iron-56 atomic nuclei, not just the electron orbitals themselves.

As a result of this property of "coupling" between the electron orbitals and nuclear spin axis in certain materials like Iron-56, we witness both "spontaneous" "ferromagnetism" and mysterious "(H) inductance" in the world around us.

[Image: upsidedown.jpg]

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/199,2017-01-22 08:25:28 UTC
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A topic was brought up in a related thread which made me think of some new equations which relate to this topic, which I'll repost here for people who will be reading this thread for the 1st time:

devin, post:36, topic:16919 Wrote:This is an illustration of "200 Motor Amps,"

This is an illustration of "200 Motor Amps," a.k.a. AVG Amps During ON, a.k.a. "software defined motor amp limit" which interestingly features PEAK 400A.

[Image: avg-on-amps.jpg]

But instead of 1 second ramp length, typical time lengths would be:

FULL THROTTLE @ STANDSTILL =

On Time = 0.0003083 seconds
Off Time = 0.00099882 seconds

PWM Frequency: 765.04 Hz = 1 Second / (On Time = 0.0003083 seconds + Off Time = 0.00099882 seconds)

On Time = 0.0003083 seconds = (On Time = 0.0003083 seconds + Off Time = 0.00099882 seconds) x (DC PWM Duty Cycle: 23.5795 % / 100)

Off Time: 0.00099882 seconds = ((100 / DC PWM Duty Cycle: 23.5795 %) - 1) x On Time = 0.0003083 seconds

when: Pack V = 35.2V
ohm's law (solve for motor amp limit and ohm winding resistance detection):
200 Motor Amps Limit x 0.0415 ohm = PWM Effective Volts: 8.3V
200 Motor Amps Limit x PWM Effective Volts: 8.3V = 1660W Limit

Battery Amps: 47.15 A = 1660W Limit / Pack Voltage: 35.2V

DC PWM Duty Cycle: 23.5795 % = (PWM Effective Volts: 8.3V  / Pack V: 35.2V) x 100

&

DC PWM Duty Cycle: 23.5795 % = (100 x On Time = 0.0003083 seconds) / (Off Time = 0.00099882 seconds + On Time = 0.0003083 seconds)

1 Second = PWM Frequency: 765.04 Hz x (On Time = 0.0003083 seconds + Off Time = 0.00099882 seconds)

when:
Motor Amp Limit: 200A
Change In Amps: 400A = Motor Amp Limit: 200A x 2

&

35.2 V = Pack Volts
0.00002713 H (27.13 uH) = Inductance
400 A = Change in Amps
S = Change in Time (Seconds) <-- Solve For This

S = (A x H) / V

On Time: 0.0003083 S = (Change In Amps: 400A x H Inductance: 0.00002713) / Pack Voltage: 35.2 V

Also:

V = H x (A / S)

So:

Pack Voltage: 35.2 V = H Inductance: 0.00002713 x (Change in Amps: 400A / On Time: 0.0003083 S)

&

Peak Watts: 14,080w = Change in Amps: 400 A x Pack Voltage: 35.2V

In simple terms, ON time and OFF TIME at full-throttle standstill directly relate with both "VESC-detected motor & battery physical properties H-Inductance, V-Pack Voltage and Ohm-Resistance," and "USER CHOSEN batt/motor/absolute max amp limit settings."

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/202,2017-01-31 19:11:57 UTC
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Hummie, post:203, topic:15995, full:true Wrote:Ok.Even though it's math it can be no-so-straight- forward and you really should just leave the kernel in the center and forget the rest.  And definately don't repeat it.  Don't bother responding to anyone who doesn't get it or disagrees as they'll come round eventually. What the kernel is is that you can completely control the watt output at every rpm and also increase start-up torque and even greatly reduce cogging and decrease noise If they say you're out to lunch wait till dinner and they'll be hungry

@Hummie So Understanding VESC: Software in simplest terms:

[Image: fancy-switch.jpg]

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/204,2017-01-31 22:55:35 UTC
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Ackmaniac, post:205, topic:15995 Wrote:One question. I set my VESC to 10/10/10 for testing and it shuts down every time I give 100% throttle. Why is that? By the calculations it shouldn't be a issue.

@Ackmaniac If you tell me your:

-# of motors <-typically constant
-ohm resistance <-typically constant
-pack voltage <-typically variable
-desired battery watts @ full throttle at all physically possible rpms <-typically constant

then i'll happily calculate the appropriate settings.

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/206,2017-02-01 01:13:57 UTC
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Ackmaniac, post:207, topic:15995 Wrote:I need the reason why the VESC shuts down with those settings.

@Ackmaniac Impossible to calculate without the requested info.

-# of motors <-typically constant
-ohm resistance <-typically constant
-pack voltage <-typically variable
-desired battery watts @ full throttle at all physically possible rpms <-typically constant

",0,1,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/208,2017-02-01 01:44:29 UTC
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Ackmaniac, post:209, topic:15995, full:true Wrote:Do the math for hummies single motor with those settings and tell me why it shuts down.

@Ackmaniac That's unrelated to the first question you asked.

Ackmaniac, post:205, topic:15995 Wrote:I set my VESC to 10/10/10 for testing and it shuts down every time I give 100% throttle. Why is that?

I've already posted the info for @Hummie's motor.

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/210,2017-02-01 01:46:54 UTC
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Ackmaniac, post:211, topic:15995, full:true Wrote:But why does my vesc shut down with these settings?

@Ackmaniac with the requested info, I can provide you an answer.

",0,2,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/212,2017-02-01 01:50:26 UTC
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Ackmaniac, post:213, topic:15995, full:true Wrote:1 motor
0.016 resistance
360 watts
10S liion
Even acceleration.

@Ackmaniac so we have 1 motor and 1 VESC
pack voltage: 38V nominal = 10S x 3.8V nominal per cell
ohm resistance: 0.016 ohm
battery watt limit: 360 W

go to an ohm's law calculator and enter:

360 W & 0.016 ohm

this gives 4 values:

2.4 V <-- effective PWM voltage @ full throttle @ standstill
150 A <-- this should be your "Motor / Absolute" amp limit settings"
360 W
0.016 ohm

9.47 A = battery watt limit: 360 W / pack voltage: 38V nominal

9.47 A <-- this should be your "Battery" amp limit setting

this gives:

10/150/150 batt/motor/absolute max amp limit settings

this gives:

Duty Cycle 6.31% @ Full Throttle @ Standstill = (Effective PWM voltage @ full throttle @ standstill: 2.4 V / Pack Voltage: 38 V) x 100

this gives:

FULL THROTTLE = 360 W Electrical @ all physically possible rpms

@Ackmaniac In simplest terms your settings need to be 10/150/150 batt/motor/absolute.

"Motor heating" averaged throughout motor will be equivalent to maximum 10 "battery amps".

",0,1,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/214,2017-02-01 02:05:39 UTC
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