Motor Current Limiting: More Power and Less Heat!!!

[eP]

It is unable to burn the motor in 3-5 seconds for the sake of heat. Cripled controller will stay much longer in that area.

You still don't understand....

The "Motor Current Limited" bike is unable to produce heat in large amounts anywhere in it's powerband. The "Motor Current Limited" bike will never overheat... it's restricted from being able to do that.

It takes 2.59 seconds for the "Motor Current Limited" bike to get to 10 mph after which point things are always "ideal". The "Battery Current Limited" bike takes 1.84 seconds to get to 10 mph. The difference is only 0.75 second... that's "three quarters of a second" difference.
[/i]

It is at flat. Tell us Mr Teacher how many seconds your cripled "blind" controller need to catch up at speed the normal one ?

At higher gears the acceleration is lower and lower so it must take many seconds of extreme continuous heating to take back that 0.75 second losed at low rpms.

At what speed cripled one is able to catch up the normal one ?

After that "three quarters of a second" things only improve and remain positive for the "Motor Current Limited" bike.

..."three quarters of a second"

How many seconds cripled one is late at 15% grade slope ?
How many seconds its need to reach the same speed which has normal one at the same moment ?
( It is the time until normal bike will be faster then cripled one )

ps.
Mr Teacher leave all bullshits for yourself. We need real calculations - we aren't as dumb as you want.

 

[safe]

The "Motor Current Limited" bike is unable to produce heat in large amounts.

Show us some efficiency figures to back up that statement.

Well, I've done a lot already today, so I'm going to recycle a chart that I've already produced before. This chart compared power and torque. Torque is directly related to current and current is what creates heat. So you can look at the charts and see that the two types have similiar "middle range" torque and heat. On "average" the two will produce about the same heat. In "real world" riding since the "Motor Current Limited" bike gives good feedback and is heat restricted because of current limiting at low rpms it really doesn't have any choice and can't overheat. The "Battery Current Limited" bike gives poor feedback to the rider and (I know in my own experience) that you can run any of three gears and it feels about the same. That's what you call a "bad situation" when you can run in a wrong gear and have no "feedback" to tell you it is a "bad gear". There are discussions about lights and meters and even (joke) "electrodes" to "jolt" the rider and force him to shift at the right moments, but the "Motor Current Limited" bike gives plenty of feeback by simply "removing" power where you should never be.

So look at the charts and try to soak it up...

This theory has so far been "approved" by Lowell and Fechter. It would be great when everyone understands and says:

"Yeah, you're right, that is a cool idea." 8) (joke... a cool motor idea)

One day maybe...

 

[safe]

At what speed "motor current limited" one is able to catch up the "battery current limited" one ?

That's also been proven before with this chart...

 

[TylerDurden]

Well, I've done a lot already today, so I'm going to recycle a chart that I've already produced before.

Save the spreadsheet masturbations for your bathroom and produce some numbers.

Your useless spreadsheets are not proof. Proof is when others can replicate your work and show it is viable.


Neither Fechter nor Lowell have vetted the concept. Fechter has said he understands the shift in the powerband by raising the current limit; not the viability of the concept.

You must be tired so go take a nap.

 

[eP]

The "Motor Current Limited" bike is unable to produce heat in large amounts.

Show us some efficiency figures to back up that statement.

Well, I've done a lot already today, so I'm going to recycle a chart that I've already produced before. This chart compared power and torque. Torque is directly related to current and current is what creates heat. So you can look at the charts and see that the two types have similiar "middle range" torque and heat. On "average" the two will produce about the same heat. In "real world" riding since the "Motor Current Limited" bike gives good feedback and is heat restricted because of current limiting at low rpms it really doesn't have any choice and can't overheat.

The heat is restricted by 1.84 seconds after that the heat is rising to 156% of heat generated by more restricted normal controller.

So overheating is quite possible as your controller is "blind" and suck more !!

The "Battery Current Limited" bike gives poor feedback to the rider and (I know in my own experience) that you can run any of three gears and it feels about the same. That's what you call a "bad situation" when you can run in a wrong gear and have no "feedback" to tell you it is a "bad gear". There are discussions about lights and meters and even (joke) "electrodes" to "jolt" the rider and force him to shift at the right moments, but the "Motor Current Limited" bike give plenty of feeback by simply "removing" power where you should never be.

Removing the power at start so even at flat you lose 0.75 seconds at few meters distance.

At Formula_1 0.75 seconds is a huge lost at one leap - few kilometers.
You lose it in less then 3 seconds at flat in spite of 25% bigger power budget.

So look at the charts and try to soak it up...

This theory has so far been "approved" by Lowell and Fechter. It would be great when everyone understands and says:

"Yeah, you're right, that is a cool idea." 8) (joke... a cool motor idea)

One day maybe...

Don't escape Mr Teacher - questions too hard ? :wink:

 

[safe]

Your useless spreadsheets are not proof. Proof is when others can replicate your work and show it is viable.

Okay, I can appreciate that.... you want to "do the work" yourself and validate my thesis. That's very much the way the "Scientific Method" works. That's great!!!

But at this point... in order to have results that are produced in an "impartial" way you would need to create all the motor data yourself and simulate the two controllers and then make your own evaluations.

I can lead you to the "water" but if you want "proof" you need to "drink" the "water" yourself.

The "theory" is simple enough... by limiting the current on the motor side while at the same time raising the limit overall you get a "different" powerband that works better for a geared bike.

You have the "theory"... now you have to "put up or shut up" and provide the intellectual "muscle" to do the work:

Are you up for the challenge?

Are you willing to devote the time to create your own simulations and work through all the formulas yourself?

I've been allowing people an "easy" route to knowledge, but you are 100% right... to be SURE of this theory you need to do the math yourself...

 

[safe]

The heat is restricted by 1.84 seconds after that the heat is rising to 156% of heat generated by more restricted normal controller.

The "Motor Current Limited" bike creates 26,673 watts of heat to get to 10 mph.

The "Battery Current Limited" bike creates 55,264 watts of heat to get to 10 mph.

So the "Motor Current Limited" creates 50% LESS heat to get to 10 mph...

This only makes "sense" because the "Motor Current Limited" bike uses less torque and accelerates slower for those first 2.59 seconds... it's kind of obvious that this would be so...

 

[TylerDurden]

You bear the burden of proving your theory, not anybody else.

Truth is, you are to unable show your math.

 

[safe]

Truth is, you are to unable show your math.

Lowell joked that I'm behaving like I have the "patience of a school teacher". Okay... if you want your "hand held" through the process we can do that. eP seems to want to take a "class" on this too and I'll be your "teacher" and walk you through the process.

Let's assume that this is going to take "days" to complete. The Indy 500 is just starting (prelude anyway) and I want to watch that, but start thinking up questions and we can walk through it from the beginning to the end.

This can be our "engine theory class" thread...

Your homework...

Think about the motors they use at the Indy 500. What kind of powerband do they have?

 

[TylerDurden]

Let's assume that this is going to take "days" to complete.

See... you have no math to show.

If it takes you a few days, that's fine. We can wait.


Your homework: none. You are finished. You have no proof.

 

[eP]

The heat is restricted by 1.84 seconds after that the heat is rising to 156% of heat generated by more restricted normal controller.

The "Motor Current Limited" bike creates 26,673 watts of heat to get to 10 mph.

The "Battery Current Limited" bike creates 55,264 watts of heat to get to 10 mph.

So the "Motor Current Limited" creates 50% LESS heat to get to 10 mph...

This only makes "sense" because the "Motor Current Limited" bike uses less torque and accelerates slower for those first 2.59 seconds... it's kind of obvious that this would be so...

Heat is measured in Joules Mr Teacher :lol:

In Watts we measure the Power

Never mind first 3 seconds of heat - what is the next Mr Teacher ?

What is at moderate slope ?

I see the riders adrenaline level at yours cripled bike which is unable to accelerate at the similar level then more power efficient lower power normal bike.
8)

 

[Drunkskunk]

I feel the need to feed some trolls.


Joules = watts x seconds, therefore watts = joules/seconds.
A 1000 watt fire will dissipate 1000 joules per second.

But if that don't float yer boat, how about:
1 watt = 3.41 BTU
or:
1 calorie = 4.2 joules
or:
1 btu = 0.252164401 kilocalories

 

[TylerDurden]

I feel the need to feed some trolls.

Welcome...

Perhaps we can chow on this:

If the heat is 50% less, is the torque at the motor 50% less?

If the torque at the motor is 50% less, will the gear reduction need to be double to achieve the same torque at the hub?

If the gear reduction is double, will it take twice as long to reach 10mph?

How many total watts are wasted in heat by that time?

Anybody... anybody???

 

[eP]

Cripled controller suck between 12A (at start) and 50A (when reach max rpm ).
So bottom estimation of sucked average current is (12+50)/2=31A
31 A * 2.59 s = 80.29 C
for the heat goes all time the same circa 12A (at battery side = 50A at the motor side), so for the heat goes 12*2.59 = 31.08 C

Normal controller draw all time the same 40A, so to reach 10mph speed its need 40 * 1.84 = 73.60 C
for the heat goes between 40A and 8A (20% battery current at max efficiency rpm ), so the upper estimation of average cuurent which goes for heat is 24A. So at 1.84 s 24*1.84 = 44.16 C goes for heat.

So we see the normal bike need less Coulombs (or Joules) to reach 10 mph speed than cripled one in spite of more Coulombs goes for heat.

As we can see saving are very small and quite virtual as in next seconds cripled motor/controller will waste much more energy than normal one.
As a result savings at the moment when the speed will be equal for both will be next to nothing at cripled performance.

At moderate slope the virtual savings could change to real loss, at much more cripled acceleration of course.

At extremly high slope is possible that cripled bike will be unable to move away, so will generate only the loss.

 

[fechter]

The "Motor Current Limited" bike creates 26,673 watts of heat to get to 10 mph.

The "Battery Current Limited" bike creates 55,264 watts of heat to get to 10 mph.

So the "Motor Current Limited" creates 50% LESS heat to get to 10 mph...

Now something is violating my common sense alarm.

55,264watts of power would turn your motor into a flaming rocket motor.
did you mean Watt-seconds?

Secondly, in order to know how much heat is generated, it is necessary to know the motor efficiency at all operating points.

 

[eP]

The "Motor Current Limited" bike creates 26,673 watts of heat to get to 10 mph.

The "Battery Current Limited" bike creates 55,264 watts of heat to get to 10 mph.

So the "Motor Current Limited" creates 50% LESS heat to get to 10 mph...

Now something is violating my common sense alarm.

55,264watts of power would turn your motor into a flaming rocket motor.
did you mean Watt-seconds?

Secondly, in order to know how much heat is generated, it is necessary to know the motor efficiency at all operating points.

Our Teacher is tired i suppose. And he fully trust in all his numbers, never mind the units.

 

[safe]

Now something is violating my common sense alarm.

55,264watts of power would turn your motor into a flaming rocket motor.
did you mean Watt-seconds?

I hope everyone managed to watch the Indy 500... it ended it up really, really long with the rain delay, but it was a good race.

Anyway...

That was just a quick summation of watts of heat over the span of time that the bike accelerated. It took 48 intervals and so the actual "average heat" over that period would be:

The "Motor Current Limited" bike creates an average of 556 watts of heat as it gets to 10 mph in 2.59 seconds.

The "Battery Current Limited" bike creates an average of 1151 watts of heat as it gets to 10 mph in 1.84 seconds.

To really get accurate you would convert to Joules which are watts per second. That might be interesting to try converting... but you get the general idea already I suspect. (we can go further if need be)

Moving on...

Is there general agreement that we need a "Motor Class"?

I've been putting together a "study guide" and I think it will turn out pretty good in the end.

This will take some time...

 

[xyster]

Is there general agreement that we need a "Motor Class"?

Albeit self-directed, that's what this forum is.

Duck, Teach! Incoming spitwad!

 

[eP]

The "Motor Current Limited" bike creates an average of 556 watts of heat as it gets to 10 mph in 2.59 seconds.

The "Battery Current Limited" bike creates an average of 1151 watts of heat as it gets to 10 mph in 1.84 seconds.

To really get accurate you would convert to Joules which are watts per second. That might be interesting to try converting... but you get the general idea already I suspect. (we can go further if need be)

So lets go further and calculate how many watts of heat will generate "Battery Current Limited" at higher gears until yours reach the same speed at the same moment.

And lets go even further and repeat all the calcs for the 10% slope.

 

[safe]

So lets go further and calculate how many watts of heat will generate "Battery Current Limited" at higher gears until yours reach the same speed at the same moment.

And lets go event further and repeat all the calcs for the 10% slope.

We will get to all your questions in time... but first we are going to have to build a "foundation" upon which we all agree. For that we need a class and study guides and worksheets to do our work.

This is coming very soon... 8)

 

[safe]

Conversion Needed!

Before I get started on a new "Motor Class" thread I want to get my study guides and worksheets converted to regular "excel" (.xls) format from the "works" (.wks) format I'm using.

Could someone convert these for me?

 

[eP]

So lets go further and calculate how many watts of heat will generate "Battery Current Limited" at higher gears until yours reach the same speed at the same moment.

And lets go event further and repeat all the calcs for the 10% slope.

We will get to all your questions in time... but first we are going to have to build a "foundation" upon which we all agree. For that we need a class and study guides and worksheets to do our work.

This is coming very soon... 8)

I would like remind you: we are at page number 20 now.
And you have no enough "foundation" to calculate even one case ??
I hope you will be able to do that very soon ...

Good luck 8)

 

[safe]

And you have no enough "foundation" to calculate even one case ??
I hope you will be able to do that very soon ...

The "advanced" students (like Fechter and Lowell) already "got it" a long time ago.

But (some of) you guys need a little "special education" assistance and so I'm going to truly start from the very beginning and go all the way through to the end. This way an "absolute beginner" (who might want to learn) could follow along from beginning to end and know all they need to know about electric motors.

I'm trying to once and for all educate people about motors...

I wish someone could have done such a favor for me rather than have to learn it all myself the "hard way" by research over many internet sites. This will in one place cover all aspects of electric vehicle motor powerbands, heat, efficiency, etc...

99% of the people who "think" they know how to model motors don't get past the "wicked quadratic equation" that is mandatory to solve the standard controller equation. So this will be a good class... 8)

I plan to start a new thread...

 

[TylerDurden]

The "advanced" students (like Fechter and Lowell) already "got it" a long time ago.

Actually, they have declined to agree that your theory has any merit, by not answering the questions above.

If you are so sure they feel you are 100% correct, Why don't you ask them to say so here and now?

In fact, not one person has gone on record to say your theory is even worth wiping their ass with.

Too bad you cannot offer any proof of your own. EP even showed you how, and you still don't get it.

Put up or shut up.

 

[TylerDurden]

Could someone convert these for me?

Done.