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  #41  
Old 12-19-2018, 09:53 AM
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Originally Posted by Functional Artist View Post
I use these Amp/Volt meters.
They can handle up to 300VDC & 500A

https://www.ebay.com/itm/DC-300V-500...item19f02e600f
Do you think there would be any value in getting the KWH gauge too?
  #42  
Old 12-20-2018, 07:53 AM
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GPS'd her at 24mph yesterday set to 75% power and the controller in "Balanced Mode". Which would be around 35-37volts 5165rpms +/- depending on the battery charge. BMI calc puts that at 28mph so a little disappointed and am going to pick up a 12T and 15T sprocket to try.
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Old 12-20-2018, 11:50 AM
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GPS'd her at 24mph yesterday set to 75% power and the controller in "Balanced Mode". Which would be around 35-37volts 5165rpms +/- depending on the battery charge. BMI calc puts that at 28mph so a little disappointed and am going to pick up a 12T and 15T sprocket to try.
Hmmmm

Did you try-n-run your numbers thru the "ball Park Equation"?

MS/GR=ASxTC=IM/FT=FMxHR=FHxMM= MPH

Motor Speed/Gear Ratio=Axle Speed x Tire Circumference = Inches per Minute traveled/Foot(12) = Feet per Minute traveled x Hour(60) = Feet per Hour traveled x MPH Multiplier(.000189) = Miles Per Hour

http://www.diygokarts.com/vb/showthread.php?t=38785

---------- Post added at 01:50 PM ---------- Previous post was at 01:30 PM ----------

Quote:
Originally Posted by Quinc View Post
Do you think there would be any value in getting the KWH gauge too?
I have not used one, yet

...but, I just picked up one of these: (~$12.00)
(to monitor the 60VDC system/2,000W Boma, that's goin' in the Atom kart)

https://www.ebay.com/itm/Digital-DC-...53.m2749.l2649

Digital DC 6.5-100V 100A DC Voltmeter Ammeter Volt Amp Power Energy Meter

Function
1. electrical parameter measurement function (voltage, current, power, energy).
2. The voltage alarm function (over voltage alarm thresholds, backlighting and voltage flicker tips).
3. The power button clear function.
4. Power-down data storage function.
5. Large-screen LCD screen full display function (display voltage, current, power, energy).
6 backlight

Display Format
1. Power: measurement range 0 ~ 10kW
1kW display format within 0.0 ~ 999.9W;
From 1kW display format 1000 ~ 9999W.
2. Power: measurement range 0 ~ 9999kWh
10kWh within the display format 0 ~ 9999Wh;
Above 10kWh display format 10 ~ 9999kWh;
3. Voltage: test range 6.5 ~ 100V
Display Format 6.50 ~ 99.99V
4. Current: Test Range 0 ~ 100A
Display Format 0.00 to 99.99.

Specifications
Working voltage: 6.5 ~ 100VDC
Test voltage: 6.5 ~ 100VDC
Rated power: 100A / 10000W
Measurement accuracy: 1.0

* This unit may not work in your situation (it'll only work on systems of up to 100VDC & 100A)
...are you sure you'll need to monitor up to 400A?
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  #44  
Old 12-20-2018, 02:32 PM
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Originally Posted by Functional Artist View Post
Hmmmm

Did you try-n-run your numbers thru the "ball Park Equation"?

MS/GR=ASxTC=IM/FT=FMxHR=FHxMM= MPH

Motor Speed/Gear Ratio=Axle Speed x Tire Circumference = Inches per Minute traveled/Foot(12) = Feet per Minute traveled x Hour(60) = Feet per Hour traveled x MPH Multiplier(.000189) = Miles Per Hour

http://www.diygokarts.com/vb/showthread.php?t=38785[COLOR="Silver"]

...are you sure you'll need to monitor up to 400A?
On this motor I doubt I am anywhere near 400 and I think the most anyone has measured out of the kelly 400a controllers is just over 300.. But when I put on my imperial 3.6hp 36v motor I might be able to max her out.

What part of the equation do I put in my fat arse? Should probably figure out what the max tire pressure I can get away with too.
  #45  
Old 12-20-2018, 05:50 PM
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Correct me where I'm wrong but double power will take double something else (volts?) so the 36v 3.6hp motor at 72v would be 7.2hp? And then that's around 5500 watts and just under 80amps. Is that totally flawed math and logic?

---------- Post added at 07:50 PM ---------- Previous post was at 07:43 PM ----------

Oh, rated/constant hp vs peak hp is probably what I'm missing. 7.2 might be rated and you might pull more like 20 peak for X seconds (300lb friend up a hill), which then would make your 400a more likely. Is that right?
  #46  
Old 12-21-2018, 12:54 AM
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Originally Posted by sikbrik View Post
Correct me where I'm wrong but double power will take double something else (volts?) so the 36v 3.6hp motor at 72v would be 7.2hp? And then that's around 5500 watts and just under 80amps. Is that totally flawed math and logic?

---------- Post added at 07:50 PM ---------- Previous post was at 07:43 PM ----------

Oh, rated/constant hp vs peak hp is probably what I'm missing. 7.2 might be rated and you might pull more like 20 peak for X seconds (300lb friend up a hill), which then would make your 400a more likely. Is that right?
The more I read about phase to phase and different ways of measuring motors I get more and more confused. So far I have just learned that a 20lb 1000w motor will make a **** of a lot more torque then a 10lb 1000w motor. I need to get my amp gauge hooked up so I can make more since of it all.

Imperial 36v motor has 100a stamped on the side. So it is going to be a lot. Even going from my 200a controller to the 400a kelly was a significant difference on the leeson 1hp I am running now.

  #47  
Old 12-22-2018, 12:08 AM
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Trail was a lot bumpier with tree roots then I was expecting.
https://youtu.be/sDAMkK42UAI
  #48  
Old 12-22-2018, 08:02 AM
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Nice job!

It seems to move right along

I like the video footage from the 2nd person point of view.

Top speed?
Amp draw? (max & const.)
How long does the batt pack last? (distance or time)
Anything get hot? (motor, controller, batt pack or cables/wires)
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  #49  
Old 12-22-2018, 08:27 AM
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Looks like fun! Same questions as FA
  #50  
Old 12-22-2018, 10:14 AM
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Originally Posted by Functional Artist View Post
Nice job!

It seems to move right along

I like the video footage from the 2nd person point of view.

Top speed?
Amp draw? (max & const.)
How long does the batt pack last? (distance or time)
Anything get hot? (motor, controller, batt pack or cables/wires)
Top speed @ 75% was 24mph
Amp draw = I am too cheap to buy the lcd gauge
Batt pack = That ride was around 14minutes and the packs charged 7800mah and dropped from 4.2v to 3.9v. I have the kelly set to stop when they get to 3.65v
Heat = when I got home the motor was a little warm to the touch, batteries and controller where cold (it is 50 degrees outside)

Going to run her at the full 100% 7500rpms today and find the top speed and see how the motor does.
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Old 12-22-2018, 02:27 PM
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Set the kelly to 100% and "speed" Setting. But only saw 25mph. Wondering if there is some kind of governor on the Leeson motor or something I am missing in the kelly settings.
  #52  
Old 12-23-2018, 05:44 PM
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From what I've read, and that means there's not an ounce of known fact in what I'm saying, there's a limit to how many cycles the controller can "pulse" which basically self-limits the rpm of the PM motors, based on its design. There's a formula out there to figure this out but it has something to do with the number of phases and poles. I wonder if that's what you're bumping up against?

Maybe as an interim, you could do what you said and just gear it down to take advantage of the tons of torque?
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  #53  
Old 12-23-2018, 07:04 PM
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Quote:
Originally Posted by Quinc View Post
Set the kelly to 100% and "speed" Setting. But only saw 25mph. Wondering if there is some kind of governor on the Leeson motor or something I am missing in the kelly settings.
I am still trying to learn the intricate details of these electric motors
...but, thinkin' about it
Do you remember the conversations we had a while back?

http://www.diygokarts.com/vb/showthread.php?t=39287

...where Sid said "since what the motor COULD draw is exactly the amount the motor WILL draw if it needs to."

...& I also remember him telling me/us (one time or another) that a motor is simply a power convertor.
(it turns electrical energy into mechanical/rotational energy)
...kinda like a light bulb converts electrical energy into luminous/light energy

What I'm gettin' at & if I'm understanding this correctly, is
...it's the size of the convertor (motor) that matters.

Think about it this way:
If a 60W light bulb connected to a 110V power supply will emit X amount of light
& a 75W bulb connected to the same voltage power supply will emit Y amount of light
& then, a 100W bulb also with the same voltage power supply will emit Z amount of light.
(each convertor happily drawing exactly what it needs)

You see, (again, if I'm understanding this correctly)
...a larger convertor (motor or light bulb) will produce more...rotational or light energy, from the same power supply.

Does this make sense?
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  #54  
Old 12-24-2018, 09:57 AM
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Quote:
Originally Posted by Functional Artist View Post
I am still trying to learn the intricate details of these electric motors
...but, thinkin' about it
Do you remember the conversations we had a while back?

http://www.diygokarts.com/vb/showthread.php?t=39287

...where Sid said "since what the motor COULD draw is exactly the amount the motor WILL draw if it needs to."

...& I also remember him telling me/us (one time or another) that a motor is simply a power convertor.
(it turns electrical energy into mechanical/rotational energy)
...kinda like a light bulb converts electrical energy into luminous/light energy

What I'm gettin' at & if I'm understanding this correctly, is
...it's the size of the convertor (motor) that matters.

Think about it this way:
If a 60W light bulb connected to a 110V power supply will emit X amount of light
& a 75W bulb connected to the same voltage power supply will emit Y amount of light
& then, a 100W bulb also with the same voltage power supply will emit Z amount of light.
(each convertor happily drawing exactly what it needs)

You see, (again, if I'm understanding this correctly)
...a larger convertor (motor or light bulb) will produce more...rotational or light energy, from the same power supply.

Does this make sense?
This is the most powerful motor I have ran so far and it "should" be able to handle anything I can throw at it.

After researching and playing with the speed calculators it looks like it has a centrifugal governor set to 5k rpms. I sent Leeson an email as well asking about the motors ability to govern itself.
  #55  
Old 12-24-2018, 05:49 PM
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Quote:
Originally Posted by Functional Artist View Post
...where Sid said "since what the motor COULD draw is exactly the amount the motor WILL draw if it needs to."

...& I also remember him telling me/us (one time or another) that a motor is simply a power convertor.
(it turns electrical energy into mechanical/rotational energy)
...kinda like a light bulb converts electrical energy into luminous/light energy
....
Yes, but let me emphasis this part:
"since what the motor COULD draw is exactly the amount the motor WILL draw if it needs to."
If the current demand on the motor is low..
the drawn power will be too..
(cruising is still an option with powerfull motors )

Quote:
Originally Posted by Functional Artist View Post

Think about it this way:
If a 60W light bulb connected to a 110V power supply will emit X amount of light
…& a 75W bulb connected to the same voltage power supply will emit Y amount of light
…& then, a 100W bulb also with the same voltage power supply will emit Z amount of light.
(each convertor happily drawing exactly what it needs)

You see, (again, if I'm understanding this correctly)
...a larger convertor (motor or light bulb) will produce more...rotational or light energy, from the same power supply.

Does this make sense?
Kindof.. but a Lightbulb is a bad comparision really..
once On it tries to draw as much as it can and while it can be limited (dimmed) actively.. it sucks as much power as it can at all times..

unlike a motor that draws as much power as it NEEDS
(only) up to it's internal limits if so required (load)
And while that's a fuzzy line really (constant, peak, with and w/o active cooling etc)
motors with less or even no load draw less currents than the exact same motor under significant load at the same speed.

It's even worse actually.. a higher power motor at the same load can run more efficient (and thus draw LESS current) for the same mechanical output power than a motor that is on the edge of it's capability under the otherwise exact same conditions.

But assuming the power supply fullfills the demand of both motors reliably
(say a [constant] 100A for either a 20 or a 60Amp motor)
the 60Amp motor of course delivers a bigger punch if needed
but only if needed.. if not it doesn't make any significant difference really.

Most motors have limits by means of RPMS.. well all do in fact..
but it's the simpler idea that we care about the most.
1) commutation (3+ phased Brushless motors need a pulsed signal.. and they can only run as fast as the controller can switch)
2) brushed motors commutate as fast as they turn and are limited by the physical limitations of their windings.
current must rush through, create a magnetic field, that has to interact with another field (of the permanent magnets usually),
those forces have to move the rotor until the commutator toggles the coils...
if little that still takes time.. and different coils (number of windings, wire gauge etc)
have different specs in that regard and that's usually the limiting factor for brushed PM DC motors.
(there's also loss due to resonating frequencies in brush springs, limiitations by bearings .. air resistance and so on and so forth... but that'd take things way too far for a forum like this I guess )

Essentially it's best to pick the motor for the task.. just mildly oversized
(to keep it from reaching it's limits too frequently)
a more powerfull motor means a quicker (not necessarily faster) setup with more acceleration..
and that's tempting to draw more power...
so you might end up using more battery juice for no other reason than grin
(more batteries more weight.. higher demand.. an the dog bites it's tail)

'sid
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  #56  
Old 12-25-2018, 08:00 AM
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Originally Posted by itsid View Post
Yes, but let me emphasis this part:
"since what the motor COULD draw is exactly the amount the motor WILL draw if it needs to."
If the current demand on the motor is low..
the drawn power will be too..
(cruising is still an option with powerfull motors )


Kindof.. but a Lightbulb is a bad comparision really..
once On it tries to draw as much as it can and while it can be limited (dimmed) actively.. it sucks as much power as it can at all times..

unlike a motor that draws as much power as it NEEDS
(only) up to it's internal limits if so required (load)
And while that's a fuzzy line really (constant, peak, with and w/o active cooling etc)
motors with less or even no load draw less currents than the exact same motor under significant load at the same speed.

It's even worse actually.. a higher power motor at the same load can run more efficient (and thus draw LESS current) for the same mechanical output power than a motor that is on the edge of it's capability under the otherwise exact same conditions.

But assuming the power supply fullfills the demand of both motors reliably
(say a [constant] 100A for either a 20 or a 60Amp motor)
the 60Amp motor of course delivers a bigger punch if needed
but only if needed.. if not it doesn't make any significant difference really.

Essentially it's best to pick the motor for the task.. just mildly oversized
(to keep it from reaching it's limits too frequently)
a more powerfull motor means a quicker (not necessarily faster) setup with more acceleration..
and that's tempting to draw more power...
so you might end up using more battery juice for no other reason than grin
(more batteries more weight.. higher demand.. an the dog bites it's tail)

'sid
Just tryin' to put things into terms everyone can easily understand.

OK, so it's more like how a 350W, a 500W & a 750W motor will all have around the same top speed when operated at the same voltage.

It's just that as the wattage gets larger (beefier motor), the motors can accelerate quicker while not having to work as hard, but carrying the same load.

Kinda like the "Hold on to your Hat Tests" showed

http://www.diygokarts.com/vb/showthread.php?t=39287

When I tried (2) different speed controllers & even a test without a speed controller
...& the top speed was the same all (3) times.

* the secret: it was the same 1,000W motor in all (3) tests
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  #57  
Old 12-25-2018, 09:22 PM
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NO, not really..

What I said is not only meant for a fixed voltage between different motors,
but also for a fixed voltage for any single motor at all times (except OFF).

While it's true that most (if not all) PMDC motors run at different speeds at different voltages,
that is NOT how you speed control a motor (other than in toys at times)

And it doesn't matter if the 350 and the 700W motor have the same rotational speed at the same voltage or not...
it has NOTHING to do with their power output.

And no a more powerfull motor doesn't need to accelerate quicker either
(it mostly can.. but it doesn't HAVE to !)

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  #58  
Old 12-26-2018, 11:43 AM
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To simmer this down a bit, if this particular Leeson motor is capable of drawing more power, then the improvement for Quinc would come from shorter gearing (numerically lower ratio) to increase the load and improve top speed without turning the motor any faster.
Is that reasonable to believe, based on what I'm understanding from the above posts?
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  #59  
Old 12-26-2018, 12:33 PM
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Quote:
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To simmer this down a bit, if this particular Leeson motor is capable of drawing more power, then the improvement for Quinc would come from shorter gearing (numerically lower ratio) to increase the load and improve top speed without turning the motor any faster.
Is that reasonable to believe, based on what I'm understanding from the above posts?
We are going to find out soon! I have some larger motor sprockets on the way.
New sprockets coming: 12T(30mph) 15T(38mph) and 18T(45mph)

https://www.surpluscenter.com/Power-...ore-Sprockets/
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Old 12-27-2018, 02:51 AM
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Quote:
Originally Posted by sikbrik View Post
To simmer this down a bit, if this particular Leeson motor is capable of drawing more power, then the improvement for Quinc would come from shorter gearing (numerically lower ratio) to increase the load and improve top speed without turning the motor any faster.
Is that reasonable to believe, based on what I'm understanding from the above posts?
that is a very reasonable assumption yes.

assuming both motors have about the same max rpm on their label, that is most certainly the case

A slightly higher gearing and still enough oomph to propell the vehicle.
One could (as always) also opt for a quicker acceleration instead of higher speeds.. but that's personal preference again

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