Do some motors have more/less torque with the same power levels?

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speedyebikenoob   1 kW

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Do some motors have more/less torque with the same power levels?

Post by speedyebikenoob » Apr 30 2021 10:41am

I'm shopping for a new motor and I'm quite confused on the amount of torque a motor has. In my case, my old motor was a mini cyclone or cyclone 1680w and I'm looking to upgrade to the 3 kw cyclone. I keep hearing that the cyclone 3000 has a lot more torque.

If I use the same power motor controller on the cyclone 3000 as I did on the mini, and I gear it to have the same top speed in each gear as my mini, why would the cyclone 3000 have more torque? Where does that extra torque even come from?

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Re: Do some motors have more/less torque with the same power levels?

Post by speedyebikenoob » May 01 2021 1:46pm

No one knows? :(

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Re: Do some motors have more/less torque with the same power levels?

Post by spinningmagnets » May 01 2021 4:32pm

It's possible to saturate the stator of a certain size of motor, and any additional power that you add will only be converted to waste heat.

So...its possible that at a certain power level, a larger motor could make full use of the input watts, where a smaller motor would make less power when using the same input watts.

There are also many other factors. Do you want to compare two different styles of motor that are the same physical size?

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Re: Do some motors have more/less torque with the same power levels?

Post by markz » May 01 2021 5:19pm

Interesting question

Same motor but with 72V 25A = 1.8kw power = more speed at w.o.t. then 45V and less initial torque at 25A then 60A.
Same motor but with 45V 40A = 1.8kw power = less speed at w.o.t. then 72V and more initial torque at 40A then 40A.


Wide Open Throttle, both 1800W 72V x 25A vs 45V x 40A
https://ebikes.ca/tools/simulator.html? ... &throt=100

Same Speed, both 1800W 45V x 40A vs 72V 25A
https://ebikes.ca/tools/simulator.html? ... throt=58.2

edit
Changing the variables a tad more, why turn count and kv dont mean a speed motor or a torque motor, no they both have the same speed, both have the same torque at a certain throttle. The 3T has higher speed potential at WOT then 6T.
3T vs 6T mxus 45H motor (3kw motor)
Pretty closely matched, more voltage and more amps with a tad less resistance with lots of room on the throttle @ 20% to go faster = less voltage and less amps with more resistance with throttle at 60% so less room to go faster. Key is whats the fastest you want to go?
https://ebikes.ca/tools/simulator.html? ... throt=19.4
Last edited by markz on May 03 2021 9:47pm, edited 5 times in total.

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Re: Do some motors have more/less torque with the same power levels?

Post by sn0wchyld » May 03 2021 10:51am

speedyebikenoob wrote:
Apr 30 2021 10:41am
I'm shopping for a new motor and I'm quite confused on the amount of torque a motor has. In my case, my old motor was a mini cyclone or cyclone 1680w and I'm looking to upgrade to the 3 kw cyclone. I keep hearing that the cyclone 3000 has a lot more torque.

If I use the same power motor controller on the cyclone 3000 as I did on the mini, and I gear it to have the same top speed in each gear as my mini, why would the cyclone 3000 have more torque? Where does that extra torque even come from?
Geared to the same top speed, you'll have very similar torque levels, assuming your controller controls the phase amps (most do)
if the motor is more efficient, you might see a bump in output, though the inverse is also true.
Upgrade the controller and you'll see a benefit.
torque and power are inescapably linked. the only thing you can do for a given power input is improve the efficiency such that more of it reaches the ground rather than getting wasted as heat.

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Re: Do some motors have more/less torque with the same power levels?

Post by Triketech » May 03 2021 11:31am

Basic electronics tells us that winding counts will impact torque and voltage constants.

Voltage Constant isn't the battery voltage its the voltage level a motor produces over a given RPM range.
Torque Constant is the amperage required to produce a given level of torque.
Both are generally linear Constants.
More turns increase the Voltage Constant with a generally proportional decrease of current due to the resistance and inductance increases (think longer wire).

So lets say you have a 48V battery and a motor that reaches 48V "Bias Voltage" at 200 RPM. The battery can't push any amps into the motor at 200 RPM. At 100 RPM the motor has a 24V Bias Voltage with 24V to spare to force current. Without current limits to the FETs the motor may accept 100+ amps.

Keep in mind that the battery voltage can supply 48V so when a motor starts from zero the electromagnets still see up to 48V minus Resistivity losses.

Which brings us back to power level. Depending on windings the motor either runs faster with less torque or slower with more torque. The power (think Horsepower) doesn't change.

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Re: Do some motors have more/less torque with the same power levels?

Post by sn0wchyld » May 03 2021 2:33pm

Triketech wrote:
May 03 2021 11:31am
Basic electronics tells us that winding counts will impact torque and voltage constants.

Voltage Constant isn't the battery voltage its the voltage level a motor produces over a given RPM range.
Torque Constant is the amperage required to produce a given level of torque.
Both are generally linear Constants.
More turns increase the Voltage Constant with a generally proportional decrease of current due to the resistance and inductance increases (think longer wire).

So lets say you have a 48V battery and a motor that reaches 48V "Bias Voltage" at 200 RPM. The battery can't push any amps into the motor at 200 RPM. At 100 RPM the motor has a 24V Bias Voltage with 24V to spare to force current. Without current limits to the FETs the motor may accept 100+ amps.

Keep in mind that the battery voltage can supply 48V so when a motor starts from zero the electromagnets still see up to 48V minus Resistivity losses.

Which brings us back to power level. Depending on windings the motor either runs faster with less torque or slower with more torque. The power (think Horsepower) doesn't change.
Factor your missing in this is that the bike is geared to the same top speed/no load rpm... so the 'wheel speed' kv (or kQ) of the motor ends up being the same, hence the torque produced at the wheel also ends up being the same, even for 2 motors with different kV/kQ.

Think a 10kV motor on a 100V pack. It'll spin at ~1000rpm
now think of a 20kv motor on the same 100v pack. It'll spin at 2000rpm

motor 1 will have a torque constant around 0.9Nm/A - so with a controller limited to say, 100phase amps it'll produce about 90Nm.
Motor 2 will have a torque constant around 0.45Nm/A - so with the same controller @ 100 phase amps, it'll put out about 45Nm.
But as the OP said... its geared to the same top speed, so that 45Nm at 2000rpm, gets geared to 90Nm at 1000rpm.

Basically, the gearing means that the torque per amp at the wheel is exactly the same. You could have a tiny 3000kV RC motor and a 5kV direct drive hub... if they spin to the same wheel RPM no load, then the kV, kQ end up being exactly the same too, as far as working out the the wheel torque. Efficiency might impact the end result, but otherwise, the same phase amps into each motor will produce the same wheel torque.

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Re: Do some motors have more/less torque with the same power levels?

Post by BobBob » May 03 2021 7:38pm

The bigger motor can potentially provide more torque or power without it overheating, but only if you provide it with more power.
You may have to upgrade your controller or battery to do so. The old motor might be limiting the power

If you put in 1.8 KW then you will get out 1.8 KW, some of it as heat There's no beating conservation of energy.

For a more in depth understanding and to see whether your system is likely to be limited in certain conditions by the controller battery or motor, I'd suggest you Use the Grin simulator that Markz put a link to https://ebikes.ca/tools/simulator.html? ... throt=58.2, and check how the different variables affect each other.


Further detail if you are interested
Try playing with the options for 8T or 10T in the grin simulator.
If there are any different winding options for your motor, you could try them with your controller and battery.
It might help by trading volts for amps if that is all you need to do, (difficult to explain - recommend play with it)

There will be a maximum torque limit at low speed due to controller and battery amps or the motor resistance
There will be a maximum speed limit due to voltage driving the current through the motor coils and back EMF

If the wire's too thin or the voltage too low or the controller can't keep up with either (volts or current) or you're in too high or low a gear it will slow you down

Peak efficiency for a given voltage is typically around 85% of the unloaded speed but max power output might be 65% and you might want to use mechanical gearing to use either or somewhere in between - probably the maximum efficiency with sufficient power
Driving the motor with different volts or windings doesn't help efficiency much but a faster spinning motor is often more efficient

If you have bigger thicker wires, more copper in your windings, run the motor at a higher speed by changing gear then you will probably get better efficiency
Last edited by BobBob on May 04 2021 11:12am, edited 3 times in total.

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Re: Do some motors have more/less torque with the same power levels?

Post by Triketech » May 04 2021 10:08am

sn0wchyld wrote:
May 03 2021 2:33pm

Factor your missing in this is that the bike is geared to the same top speed/no load rpm... so the 'wheel speed' kv (or kQ) of the motor ends up being the same, hence the torque produced at the wheel also ends up being the same, even for 2 motors with different kV/kQ.

Think a 10kV motor on a 100V pack. It'll spin at ~1000rpm
now think of a 20kv motor on the same 100v pack. It'll spin at 2000rpm

motor 1 will have a torque constant around 0.9Nm/A - so with a controller limited to say, 100phase amps it'll produce about 90Nm.
Motor 2 will have a torque constant around 0.45Nm/A - so with the same controller @ 100 phase amps, it'll put out about 45Nm.
But as the OP said... its geared to the same top speed, so that 45Nm at 2000rpm, gets geared to 90Nm at 1000rpm.

Basically, the gearing means that the torque per amp at the wheel is exactly the same. You could have a tiny 3000kV RC motor and a 5kV direct drive hub... if they spin to the same wheel RPM no load, then the kV, kQ end up being exactly the same too, as far as working out the the wheel torque. Efficiency might impact the end result, but otherwise, the same phase amps into each motor will produce the same wheel torque.
The OP question pertained to the motor not the motor driver, but point taken.

The gear ratio difference also brings up the topic of efficiency. At half RPM one motor will be less efficient than the other at lower speeds. Pole switching frequency plays a huge role in efficiency levels at low speeds so the "Slow Wind" motor converts more power to heat. Efficiency loss is quantifiable on a case by case basis.

As for real world testing on a MAC 10T, wife & I have a pair of Scorpion FS26's, Phaserunners, CA3's+ Data. One is 36V one is 48V. Our typical pace is about 14 MPH average, 4-6% average grades (with a sustained 500 foot climb over a mile). The 36V motor typically runs about 20° hotter at the end of a ride. I've swapped everything around to see if its the motor, motor driver and rider. Nope. The 36V is less efficient for our ride profile, and even with the same gearing and current limits doesn't have much more torque at lower speeds, and consumes about 15-20% more more power than the 48V.

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Re: Do some motors have more/less torque with the same power levels?

Post by BobBob » May 04 2021 11:44am

Triketech wrote:
May 04 2021 10:08am
The gear ratio difference also brings up the topic of efficiency. At half RPM one motor will be less efficient than the other at lower speeds. Pole switching frequency plays a huge role in efficiency levels at low speeds so the "Slow Wind" motor converts more power to heat. Efficiency loss is quantifiable on a case by case basis.
Are you comparing the OP's old and new motor here which will be different sizes, copper fill as well as wind or two identical motors with different winds?
Small diameter motors with fewer poles will be more efficient at higher RPM whereas the same sized motor with different winds will be pretty similar if driven at the same RPM with different voltage and current to match the winds.
Just so we don't confuse the OP :)
Triketech wrote:
May 04 2021 10:08am
As for real world testing on a MAC 10T, wife & I have a pair of Scorpion FS26's, Phaserunners, CA3's+ Data. One is 36V one is 48V. Our typical pace is about 14 MPH average, 4-6% average grades (with a sustained 500 foot climb over a mile). The 36V motor typically runs about 20° hotter at the end of a ride. I've swapped everything around to see if its the motor, motor driver and rider. Nope. The 36V is less efficient for our ride profile, and even with the same gearing and current limits doesn't have much more torque at lower speeds, and consumes about 15-20% more more power than the 48V.
If both are the same MAC 10T but driven with different voltages, it will be partly the controller or wiring. Copper losses would be greater for higher current due to lower voltage to maintain the same overall power.
Solution thicker wire for the 36V motor? 15-20% seems a lot though and the motor getting hotter is strange.
hmm

Is is possible that with a 36V setup you are running the motor at lower RPM and higher torque for max power output and changing gear to suit?

Just a hypothesis that fits the info

This simulation gives the 25% you said for battery power used
The 36V is going flat out but the 48 can run at a more efficient speed so the gearing is different.
Motor power output identical, speed identical but the 36V overheats. i love that Grin simulator
https://ebikes.ca/tools/simulator.html? ... b=1&gear=1
Efficiency from higher volts.JPG
Efficiency from higher volts.JPG (180.27 KiB) Viewed 415 times
Last edited by BobBob on May 04 2021 12:34pm, edited 1 time in total.

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Re: Do some motors have more/less torque with the same power levels?

Post by RTLSHIP » May 04 2021 12:33pm

A smaller wheel diameter should give you more torque and less top speed than a bigger wheel. It depends on where you live or what you want to do. For hills, a smaller wheel is preferred. So each motor could be identical, yet power is delivered differently due to physics/leverages.
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Re: Do some motors have more/less torque with the same power levels?

Post by speedyebikenoob » May 04 2021 1:41pm

So it's as I thought then. If they are geared to the same max speed (meaning the winding is irrelevant, right?) and powered with the same controller, they should have the same performance, unless one motor is more efficient than the other. In which case the more efficient motor will have better performance because less power is being wasted by turning into heat.

Am I missing anything here?

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Re: Do some motors have more/less torque with the same power levels?

Post by BobBob » May 04 2021 1:53pm

speedyebikenoob wrote:
May 04 2021 1:41pm
So it's as I thought then. If they are geared to the same max speed (meaning the winding is irrelevant, right?) and powered with the same controller, they should have the same performance, unless one motor is more efficient than the other. In which case the more efficient motor will have better performance because less power is being wasted by turning into heat.

Am I missing anything here?
That they can be spinning at different speeds and overheating - you can put double the power through the 3 Kw

If the bike and motor were going at the same speed and the only difference between the motors was number of windings and the voltage and current trade off were according to the difference in windings then the windings would be irrelevant.
If you only change the windings and you change the battery configuration then you get exacty the same performance.

In your example we might have to look in a bit more detail at exactly what differs and what you want out of it and what you are prepared to change for an improvement. There are quite a few things to potentially change and they may affect each other differently at different speeds

The motor could be different due to it's size, the amount of copper fill, number of poles etc. Are you able to find out the spec of the two motors and plug them into the grin simulator?
We can then get some better numbers and work out how yours system might actually behave.
I had a quick look and couldn't see the Cyclone.

Are you after more power, more top speed, less overheating, better efficiency, better range?

As you have gears you can be travelling at the same speed but the motor could be spinning at a different speed and the efficiency gains for that can be significant - see my post two posts up. one motor is using 25% more power and overheating in a couple of minutes but it's an identical motor and the bike is going at the same speed.

Changing the windings only, to allow the motor to spin at a different speed, might also have a similar effect - largely due to the efficiency difference due to the motor speed. (Again as this sometimes gets misunderstood, if the motors were spinning at the same speed and otherwise identical, other than windings, then changing the windings wouldn't help efficiency at that speed and you just trade volts for amps to paraphrase Justin)
Last edited by BobBob on May 04 2021 3:21pm, edited 4 times in total.

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Re: Do some motors have more/less torque with the same power levels?

Post by BobBob » May 04 2021 2:20pm

With nothing but mechanical gear and winding changes, bike b is going faster while using less power, and not overheating, due to better efficiency due to the motor spinning faster.

https://ebikes.ca/tools/simulator.html? ... b=1&gear=1

Current not limited
windings + gearing.JPG
windings + gearing.JPG (188.59 KiB) Viewed 392 times
battery current at around 40A from phaserunner - similar result from standard controller
https://ebikes.ca/tools/simulator.html? ... b=1&gear=1

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Re: Do some motors have more/less torque with the same power levels?

Post by Triketech » May 05 2021 5:19pm

BobBob wrote:
May 04 2021 11:44am

If both are the same MAC 10T but driven with different voltages, it will be partly the controller or wiring. Copper losses would be greater for higher current due to lower voltage to maintain the same overall power.
Solution thicker wire for the 36V motor? 15-20% seems a lot though and the motor getting hotter is strange.
hmm
Is is possible that with a 36V setup you are running the motor at lower RPM and higher torque for max power output and changing gear to suit?
Copper losses account for some but not all, and it happens with both controllers, each time swapped the Phaserunners were paired. 12AWG battery to Phaserunner (10") 14AWG to Hub (21"), 14AWG internal.

The MAC is like a Direct Drive with a 5:1 ratio. Here is the inside view:

Image
Image

This may drift a bit off the topic but its often overlooked between a MAC and DD:
With 36 poles and 5:1 gearing, the poles are switched 180 times per revolution ("Virtual Rotor Speed") . For a 26" tire that comes to 1 pole switch every .45" of travel. Compare that with a Direct Drive 48 pole (with larger OD & weight) of the same power rating, with a pole switch every 1.74" of travel. That shorter distance of pole switching increases efficiency and torque significantly.

The Efficiency Curve for a BLDC starts at 0 RPM, so if you throw 100 amps and the motor isn't turning efficiency is zero. Efficiency will continue to increase with RPM until the core approaches a "Soft Saturation" level where residual fields remain into the following switching cycle. Yep, its that simple.

The simulator is a great tool but it gives trend level data, sometimes quite accurate, sometimes not. I see that in just about every simulator out the from circuit design, to stress modeling to thermal modeling tools.

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Re: Do some motors have more/less torque with the same power levels?

Post by markz » May 05 2021 8:50pm

Do not play the efficiency game with hub motors. Its not a significant role.

There are other factors to consider like price, weight, power, range and battery.


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Re: Do some motors have more/less torque with the same power levels?

Post by E-HP » May 05 2021 10:47pm

speedyebikenoob wrote:
Apr 30 2021 10:41am
I'm shopping for a new motor and I'm quite confused on the amount of torque a motor has. In my case, my old motor was a mini cyclone or cyclone 1680w and I'm looking to upgrade to the 3 kw cyclone. I keep hearing that the cyclone 3000 has a lot more torque.

If I use the same power motor controller on the cyclone 3000 as I did on the mini, and I gear it to have the same top speed in each gear as my mini, why would the cyclone 3000 have more torque? Where does that extra torque even come from?
Basic physics, lever arm on the bigger motor is bigger than the smaller motor. Similarly, and an interior rotor motor, like mid-drives use, versus an exterior rotor motor, like hub motors have more torque potential. "r" is a lot bigger.

Interior rotor motors can spin a lot faster, since that's the trade off.

EDIT: for the interior vs exterior rotor comparison, that would be comparing motors with similar exterior housings.

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Re: Do some motors have more/less torque with the same power levels?

Post by fatty » May 06 2021 3:56am

speedyebikenoob wrote:
Apr 30 2021 10:41am
If I use the same power motor controller on the cyclone 3000 as I did on the mini, and I gear it to have the same top speed in each gear as my mini, why would the cyclone 3000 have more torque? Where does that extra torque even come from?
It wouldn't. Torque is a function of torque constant (Kt) in Nm/A, amps, and gearing.
The Mini is geared with 9.55:1 primary torque multiplication, whereas the 3000 is geared with 6:1 primary torque multiplication, but the 3000 probably has higher Kt to compensate. So if you use the same controller with the same amps, it wouldn't have more torque -- they would be about the same.

The advantage to the 3000 (as with all larger motors) is that it can take more amps, and for longer, and thus make more torque (and thus power):
cyclone motors.JPG
cyclone motors.JPG (20.54 KiB) Viewed 289 times

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Re: Do some motors have more/less torque with the same power levels?

Post by E-HP » May 06 2021 10:35am

fatty wrote:
May 06 2021 3:56am
It wouldn't. Torque is a function of torque constant (Kt) in Nm/A, amps, and gearing.
The Mini is geared with 9.55:1 primary torque multiplication, whereas the 3000 is geared with 6:1 primary torque multiplication, but the 3000 probably has higher Kt to compensate. So if you use the same controller with the same amps, it wouldn't have more torque -- they would be about the same.

The advantage to the 3000 (as with all larger motors) is that it can take more amps, and for longer, and thus make more torque (and thus power):
cyclone motors.JPG
Depending on the power level, may need to consider saturation of the smaller motor vs the larger one. Once the motor saturates, it will draw a lot more current, so more power will go to heat than a larger motor pulling the same power, but not saturated.

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Re: Do some motors have more/less torque with the same power levels?

Post by Chalo » May 06 2021 1:31pm

RTLSHIP wrote:
May 04 2021 12:33pm
A smaller wheel diameter should give you more torque
No. Torque is independent of wheel diameter. What you're talking about is mechanical advantage, tractive effort, "thrust"-- but definitely not torque.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Re: Do some motors have more/less torque with the same power levels?

Post by fatty » May 06 2021 1:57pm

E-HP wrote:
May 06 2021 10:35am
Depending on the power level, may need to consider saturation of the smaller motor vs the larger one. Once the motor saturates, it will draw a lot more current, so more power will go to heat than a larger motor pulling the same power, but not saturated.
Theoretically, but this certainly isn't the case for noobs with kit controllers asking intro questions.

In fact, direct-drives and mid-drives, not being size-constrained, are current/temperature-limited, not flux-limited. I've only seen tiny geared hubmotors start to magnetically saturate at triple to 5x their rated current, and the phase insulation literally melted off anyway.
Last edited by fatty on May 06 2021 2:00pm, edited 2 times in total.

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Re: Do some motors have more/less torque with the same power levels?

Post by fatty » May 06 2021 1:58pm

Chalo wrote:
May 06 2021 1:31pm
No. Torque is independent of wheel diameter. What you're talking about is mechanical advantage, tractive effort, "thrust"-- but definitely not torque.
:thumb:
Hillhater wrote:
May 21 2020 9:03pm
Reducing the wheel diameter will reduce the speed, but does not change the “torque” (Nm) at the wheel, it simply reduces the “torque arm” , or the distance from the axle to the tire tread radius.(the “m” in Nm)
Since torque is ..Force X radius.., that reduction in radius , effectively increases the traction force (F), available at the tire/road surface....from the SAME Torque at the wheel hub

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Re: Do some motors have more/less torque with the same power levels?

Post by BobBob » May 06 2021 2:31pm

Triketech wrote:
May 05 2021 5:19pm
BobBob wrote:
May 04 2021 11:44am

If both are the same MAC 10T but driven with different voltages, it will be partly the controller or wiring. Copper losses would be greater for higher current due to lower voltage to maintain the same overall power.
Solution thicker wire for the 36V motor? 15-20% seems a lot though and the motor getting hotter is strange.
hmm
Is is possible that with a 36V setup you are running the motor at lower RPM and higher torque for max power output and changing gear to suit?
Copper losses account for some but not all, and it happens with both controllers, each time swapped the Phaserunners were paired. 12AWG battery to Phaserunner (10") 14AWG to Hub (21"), 14AWG internal.

The MAC is like a Direct Drive with a 5:1 ratio. Here is the inside view:

Image
Image

This may drift a bit off the topic but its often overlooked between a MAC and DD:
With 36 poles and 5:1 gearing, the poles are switched 180 times per revolution ("Virtual Rotor Speed") . For a 26" tire that comes to 1 pole switch every .45" of travel. Compare that with a Direct Drive 48 pole (with larger OD & weight) of the same power rating, with a pole switch every 1.74" of travel. That shorter distance of pole switching increases efficiency and torque significantly.

The Efficiency Curve for a BLDC starts at 0 RPM, so if you throw 100 amps and the motor isn't turning efficiency is zero. Efficiency will continue to increase with RPM until the core approaches a "Soft Saturation" level where residual fields remain into the following switching cycle. Yep, its that simple.

The simulator is a great tool but it gives trend level data, sometimes quite accurate, sometimes not. I see that in just about every simulator out the from circuit design, to stress modeling to thermal modeling tools.
Don't blame the simulation
In this case it was purely rubbish in rubbish out. Brain failed to change from OP mid drive to the MAC being a hub motor which I know really - I even considered getting one instead of my MXUS

It's an interesting off topic and I Dunno - Gremlins?
How about how fast you are actually going, I assume the 36V is slower so do you go at the same speed up a steep hill on the 48V?
If you zoom ahead and keep the 48V at a more efficient speed then stop and wait for the other cyclist on the 36v who keeps a constant and slower speed they would have a much hotter and so less efficient motor and possibly also be traveling at a less efficient speed? interesting puzzle - may go play with the sim again once my ego recovers a bit lol

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Re: Do some motors have more/less torque with the same power levels?

Post by Triketech » May 07 2021 8:43am

BobBob wrote:
May 06 2021 2:31pm

It's an interesting off topic and I Dunno - Gremlins?
How about how fast you are actually going, I assume the 36V is slower so do you go at the same speed up a steep hill on the 48V?
If you zoom ahead and keep the 48V at a more efficient speed then stop and wait for the other cyclist on the 36v who keeps a constant and slower speed they would have a much hotter and so less efficient motor and possibly also be traveling at a less efficient speed? interesting puzzle - may go play with the sim again once my ego recovers a bit lol
The 48V peak speed is about 29 MPH, the 36V is about 22 MPH. We normally ride about 10-15 MPH. Many steep grades where we ride, 10% climbs some over a mile long. We pretty much ride the same speed (mostly side by side) on the uphills & flats, but sometimes I'll see 35+ MPH on the downhills while my wife holds it down around 20 MPH. Yeah, we've swapped riders with the same results too.

Simulators are wonderful tools its the confidence factor that varies. For example could this be a calibration anomaly in the Phaserunner setup? That not a condition the GrinSim has any configurations for. Looking at the phase output waves between the 36V and 48V on a 3 channel O-scope the waveforms the 36V holds a higher residual charge, this is most likely the culprit.

I wrote this article about 5 years ago on the MAC. We've bought and tested about a dozen different systems over the years, but for our purposes nothing beats the MAC.

http://www.triketech.com/Drivetrain/Pow ... AC-V2.html

A few months back I replaced the LiFe battery with a Li_ion. I'm probably the only person who mounts the battery under the boom on a trike.

BobBob   100 W

100 W
Posts: 160
Joined: Sep 04 2020 8:21pm

Re: Do some motors have more/less torque with the same power levels?

Post by BobBob » May 07 2021 10:58am

Triketech wrote:
May 07 2021 8:43am
The 48V peak speed is about 29 MPH, the 36V is about 22 MPH. We normally ride about 10-15 MPH. Many steep grades where we ride, 10% climbs some over a mile long. We pretty much ride the same speed (mostly side by side) on the uphills & flats, but sometimes I'll see 35+ MPH on the downhills while my wife holds it down around 20 MPH. Yeah, we've swapped riders with the same results too.
OK, that scuppers my different speeds theory - I got to 18% difference but not at the grades and speeds you are talking about
https://ebikes.ca/tools/simulator.html? ... &temp_b=80
Triketech wrote:
May 07 2021 8:43am
Simulators are wonderful tools its the confidence factor that varies. For example could this be a calibration anomaly in the Phaserunner setup? That not a condition the GrinSim has any configurations for. Looking at the phase output waves between the 36V and 48V on a 3 channel O-scope the waveforms the 36V holds a higher residual charge, this is most likely the culprit.
In a previous job, I once flew to Germany to work on a simulation of a design of mine with our best simulation team. After four of us had worked on it for a week they advised I build one and test it instead. I still find them useful
Not sure what you mean about the residual charge. With a three channel you can potentially see where the power's going from voltage drops at different parts of the circuit during the PWM at different loads and speeds.
Should be able to see a change in ratio due to resistive loads, inductive, back EMF etc.
Faulty motor - compare with another of the same type?
Faulty calibration - can you get at the variables on the phaserunner? Can you check the calcs or put in manual settings?
Systemic measurement fault? - EG 36V battery tends to measure as higher current due to sensor heating up or something
Solution - convert both to 48V it's better?
Triketech wrote:
May 07 2021 8:43am
I wrote this article about 5 years ago on the MAC. We've bought and tested about a dozen different systems over the years, but for our purposes nothing beats the MAC.

http://www.triketech.com/Drivetrain/Pow ... AC-V2.html

A few months back I replaced the LiFe battery with a Li_ion. I'm probably the only person who mounts the battery under the boom on a trike.
Really interesting stuff and glorious scenery.
I'd heard the geared motors were noisier than DD with higher RPM and gears and went for the MXUS 3K partly for that reason - how do you think they compare? They seem pretty quiet in the videos
May use that frame clamp idea - thanks

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