What's the advantage of high T (winding) motor

[Timpo]

Okay so, I was not sure if high T motors actually produced more torque (which would be better for hill climbing, etc), but somebody on Endless Sphere said it's not the case.

Explain motor winding counts

I have been seeing these 6x9 4x4 8x10... numbers floating around to describe the windings on motors. I think I understand what this means, but I'd like a confirmation. A 6x9 motor is a 6 turn motor, meaning 6 turns of each wire wrapped around the stator. In this case there are 9 wires. More...

endless-sphere.com

Yes, I know forums cannot always be a reliable source of information.

And I went on Grin website to get more reliable information, and it said, "The Grin All-Axle Motor is currently produced with three different windings; a slow 8 turn stator, a standard 6 turn stator, and a fast 5 turn stator. All three motor winds are capable of producing exactly the same torque and power outputs so the recommended motor model depends on youre desired vehicle speed."

All-Axle Hub Motor - Grin Products - Product Info

The All Axle motor takes the simplicity and robustness of the direct drive hub motor, and optimizes it for the modern bike platform. This hub is fully compatible with all quick release and thru-axle bike forks, it is over 30% lighter than standard generic hubs of similar power (4kg vs 6kg), and...

ebikes.ca

If that's the case, what's the point of having high T motor?

It seems like high T motor will only give you low rpm, and won't give you any more torque than low T motor.

It seems like high T motor is just inferior version of low T motor.
What's the advantage of high T motor?

 

[onlineaddy]

As stated on that page you shared:

...the recommended motor model depends on youre [sic] desired vehicle speed. The faster wind motors are more appropriate for small wheel diameters and/or lower battery voltages, while the slower motor winds are more common with larger wheel sizes and higher battery voltages.

Also, some people don't need or want the higher speeds afforded by the fast windings, which will be more thirsty when it comes to battery consumption.

 

[AHicks]

I don't know right where you are looking, but my wild guess would be that the motor rpms where the torque reading are taken will be different, and correspond directly to the number of turns? Yup- check it out. See the chart in your second link.

USUALLY, they are going to suggest the lower turn/higher rpm motor for small wheels, and the highest turn/lowest rpm motor for larger wheels. However, there's nothing saying you can't get creative with their suggestions. If you have a special application, e.g. trying to see how fast you can go for instance, they'll lace up anything you ask them to. A "banana" bike for instance, with 20" wheels, should do some pretty nice wheelies easily with a high turn motor installed....

That's my take anyway. -Al

 

[AHicks]

Well that seems to be the case here.

Do people just get high T motor for low rpm just because they don't want to go too fast?

If that's the case, you could just get a low T motor for potential high speed (for off road, etc) you can just set your top speed 20mph, or whatever you like on display, as many ebikes can do.

The idea is to optimize the motor turns to the application.

It's kinda like selecting a camshaft for a target rpm in a 4 stroke. Anything done to increase power at high rpms generally comes at the expense of losses at low rpms.

In the case of my MAC 12t and my usage that has me using over 15mph only on rare occasions. There's no chance I would ever trade that 12t for an 8t. I have absolutely no use for any more speed than what I have.

I tried to copy and paste the chart I'm referring to, but it looses it's format and makes no sense. Look for the graph under "Motor SPEED". Here's the header:

Slow 8T Wind (7.5 rpm/V)​

Standard 6T Wind (10 rpm/V)​

Fast 5T Wind (12 rpm/V)​

 

[Yako]

I thought the winding determines where your Max power/torque comes. Like a sweet spot. On my bike it’s at 15-25kmh which isn’t where I need it, it’s at 8-10kmh when I think I’m about to die on a nasty climb.

 

[AHicks]

Well, let's drag out our handy dandy Grin Motor Sim Tool, set it up, and see what it tells us!

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

Have a look at starting torque, how the 2 compare for efficiency at different speeds, and how they compare for available power at different speeds. It's all easily read right there. Look at the differences on the bottom of the sheet as well.....

 

[kmccune]

I say watts in, watts out, there are many things that determine suitability of motor given the application as AHicks sez, you usually trade one for the other,I would imagine a motor with less turns would be a bit lighter, without getting into reluctance, counter EMF and things of that nature. Sort of like a "Formula One engine" lots of torque and power available at high RPM( naturally aspirated) make a little racer go extremely fast, wouldn't work good in a pickup, where a less powerful but low end torque engine would be the ticket.
Besides just take Justins word for it( He has done the heavy lifting, hmm, maybe Neal DeGrasse Tyson would be a good consultant).
'

 

[indianajo]

My Mac12t used about 2/3 the watthours of a regular (probably 10t) ebikeling over my 27 mile commute. As ebikeling was redlighting & cutting power on the last hill, the efficiency allowed me to add 3 miles & 20 more hills to stay off 3" berm fast traffic State 3.
12t gets me & 60 lb groceries across a 6 lane highway before the light turns yellow. 10t was slower accelerating. Torque happens at lower speed, which is important for not hitting the red light. I cross that highway twice in my commute. With a 48 v battery charged to 54, the Mac12t will go ~23 mph on the flat. Fast enough for a no suspension 2.1" tire bike. I hit 35 downhill when the pavement is perfect and no gravel, but that kind of pavement is rare in Clark Cty. Ebikeling motor would hit about 25 mph. I sit upright and cause a lot of air drag, to protect my neck disks.

 

[tomjasz]

I still don't understand.

No surprise.

 

[AHicks]

So the higher T motor will actually be more torquey?

This is the part I'm a little confused about, as they all produce the same amount of torque.

Clearly, they do NOT produce equal amounts of torque. If you could take just a second to click on the link I posted above (post #9), you could see exactly what the the difference in torque might be. I don't know how that point could be made any more clear? There's a MAC 12t and 8t all laid out for you. Lots of relevant info regarding comparable power usage, speeds, and time to overheat in the charts going across the bottom.

You can see this same kind of thing going on with the "rpm" ratings provided in some specs as well. The higher rpm motors have fewer turns than the same motor rated for fewer rpms.