Rix said:
Hyena has a line of Chinese cromotor type clones. I believe those motors are running a 3 turn stator because of how fast they are. I speculated that those motors were good for about 35-37MPH with 12s which Hyena agreed based on him getting 60+MPH with 24s. Greybog lists the Cromotor with a 24"MTB wheel at 29MPH with 50 volts on their website. I don't think there is a cromotor, or a cro clone out there with a 5 turn stator.
Just because it's not widely known to the ES community yet doesn't mean a certain person who's been testing faster motors isn't having slower ones wound as we speak. This person is looking at offering them as a package with raptor frames but might just have a few left over for others too :wink:
The TC65 at 70-90v really shines, what I'm looking at is basically a bigger version of that that's more easily laced into moto rims.
Rix said:
If you plan on keeping voltage in the 50-80 volt range, you will not benefit much from a 5 turn stator over a 4 turn stator on the cromotor.....in my opinion.
We're probably better to talk in terms of faster or slower wind motors (or kv) rather than actual turns as it will vary between motors of different width and size. But yes, 50v on a 5 turn motor like the 540x makes for rather underwhelming top speed but it'll be virtually indestructible. Look at the motor efficiency curves, if you're riding a faster wind motor on slow twisty stuff you're at a very low part of the motors efficiency curve and you'll heat up the motor pretty quickly. A slower wind motor I reckon 72/80v is the sweet spot for these sorts of motors though in terms of performance and efficiency. For those that don't want to break the sound barrier and are happy with a top speed of around 60kmhr/37mph. And lets be honest, for actual proper mountain bike trail type riding that's plenty fast enough. If you want to go faster continuously (eg more open fire trails etc) then higher voltage or a faster wind motor is more appropriate.
It's the old story of choosing the best tool for the job, and unfortunately with a lack of gearing available on direct drive motors you need to pick a wind and voltage suitable to how you ride most of the time. They are somewhat 'one size fits all' and sure you can get great torque from a fast wind motor down low but the trade off is you have to throw heaps of current at it which quickly heats up the motor.
I had PM from someone saying they didn't understand what I was saying so here's an example from the ebikes.ca simulator that hopefully makes it more simple.
It's using the H3525 and H3545. These are obviously a smaller motor but it highlights the point of how the same motor in 2 different winds and fed different voltages behaves differently.
I've used a speed of 35km/hr / 22mph which I find is an average sort of speed you're likely to be riding mtb singletrack type stuff. Obviously you burst higher speed on straights and drop lower under brakes in the corners, but yeah, it's just as an average.
Look at the efficiency difference between the 2 motors. Motor A, the slower wind at 60v with a 70A controller is pulling just shy of 2000w. Motor B is the same motor but wound for higher speed, using the same controller but and with a 80v battery. This is vaguely more equivalent to the sort of thing most of the guys who are cooking motors are running. The faster wind motor is drawing a huge 5300w to do the same speed on this single track! More than 2.5 times the power and efficiency is only 54% vs 74%. If you've got a small battery you may flatten it before you cook the motor but on a raptor with a belly full of lithium it's RIP motor. If this is the sort of riding you want to do then motor A is the clear winner.
