Computer Dan said:
Well with these Currie motors that has been my experience which I never understood.
That has to do with the way they're wound, then. Or if they have a gearbox, the gearing it has inside. Or both.
The wattage ratting doesnt' mean much (see previous posts), but in general is about how much heat the motor can handle / get rid of.
Speed doesn't really have much to do with the watt rating, directly, but it does take more watts to go a faster speed, mostly due to air resistance.
The 900w motor is nearly impossible to turn the gear and shaft by hand. Makes pushing the bike really difficult as well.
This probably indicates a problem with that motor. Either something is wrong in the gearbox, or in the motor itself.
It could just indicate that it has a very high gear ratio, and a winding that creates a lot of current (drag) in it when spun at a high speed without power. That might be why it has such a slow speed...but it probably doesn't overheat.
Trying to find out what is the best controller to run 36V on a 24V motor. I noticed that the 40A controller I have is way more responsive and gets instant power. Wasn't sure if I should go to a 36V controller to run more efficient and if I should keep the amps down in order to keep from overheating if that indeed is a big contributor.
Well, you're talking about several completely different things, so you must decide which of those things you want the system to do, then get a controller that does those things.
First, if you have a "900w" motor, and it's at 36v, then the highest curretn you should continuously allow is 900 / 36 = 25A. So to prevent overheating, you should be runnign a 26A controller.
If you have a 450w motor, that would be a 13A controller.
That's assuming the motors are "rated" as the max continuous amount of power they can dissipate as heat, vs teh gearing they are designed for and actually used at, vs teh speed they are designed for and actually used at, vs the load they are designed for and used at.
If they're being used differently than designed, you'd have to experiment with overheating vs power in vs usage (which you're doing now), and if they're getting hot, then you're putting too much power thru them (too high a controlelr current limit) for the gearing and usage you have.
Regarding how quickly teh controller responds, that's just the type of controller throttle response. Some are "soft start" and some are "instant start". Most sellers dont' provide this information, and some have it wrong (or are sending a different thing than the ad says), so i'ts possible to get the wrong kind easily enough.
Regarding the simulator...its the only easy way I know of to show you why you're having the problems you are, because there are a lot of factors to it. It takes a certain amount of power to do a certain amount of work, and it makes certain amount of waste heat to do this dependign on the system you use and how you use it, what speed you're at, your gearing, the load, the wind, the slope, etc. There is at least one thread on the simulator, that helps explain it, if that's useful.
https://endless-sphere.com/forums/viewtopic.php?f=3&t=30108&hilit=simulator
https://endless-sphere.com/forums/viewtopic.php?f=2&t=89877&hilit=simulator
https://endless-sphere.com/forums/viewtopic.php?f=2&t=100461&hilit=simulator
and a number of other threads
https://endless-sphere.com/forums/search.php?keywords=simulator&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
You can read about all this stuff individually, if it helps; theres' threads here about it, and other websites you can find. But without knowing how this works, you're kinda stuck just using experimentation to find a solution.