Mini Cyclone Motor RPM

S

speedyebikenoob

1 kW
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Feb 6, 2019
Messages
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So I've been working on a tachometer for my e bike which is powered by a middrive mini cyclone motor. Before I did that though I just wanted to figure out what the maximum rpm of the motor actually is. It has a 13 tooth sprocket on the motor and the chainring it connects to is a 44 tooth. At the crankset in the front, I stuck a piece of orange tape on it and every time the tape passed a marked point on the bicycle frame I counted it as one revolution (used the slow motion feature on my phone to accurately count). After one minute, I got 268 rpm on the front sprocket. I calculated the ratio between the motor sprocket and the chainring and figured out the 13 tooth motor sprocket is turning at 907 rpm. Because the motor has a 9.55:1 gearing ratio, this means the motor is spinning at nearly 8700 rpm. Uh what? I thought the max for these motors was about 5000? Am I just doing the math wrong somehow or is that how fast this motor spins? This was through a 60 volt battery and the stock controller by the way. If someone who has a cyclone motor could clarify this for me it would be great, does your motor also rev that high?
 
No, you must have dilated the space/time continuum somehow. I keep telling people to be more careful with their cellphones. No one listens.

If you had, say, a 44t chainring driving an 11t rear sprocket at a ratio of 1 to 4, a 268 rpm at the cranks would net you 1072 rpm at the wheel which would be like, um, fast. Like really fast.

Somethin' ain't right!
 
fourbanger said:
No, you must have dilated the space/time continuum somehow. I keep telling people to be more careful with their cellphones. No one listens.

If you had, say, a 44t chainring driving an 11t rear sprocket at a ratio of 1 to 4, a 268 rpm at the cranks would net you 1072 rpm at the wheel which would be like, um, fast. Like really fast.

Somethin' ain't right!
Click to expand...

Oh, no by 13 tooth I didn't mean the rear sprocket, I meant the motor turns the crank with a 13 tooth sprocket, and the sprocket on the crank is a 44 tooth, so the sprocket on the motor would be turning about 900 rpm with the cranks at 268. The bike only maxes out at 37 mph so it's not insanely fast or anything but the 8700 rpm that the motor is supposedly turning from my calculations are a little sus, as I don't think a bbshd or even a normal cyclone 3000 spin that fast.
 
Right I got that bit and to be perfectly honest I have ZERO experience with these motors, so for all I know the thing really could be screaming its guts out at 8k+ rpm, but that just doesn't sound right to me.

What I'm saying is that, hypothetically, if you had a 44/44t crankset with one chainring being driven by the motor and the other driving the highest gear at the wheel then the wheel would be spinning at 1000+ rpm. That's no-load speed mind you (unless you were somehow able to take the video while you were actually riding, which would be at least somewhat impressive).

268 seems about right for the 13t sprocket on the motor (under load) but not for the crankset.

Could you explain again how you went about coming up with that number exactly? Did you record the rotation for a minute in real time then watch it in slo-mo for as long as it took for the video to finish? What I'm thinking right now is that if your phone used some kind of slowmo setting to RECORD the video rather than PLAYBACK the movie to you, then what you perceive to be 60 seconds may not actually be, and that would set your numbers somewhat... askew.
 
Aren't these motors rated 360 RPM no-load at 24V after reduction ? http://www.cyclone-tw.com/dc24.htm
Or 3600 RPM before reduction https://endless-sphere.com/forums/viewtopic.php?t=13423&start=31
- which means something around 150 RPM/V.
So 8500 - 9000 at 60V seems just right to me.
 
fourbanger said:
Right I got that bit and to be perfectly honest I have ZERO experience with these motors, so for all I know the thing really could be screaming its guts out at 8k+ rpm, but that just doesn't sound right to me.

What I'm saying is that, hypothetically, if you had a 44/44t crankset with one chainring being driven by the motor and the other driving the highest gear at the wheel then the wheel would be spinning at 1000+ rpm. That's no-load speed mind you (unless you were somehow able to take the video while you were actually riding, which would be at least somewhat impressive).

268 seems about right for the 13t sprocket on the motor (under load) but not for the crankset.

Could you explain again how you went about coming up with that number exactly? Did you record the rotation for a minute in real time then watch it in slo-mo for as long as it took for the video to finish? What I'm thinking right now is that if your phone used some kind of slowmo setting to RECORD the video rather than PLAYBACK the movie to you, then what you perceive to be 60 seconds may not actually be, and that would set your numbers somewhat... askew.
Click to expand...

Yup it wasn't under load, the wheel was off the ground, but judging by the pitch of the motor underload while it does get pretty close to whatever I was getting when it was off the ground. Here's what I did. I had someone twist the throttle to max for me while I held my phone and a stopwatch. I started recording in slow motion and then hit start on the stop watch, so I could see the time while watching the video back in slow motion, and that's how I counted it for a minute. I also do not think I messed up my counting because I triple checked and got the same result each time. Yeah I don't understand what I'm doing wrong either :lol: Although the motor is known for being one of the faster spinning ones, 8k+ rpm does sound a little much.
 
silence said:
Aren't these motors rated 360 RPM no-load at 24V after reduction ? http://www.cyclone-tw.com/dc24.htm
Or 3600 RPM before reduction https://endless-sphere.com/forums/viewtopic.php?t=13423&start=31
- which means something around 150 RPM/V.
So 8500 - 9000 at 60V seems just right to me.
Click to expand...

The motor I'm running is definitely more powerful than those, it's putting out 2400+ watts, I bought it off of the Luna Cycle site. I'm not even sure it can run on 24v, but the weird thing is I can't even find the motor specifications on the cyclone site, but they list it for every other motor they have.
 
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