theaveng
Well-known member
When does the motor reach 3000rpm?
At what RPM is the motor most efficient?
At what RPM is the motor most efficient?
I thought I read elsewhere that the motor was limited to only 6000 rpm? That means it could never reach 60mph (by your calculation). Maybe I misunderstood about the rev limit.garygid said:Thus, at 6800 rpm one is going 1 mile per minute, or 60 mph, approximately.
So, 3000 rpm would be about 26 mph.
theaveng said:I thought I read elsewhere that the motor was limited to only 6000 rpm? That means it could never reach 60mph (by your calculation). Maybe I misunderstood about the rev limit.garygid said:Thus, at 6800 rpm one is going 1 mile per minute, or 60 mph, approximately.
So, 3000 rpm would be about 26 mph.
theaveng said:So the motor spins 10,600 rpm at the max speed of 94? Wow. I hope it's well built.
So when I rent my Leaf, 26 mph will put me at the motor's torque peak. Good to know. I was impressed with how fast the thing accelerated during my testdrive. (Contrary to some poster's bosses' opinion, the acceleration is good.)
It's a synchronous AC motor. The power control unit adjusts the relative angle between the "active" winding and the magnet to achieve maximum torque at ~3000 RPM. The torque curve is then essentially flat from 3000 to max RPM (10,200). You could change the programming in the control unit to have maximum torque at 0 RPM, but my understanding is that Nissan wanted the Leaf to feel more like a "normal" car.theaveng said:Now I'm really confused. In another topic a person stated the max torque was at 3000rpm. He wanted to add a 2nd gear in order to "adjust" the motor speed from 7000 to 3000 at highway speeds.
Oh I had read the torque curve drops off. This is why I want to buy a Leaf (or Volt), because as an electrical engineer the technology fascinates me. Unfortuantely I cannot afford the $30,000 pricetag; I'll buy used for ~15,000.sproqitman said:The power control unit adjusts the relative angle between the "active" winding and the magnet to achieve maximum torque at ~3000 RPM. The torque curve is then essentially flat from 3000 to max RPM (10,200).
You have it backwards. Most EVs have flat torque from 0 RPM to somewhere around 3000-4000 RPM (peak torque is limited by peak current across the motor windings). Above 3000-4000 RPM torque falls off but power remains at it's peak (typically limited by battery current) until you approach top speed when motor efficiency really starts dropping off.sproqitman said:It's a synchronous AC motor. The power control unit adjusts the relative angle between the "active" winding and the magnet to achieve maximum torque at ~3000 RPM. The torque curve is then essentially flat from 3000 to max RPM (10,200). You could change the programming in the control unit to have maximum torque at 0 RPM, but my understanding is that Nissan wanted the Leaf to feel more like a "normal" car.
Don't ask me to follow up. That's the limit of my knowledge of AC motors ;-)
drees said:Above 3000-4000 RPM torque falls off but power remains at it's peak (typically limited by battery current) until you approach top speed when motor efficiency really starts dropping off.
theaveng said:So the motor spins 10,600 rpm at the max speed of 94? Wow. I hope it's well built.
So when I rent my Leaf, 26 mph will put me at the motor's torque peak. Good to know. I was impressed with how fast the thing accelerated during my testdrive. (Contrary to some poster's bosses' opinion, the acceleration is good.)
Yes, I do have it backwards. I was mis-remembering this thread http://www.mynissanleaf.com/viewtopic.php?f=27&t=5323, and swapped torque for power.drees said:You have it backwards. Most EVs have flat torque from 0 RPM to somewhere around 3000-4000 RPM (peak torque is limited by peak current across the motor windings). Above 3000-4000 RPM torque falls off but power remains at it's peak (typically limited by battery current) until you approach top speed when motor efficiency really starts dropping off.sproqitman said:It's a synchronous AC motor. The power control unit adjusts the relative angle between the "active" winding and the magnet to achieve maximum torque at ~3000 RPM. The torque curve is then essentially flat from 3000 to max RPM (10,200). You could change the programming in the control unit to have maximum torque at 0 RPM, but my understanding is that Nissan wanted the Leaf to feel more like a "normal" car.
Don't ask me to follow up. That's the limit of my knowledge of AC motors ;-)
Yeah I know motors are simpler, cheaper, etc but you still have to hold the thing together at high speeds. Ever heard of the CDs that disintegrate because they were spun too fast?BraveLittleToaster said:Yeah, electric motors routinely spin to well over 10,000 RPM. A Dremel for example, can get around 13,000 RPM. It's because they're far easier to balance than an ICE is, and just as importantly, they're astoundingly simple. There's only one moving part.
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