A Simpler Explanation Of The Measurement Of ONE HORSE POWER
One horsepower equals 550 foot pounds (pound feet) per second. In high school, in physics class, I generated 1 horsepower by running up a flight of stairs. :) Housted
Forum Discussion
valhalla360 wrote:
I did a little checking and it looks like they limit torque at higher RPM to control thermal problems. The motor could keep up the torque but it would lower life expectancy. So the drop off after 6000 rpm is electronically applied. They could have added better cooling and kept the torque up...but the car is already overpowered.
A couple of notes:
- At zero RPM, it by definition, you don't have 2hp.
- The graph is misleading as they are comparing it to a drastically less powerful gas engine. I'm guessing they used a turbo engine as most torque curves are much more rounded and will result in a wider power HP band (they left the HP off the chart...presumably to help with the misleading).
Of course they limit power otherwise it would pull too much current and things start melting and catching fire. Its not that the motor won't try, it will accept the power as any hunk of metal would.
Yes zero rpm is 0 hp, but an electric motor has usable hp from 1 to your gas engines stall speed. A 3/4 hp pump motor might have a 4hp peak as it pulls large amounts of current during startup from 0 to operating rpm. It cannot sustain that peak without damage, so its operating or rated hp is much lower.
The point with the graph is the rpm range, a more powerful gas engine still does not have a larger rpm range, just more torque and power in that narrow rpm range. Again the electric motor produces a relatively flat power curve over an rpm range that entirely encompass a gas engines operating range. It doesn't come in until 6000 rpm the redline of many gas engines, so they just gear it down without the need for gear shifting.
