# motor how to think about sizing



## boyaka (Oct 10, 2009)

so from what i read so far motors are rated at there continuous rating and are really only limited by heat and voltage (because of arcing) and it sounds like you can go up to like ten times the rated power for very short periods of time for like accelerating and use around or less then contiuos rating to keep speed up.
so if i had a truck that had a 150 horse power and i wanted to covert it to electric with keeping the power near the same i would be looking for a motor around 30 to 50 hp so a warp 11 is at 44 hp so it would be a bigger motor for a truck . also it seems to me i want to if i can drop rpm compared to a gas motor by 3/4 to a 1/2. just want to make sure i have the right thought process going before I even think about getting a anything 
thanks for taking a look at this post i am sure you have seen many post like this one just need to put it in my words to understand it.


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## PStechPaul (May 1, 2012)

The continuous power you need is mostly determined by the vehicle characteristics, especially weight, and both the speed and acceleration (or road slope/grade). A small car might need 15 HP just to stay at 60 MPH on a flat or 2% grade road while a truck is probably twice that. Bigger is better, up to a point where weight and size become significant, but motors are much more efficient when used at or below their ratings. Try this to figure out what to expect:
http://enginuitysystems.com/EVCalculator.htm

Hope this helps.


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