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Old May 07, 2010, 04:13 PM
TouroLouco is offline
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Mozambique
Joined Nov 2009
32 Posts
Quote:
Originally Posted by NoFlyZone View Post
Hi Touro,

Many times, motors that we buy aren't rated by the manufacturer for their constant current rating. All motors really should have these specs published, but they aren't. So what do we do? Easy! We apply a little rule of thumb to help us along the way. This will allow us to get a good approximation of the constant current rating of motors that are sold cheaply on places like HobbyKing.

Multiply the weight of the motor by 2-3 to find a safe power level in watts for the motor.

Looking at the 60 gram 750 kV motor you linked to:
60 x 2 = 120 watts This is the power level we can run it at all day without overheating it. Our constant current rating, if you will.

60 x 3 = 180 watts This is the power level we can run it at for short periods of time only. Our burst current rating, if you will.

Since the average voltage of a 3s Li-Po over the course of a flight is about 10.8 volts, we can take 120 watts and divide it by 10.8 volts and the answer is about 11 amps. We can safely say that this motor then, has a constant current rating of about 11 amps. So can we use it if we wanted a constant current rating of 12 amps? Heck yes, because 11 is pretty darn close to 12, and our rule of thumb we used has a nice safe margin of error built into it.

Does this help?
This definately helps... Thank you very much. Its been great reading through the information you have posted.
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