I have a brushless Motor then i am using in conjunction with a ESC, powered by a Lithium Polymer Battery(3S 1300mah). I just got a new Lithium Polymer battery (6S 15000mah) from a friend and am planning on using it to power my motor.
From the motor details shown by the manufacturer here:- http://www.emaxmodel.com/views.asp?hw_id=15 , it shows the motor being rated at 3S 17A MAX. If i were to calculate it's wattage, it would be (4.2 * 3) * 17 = 219.3W, assuming a voltage of 4.2V per LiPo Cell. However, as 17A is the max rated current, and that the max continuous current is not given, i would be using 15A as an estimate, which would give me a wattage of 189 Watts.
While the motor is shown to be using 3S LiPo batteries, would i be able to power it with a 6S LiPo Battery with a lower current draw?( I'm assuming that the motor will draw less current since more voltage is supplied to it).
Am I right in thinking that i should be able to power the motor with a variety of voltages, as long as the power(voltage * current) does not exceed the max rated wattage of the motor?
If so, given an extreme example, would i be able to power the motor at 100V @ 1.89A(not that it would be feasible or would i ever do it), or is there a max limit to the voltage and/or a min limit to what the current supplied must be for the motor to work?
All thoughts, opinions and answers would be greatly appreciated.
Best Answer
Power limit for the motor is 204 watts - that's stated in the improved link.
Also note that the speed of the motor is dependent on voltage (\$K_V\$) and that is 1270 rpm per volt applied. The more applied voltage the faster it spins and, for a fixed mechanical load, the power will increase proportionally with RPM squared. So, for a given mechanical load, power quadruples for a doubling of voltage.
This cannot be avoided because the motor spins faster with more voltage applied. Output power is \$2\pi n T\$ where n is revs per second and T is torque to the load and for a fixed mechanical load, a doubling in n also means a doubling in T hence power output to the load quadruples with a doubling of voltage.
At 100 volts applied (with only a light mechanical load), the speed of the shaft would be 127,000 RPM and the motor will shake to bits well before that point.