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How are motors driven. 3 wire = 3 phase?

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“Kv” refers to the constant velocity of a motor (not to be confused with “kV,” the abbreviation for kilovolt). It is measured by the number of revolutions per minute (rpm) that a motor turns when 1V (one volt) is applied with no load attached to that motor. The Kv rating of a brushless motor is the ratio of the motor’s unloaded rpm to the peak voltage on the wires connected to the coils.

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So-called three phase direct current brushless motors are really just three pole stepper motors and the esc’s are stepper drives while the flight controller/radio transmitter combination is a pulse generator/wireless pendant.

Motors are controlled by pulse width modulation, hence the three wires. Half throttle means that the motor is getting full voltage half the time. So for instance let’s say in three seconds, the flight controller sends 300 pulses to the motor. Since we’re at half throttle, 150 of those pulses will be full voltage, and 150 of those pulses will be 0 voltage. The pulses happen so fast that the motor takes an average voltage.

an 1800kv motor at 5.5 volts will spin at 1800*5.5 which equals 9900 rpm no load. Because as stated, the kv is rpm per volt.

more voltage = more current = more magnetic flux from coil = more speed for a fixed number of turns and fixed magnetic properties.
The current and the number of coil turns in the windings determine a motor’s maximum torque output, while the voltage applied to the motor and the inductance of its windings will affect the speed at which a given amount of torque can be generated
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