apply fix to stepper motor logic as well

Author: nmscode

src/StepperMotor.cpp

@@ -16,7 +16,7 @@ StepperMotor::StepperMotor(int pp, float _R, float _KV, float _inductance)
   phase_resistance = _R;
   // save back emf constant KV = 1/K_bemf
   // usually used rms
-  KV_rating = _KV*_SQRT2;
+  KV_rating = _KV;
   // save phase inductance
   phase_inductance = _inductance;
 
@@ -292,7 +292,7 @@ void StepperMotor::move(float new_target) {
   if(_isset(new_target) ) target = new_target;
 
   // calculate the back-emf voltage if KV_rating available U_bemf = vel*(1/KV)
-  if (_isset(KV_rating)) voltage_bemf = shaft_velocity/KV_rating/_RPM_TO_RADS;
+  if (_isset(KV_rating)) voltage_bemf = shaft_velocity/(KV_rating*_SQRT3)/_RPM_TO_RADS;
   // estimate the motor current if phase reistance available and current_sense not available
   if(!current_sense && _isset(phase_resistance)) current.q = (voltage.q - voltage_bemf)/phase_resistance;