diff --git a/src/BLDCMotor.h b/src/BLDCMotor.h
index a1f196ab..a7155c1f 100644
--- a/src/BLDCMotor.h
+++ b/src/BLDCMotor.h
@@ -69,8 +69,7 @@ class BLDCMotor: public FOCMotor
     void move(float target = NOT_SET) override;
     
     float Ua, Ub, Uc;//!< Current phase voltages Ua,Ub and Uc set to motor
-    float	Ualpha, Ubeta; //!< Phase voltages U alpha and U beta used for inverse Park and Clarke transform
-
+    
   /**
     * Method using FOC to set Uq to the motor at the optimal angle
     * Heart of the FOC algorithm
diff --git a/src/StepperMotor.h b/src/StepperMotor.h
index 7eda3167..45d20c63 100644
--- a/src/StepperMotor.h
+++ b/src/StepperMotor.h
@@ -73,8 +73,6 @@ class StepperMotor: public FOCMotor
      */
     void move(float target = NOT_SET) override;
     
-    float	Ualpha,Ubeta; //!< Phase voltages U alpha and U beta used for inverse Park and Clarke transform
-
   /**
     * Method using FOC to set Uq to the motor at the optimal angle
     * Heart of the FOC algorithm
diff --git a/src/common/base_classes/FOCMotor.cpp b/src/common/base_classes/FOCMotor.cpp
index e0a00887..5d8f8127 100644
--- a/src/common/base_classes/FOCMotor.cpp
+++ b/src/common/base_classes/FOCMotor.cpp
@@ -32,6 +32,10 @@ FOCMotor::FOCMotor()
 
   // voltage bemf 
   voltage_bemf = 0;
+
+  // Initialize phase voltages U alpha and U beta used for inverse Park and Clarke transform
+  Ualpha = 0;
+  Ubeta = 0;
   
   //monitor_port 
   monitor_port = nullptr;
diff --git a/src/common/base_classes/FOCMotor.h b/src/common/base_classes/FOCMotor.h
index b5b0a557..b5ba2e96 100644
--- a/src/common/base_classes/FOCMotor.h
+++ b/src/common/base_classes/FOCMotor.h
@@ -161,6 +161,8 @@ class FOCMotor
     DQVoltage_s voltage;//!< current d and q voltage set to the motor
     DQCurrent_s current;//!< current d and q current measured
     float voltage_bemf; //!< estimated backemf voltage (if provided KV constant)
+    float	Ualpha, Ubeta; //!< Phase voltages U alpha and U beta used for inverse Park and Clarke transform
+
 
     // motor configuration parameters
     float voltage_sensor_align;//!< sensor and motor align voltage parameter