Synchronous Motor

The field winding of a synchronous motor is on the...

• Stator

• Rotor

The armature winding is supplied with...

• DC voltage

• Single-phase AC voltage

• Three-phase AC voltages

Which of the following are possible types of rotor in a synchronous motor?

• Cylindrical rotor

• Squirrel cage rotor

• Salient pole rotor

Which winding produced the rotating magnetic field in the synchronous motor?

• Field winding

• Armature winding

• Compensating winding

Which formula is used to calculate the synchronous motor speed in rpm?

•  $\frac{120P}{f}$  

•  $\frac{120f}{P}$  

For the armature circuit of the synchronous motor, which equation is correct? 

Hint: Look at the equations correctly!

•  $V_{\phi}=E_A+I_A\left(R_A+jX_S\right)$  

•  $V_{\phi}=E_A-I_A\left(R_A+jX_S\right)$  

If field current is kept constant, which of the statements below is correct?

• $\delta$ stays constant

• $\left|E_A\right|$ stays constant

• $f$ stays constant

Which of the following is the torque-speed curve for a synchronous motor?

Hint: Pay attention to the axes!

• 
• 
• 

What does lagging power factor (PF) mean in the synchronous motor?

• $I_F$ lags $V_F$

• $V_{\phi}$ lags $I_A$

• $I_F$ lags $V_{\phi}$

• $I_A$ lags $V_{\phi}$

 The angle $\delta$ in a synchronous motor is always..

• positive

• negative