EM 1-121

37 - The control of a trapezoidal brushless is based on:

• An open loop stator control

• A scalar control

• A vector control using dq axis reference frame

38 - In DC motor in steady state conditions, the absorbed current depends on:

• The motor typology

• The voltage supply

• The load torque

39 - What is the right equation of the reactive power produced by a synchronous generator:

40 - What is the starting torque equation of an induction motor in steady state conditions?

41 - What are the right electrical equations of synchronous machines in transient conditions?

42 - In a PWM inverter the DC bus voltage is:

• Variable with the output frequency

• Depending on the induction motor load

• Constant with the output frequency

43 - What is the torque equation of an induction motor in transient conditions?

44 - What is the equation of a DC motor in transient condition?

45 - In order to connect a synchronous generator to the main system, it is necessary to have the following conditions:

• Same voltage values, synchronous reactance equal to the impedance of the line, voltage of the generator orthogonal with the voltage of the main

• Excitation current equal to zero, same frequency values, voltages of the generator in phase with voltages of the main

• Same voltage value, same frequency values, voltage of the generator in phase with voltages of the main

46 - What is the right equation of a rotating magnetic field produced by a three phase system: