Please select the right statement of DC machine for DC machi

Please select the right statement of DC machine for DC machine from the following The current following through each of the armature conductors is not DC current DC motor speed cannot be controlled by applied armature voltage DC motor\'s speed is directly proportional to its poles number The electromagnetic held in DC machine is a rotating magnetic field Please select the right statement about the speed control of the permanent magnet DC motor with a constant load torque the speed cannot be controlled by the applied armature voltage the speed can be reduced by decreasing the applied armature voltage the speed can be increased by increasing the armature resistance (to connect external resistors with the armature windings in series) none of above Figure 2 shows a specific operational mode of a permanent magnet DC motor. A DC voltage is applied to the armature through brushes and commutator, straight phi_f indicates the direction of the magnetic field: omega_m indicate the rotor rotating direction: the\"cross\" sign means i_a flows into the page while the \"dot\" sign means i_a flows out from the page. Which operational mode is this motor in? By default, anticlockwise is the forward ?(or positive) direction motoring in forward direction motoring in backward direction regenerative braking in forward direction regenerative braking in backward direction

Solution

6)A

7)B

8) electro magnetic torque opposit to motor torque

so option C