Separately excited

For field-oriented controls, a mathematical model of the machine is developed in terms of rotating field to represent its operating parameters such as /V 4, 7, and 0 and all parameters that can inlluence the performance of the machine. The actual operating quantities arc then computed in terms of rotating field and corrected to the required level through open- or closed-loop control schemes to achieve very precise speed control. To make the model similar to that lor a d.c. machine, equation (6.2) is further resolved into two components, one direct axis and the other quadrature axis, as di.sciis.sed later. Now it is possible to monitor and vary these components individually, as with a d.c. machine. With this phasor control we can now achieve a high dynamic performance and accuracy of speed control in an a.c. machine, similar to a separately excited d.c. machine. A d.c. machine provides extremely accurate speed control due to the independent controls of its field and armature currents. 

With the availability of phasor control technology, by which one can separate out the active and magnetizing components of the motor s stator current and vary them individually, it is now possible to achieve higher dynamic performance and accuracy of speed control in an a.c. machine similar to and even better than a separately excited d.c. machine. 

Direct-current motors are classified as separately excited motors, series motors, shunt motors, and compound motors. The field winding of a separately excited motor is in a circuit that is energized by a separate dc source the field winding is not physically connected to the armature circuit (containing the armature winding). 

Herman Lemp Separately excited DC generator longer in Mexico. 

Mixture Generation Separation Excitation Fragmentation Separation of of (into the of... 

If the relaxation rate is plotted (Fig. 2) at the blue absorption band at 460 nm the lifetime is approximately 21 psec. However, the lifetime of the bleaching at 570 nm is 46 psec. These relaxation times differ enough to make it highly probable that two separate excited states are being seen. Thus an excited state absorption decays (21 psec) before reappearance of the ground state (46 psec). 

Case 3 Compressed tetragonal bipyramid, large Aax X - the ground orbital singlet 3A2g is well separated, excitations calculated within the 3Tig and 3r2g patterns. gz = ge... 

Indicates a charge-separated excited stale Indicates an electronically excited state... 

Unfortunately, the result shown in Figure 2 corresponds to time-shared (i.e., essentially simultaneous) excitation/detectlon, so that the (discrete) frequencies sampled by the detector are the same as those initially specified in synthesis of the time-domain transmitter signal. However, FT/ICR is more easily conducted with temporally separated excitation and detection periods. In practical terms, the result is that for FT/ICR, we need to know the excitation magnitude spectrum at all frequencies, not just those (equally-spaced) discrete frequencies that defined the desired excitation spectrum. 

Another strategy is to utilize single multiband dichroic mirrors and emission filters and separate exciter filters either in an external slider or filter wheel. This will preserve the image registration and reduce mechanical vibrations, but the trade offs are a reduced brightness of the fluorescence, limitations on how many different probes can be separated, and reduced dynamic range and sensitivity due to the necessary color CCD camera. 

Colocalization can only be ascertained in the absence of cross-talk between or bleed-through from selected fluorochromes. Accurate colocalization can only occur, if emission spectra are sufficiently separated between fluorochromes and, if correct filter sets are used during the acquisition step. Choosing fluorochromes with well-separated excitation and emission spectra is, therefore, critical for multiple labeling (multiple fluorochromes) and colocalization (15, 16). In addition, it is important to consider the microscope setup because... 

Four schematic situations are shown in Figure 1. In (a), the exciplex state is at a much higher energy than the LE state at all intermolecular separations excitation of the LE state cannot lead to electron transfer. It is noted that solvation may considerably reduce the energy of the exciplex state, so that the two energy curves may... 

In separately excited DC machines (Fig. 5.3d) the excitation is obtained by means of field windings which have a supply separated from the rotor windings, and this gives a separated control of speed and torque, according to what is required in an electric vehicle. Separately excited brushed DC motors were widely... 

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