Electromechanical drives

Fig.5. Appearance of installation for the testing of pistons of diesel engines. 1- ultrasonic flow detector 2- electronic blocks 3- electromechanical drives 4- immersion bath 5-controllable detail.

The TA Instruments CSL2 rheometer can perform low frequency oscillatory measurements as well as steady-state viscosity determinations, even though it has a simple mechanical system. The sinusoidal wave form is generated mathematically in the computer rather than with an electromechanical drive system. The stress is controlled, and the resulting strain is determined and stored in memory. The computer analyzes the wave form and calculates the viscosity and elasticity of the specimen at the frequency of the test. As of this writing (1996), the oscillation software covers a frequency range of 10-4 -40 Hz. This range could be increased as faster software and computers become available. 

The prevalent design is a microprocessor-controlled torque rheometer. The system consists of two basic units an electromechanical drive unit and a microprocessor unit. The basic system is shown in Figure 7. 

The Mftssbauer effect experiments were performed using a /Co/Rh source and a conventional electromechanical drive. Data were collected between 297 and 4.2 K on a Nuclear Data ND 6600 computer and were analyzed by least squares fitting of the appropriate line shapes to the spectra describing the hyperflne Interactions. The amount of Fe In the chabazlte was about 1 wt. % Absorption path lengths were optimized In sample preparation by uniformly distributing 200 mg/cm2 of the chabazlte. 

Fig. 2.2 (a), (b), and (c) show three of the most popular voltage waveforms for electromechanical drive systems, (d) illustrates how each detected y-ray can be used to produce a pulse with amplitude characteristic of the instantaneous velocity. 

Note the fuel cell plot refers to fuel cell plus balance-of-plant, whereas the fuel cell drive-train plot also includes the electromechanical drive to the wheels. 

The normal experimental technique is to scan rapidly through the velocity range and repeat this scan many times imtil data of the required accuracy has been accumulated. The Doppler motion is provided by an electromechanical drive system controlled by a servo -amplifier. Usually, the source is attached to the drive shaft and driven either in a saw-tooth or a triangular constant acceleration wave form. The transducer is coupled to a multichannel analyser operating in the multiscaler mode, and the servo-amplifier is controlled by the channel advance frequency. The dwell time in each channel, corresponding to a specific velocity increment, is 100 ps, and while the channel gate is open it accepts pulses from the detector. 

FIGURE 8.4 Electromechanically driving actuators based on a novel electromagnetic mechanism. Schematic illustration to the helical assembly of CNTs into helically primary and secondary fibers withcxit any guest materials. 

Pritschow G (1998) A comparison of linear and conventional electromechanical drives. Ann CIRP 47(2) 541-547... 

Developments in web tension control systems are providing increased capability and function to eliminate problems (Fig. 3-34). They include ultrasonic roll diameter sensors, pneumatic pressure gauge tension monitors, capston-Mt. Hope tension systems, and so on. As an example, replacement of a web-tensioning system s conventional electromechanical drive with an ordinary ac motor enables processors to lower system cost and improve web consistency, as has been done for many years. A vector control system uses a belt and pulley arrangement to remotely couple an encoder to the shaft of the ac induction motor. This approach provides closed-loop feedback, without requiring that one modify the relatively inexpensive motor by installing a special feedback device on it. 

The rotational actuation, which is typically provided by a conventional, low-cost spindle motor, also removes the requirement of external, pressure-driven pumps and their associated microfluidic interconnects and chip-to-world interfacing. Moreover, the modular nature of the LoaD platform completely separates the electromechanical driving instrumentation and the conventional optical readout units from the liquid sample and reagents under test the sample and/or reagents are exclusively handled by the microstructured, typically disposable test disc. These features are particularly beneficial for biological applications since the potentially hazardous samples can be processed in an encapsulated system, thus minimizing the risk of crosscontamination and carry-over. 

Insertion of the absorber rods into the core, by the electromechanical drives ... 

Servomechanisms are devices used to control motion. Two basic types involve hydraulic or electromechanical drives. The latter t) es involve stepping motors or DC variable speed motors. A stepping motor receives controlled pulses of energy that cause stepwise rotation in response to each pulse. 

---