Ensure the Drive Is Adequate

The first question you need to ask is, is your efficiency really bad For example, if you have a worldwide input Flyback of around TOW, you should not be expecting much better than 70% at an input of 90VAC (for the common 5 V/12V output rail combinations). For a Synchronous Buck converter, you can expect around 90% at max load, but at very light loads the efficiency will fall much lower. So first assure yourself you really have a problem. And don t forget that this measurement needs Kelvin sensing as described previously (see Chapter 2). 

where could the problem lie Is it within the power supply stage itself, or is it external If you have peeled the onion as I suggested previously, you are hopefully sure the efficiency is not being lost within the EMI filter of your AC-DC power supply. Bypass or disconnect everything external and confirm you have a problem. 

The next question is, is the efficiency being lost in the switch If so, there could be many reasons for that. A switch could be lossy simply because its drive is inadequate. Early self-oscillating converters (ringing choke oscillators) were extremely lossy because the drive would slowly droop to the point where it just couldn t sustain itself and then the switch would turn OFF. Modem self-oscillating converters have improved tremendously on this, and you can even find full-fledged multi-output PC power supplies that don t have a single 

As you can see, we started off with a discussion on efficiency, but ended up touching noise and efficiency issues. Isn t that typical of power supply design  

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Valve, Explosive Calculations. In the past, explosively actuated valves have been designed on an empirical basis because the interactions and forces involved in a valve operation were not fully understood. However, this design approach was satisfactory in that the size and design of the valves permitted a more than adequate amount of expl to be used to ensure proper operation of the valves. That is, the driving force available from the extra expl pro-... 

A first round of the systematic review of the reactor operating eiqierience has been completed for the absorber rod drive mechanisms, main sodium pumps and intermediate heat exchangers (IHXs) which has revealed sensitive points for EFR. Examples are the importance of succeeding with the EFR features which prevent die sodium aerosol problems on the absorber mechanisms, the need to confirm adequate operational flexibility whilst avoiding the check valve at the primary pump outlet and to ensure full benefit is taken of the piston seal experience for the IHX / pool boundary replacing the gas bell originally selected for EFR. 

Management commitment filters down from the top leadership through all levels of the organization. For our discussion, we will be using the term leadership team in order to incorporate all levels of management and supervision. The leadership team commitment is considered the driving force found in all successful safety management systems. The leadership team provides the vision/mission and direction as well as adequate resources to ensure... 

The drive ratio is the speed of the faster shaft divided by the speed of the slower shaft. The drive ratio normally should not be more than 6 1 in a single-stage drive. Larger drive ratios may be used with careful design and very good maintenance, but a two-stage drive is usually better. Check high-ratio drives carefully to ensure there is adequate wrap on the small sprocket. 

When the main frame adequately fulfils its function, a sub-frame is not used. The sub-frame forms a base for the main frame carrying the rotating assembly plus the main drive motor and back-drive system when used. It ensures that there is no unwanted differential movement with either of the drives and the rotating assembly. Vibration isolators are strategically placed under the sub-frame to share the load properly The use of a sub-frame subjects the drive motor to more vibration, but at the same time it makes installation easier. 

Key application points must be defined in order to properly apply an induction motor to a solid-state adjustable-firequency controller torque, speed range, motor description, and environment. In order to ensure that adequate torque is available to drive the load and adequate current is available to produce the required torque, the starting torque, the peak running torque, and the continuous torque requirements must be defined. The continuous torque is usually defined, but the peak and starting torques are more difficult to define. For the case of retrofit applications, the speed-torque curve of the existing motor mig t be used as... 

The choice between Al-Zn-In and Al-Zn-Hg may well be influenced by their respective operating potentials and capacities. Where an additional driving voltage is required (such as in seabed mud), Al-Zn-In anodes may be preferred to ensure adequate structure polarisation. Alternatively, a lower driving potential may be acceptable where the additional capacity (and hence weight saving) is the predominant factor this favours Al-Zn-Hg anodes. 

In a small number of patients whose respiratory center is depressed by long-term retention of carbon dioxide, injury, or drugs, ventilation is maintained largely by stimulation of carotid and aortic chemoreceptors, commonly referred to as the hypoxic drive. The provision of too much oxygen can depress this drive, resulting in respiratory acidosis. In these cases, supplemental oxygen should be titrated carefully to ensure adequate arterial saturation. If hypoventilation results, then mechanical ventilatory support with or without tracheal intubation should be provided. 

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