Protection types

Fig. 4. Comparison of the three types of tetracycline resistance where T represents the tetracycline molecule O, a tetracycline transporter and aaa/, the ribosome A shows the effect of tetracycline exposure on a sensitive cell B, the efflux of resistance where a cytoplasmic membrane protein ( D) pumps tetracycline out of the cell as fast as the tetracycline transporter takes it up C, the ribosomal protection type of resistance where the ribosome is modified by ( ) to block productive binding and D, the tetracycline modification type of resistance where t is an inactive form of tetracycline. Reproduced with...

Type I A weather-protected Type I machine is an open machine with its ventilating passages so constructed as to minimize the entrance of rain, snow and air-borne panicles to the electrieal parts and having its ventilated openings so constructed as to prevent the passage of a cylindi ical rod 3/4-inch in diameter. 

Protected-type motors, located in dusty environments, should be blown out periodically with clean and dry air. Replace the motor, if possible. 

Failure may be caused by coal dust, fly ash and moisture. Pollution may weaken the insulation, particularly of a protected type motor and result in a failure at some stage. 

The bus system of a switchgear assembly, its interconnecting links and wires are the protected type components, whereas an interrupter (breaker, switch or a fuse) may be a protecting or protected type, depending upon their application and location in the circuit. A contactor and an OCR are therefore protected devices in the same context, for they provide no short-time protection. A protecting device may become protected when it is also provided with a back-up protection. 

For larger motors, the next degree of protection is weather-protected, Type I (WPI), which is an open machine with ventilating passages con-stnicted to minimize the entrance of rain, snow, and airborne particles (o the electric parts. 

Weather-protected, Type II (WP-II), 259 Weight flow control at con,stant speed, 362 Weight flow control with variable stator vanes, 361... 

A weather-protected Type II machine shall have, in addition to the enclosure defined for a weather-protected Type I machine, its ventilating passages at both intake and discharge so arranged that high-velocity air and air-borne particles blown into the machine by... 

Motor enclosures for outdoor use are NEMA weather-protected Type II, totally enclosed, fan-cooled, or drip-proof with weather protection. Motors of the latter type are widely used. Not only are they less expensive than the other types, but they also have a service factor of 1,15. The above enclosure types are all suitable for the Class I, Group D, Division 2 classifications usually encountered. 

FULL LOAD TORQUE MOTOR PROTECTION TYPE 40... 

Malay ethnie nationalism, of the protective type analysed in chapter 2, had had an exceptionally long innings in Malaysia. In its UMNO form it had, however, been unable to expand its agenda to become an inclusive type of state nationalism of civic kind. By 2008 there were claims that this was a kind of failed nation (Sani 2008). On the other hand, the sense of threat that had given rise to this brand of ethnie nationalism in the 1940s, when there were very few Malays in the modern economy, was unconvincing to a new generation who had seen the Malay population increase to some 60 per cent of the... 

They involve numerous outcome events (e.g., all sorts of adverse events, laboratory tests, ECG tests). This means that considerable attention must be paid to issues of multiplicity (see Section 7.10), making it important to protect Type I error. A significant result is therefore difficult to interpret. 

Enclosed motors with air-to-water coolers cost much less than TEFC motors above 373 kW (500 hp) in large synchronous-motor ratings, they cost even less than weather-protected, type II. Large enclosed synchronous machines with coolers for mounting in the motor foundation are frequently supplied at lower cost than motors with integral-mounted coolers. 

For all these reasons an increase in chromium concentration may be the best solution to increase the sulphidation resistance of iron-aluminium alloys. The present work has shown that chromium has a very beneficial effect on the sulphidation resistance in oxygen deficient gases. Such improvement of sulphidation resistance in H2S environments has also been found in nickel-aluminium alloys, where the corrosion rate decreased significantly, when 8 wt% chromium were added [22], Whether chromium increases the rate of alumina formation or contributes to the formation of protective spinell type oxides Fe(Cr,Al)203 cannot be decided from the available results. It is also possible that chromium catalyses the transition from a less to a more protective type of A1203. It was for example found that chromium enhances the transition from 0-Al2O3 to a-Al203 in Ni-Al at temperatures above 1000°C [30],... 

The oxidation behaviour of TiAl at 900°C and 1000°C (Figs. 2 and 3) was characterised by increasing attack with increasing temperature, as expected by protective type kinetics (rate decreasing with increasing time) initially but then after 50h at 900 C and 30 h at 1000°C, coincident with the onset of substantial scale spallation, by an increasing oxidation rate. The kinetics of cumulative spallation were similar to those of oxidation. As at 800°C the extent of oxidation of FeCrAlY coated TiAl at both... 

Composites for military and aerospace uses The preparation and properties of composites using aromatic polyamide-hydrazide fibres have been described/ and one area in which the X-500 fibres have clearly been tested as composite reinforcements outside Monsanto is that of personnel armour for ballistic protection. Type 3 seems to have given the most promising results, the stiffer types tending to fail by longitudinal splitting. ... 

The basic idea of the ignition protection type control of ignition sources" is to monitor potential sources of ignition in such a way that they can be eliminated before they become effective. Parameters such as temperature, level, revolutions, vibrations are monitored. It is essential for this type of protection and hence for this category that the monitoring equipment is highly reliable. 

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