Voltage variation

Voltage unbalance System harmonics Voltage variation Frequency variation Ambient temperature and Altitude. 

Note IS 325 specifies voltage variation 6% and frequency variation 3% or any comhination of these. 

Voltage variation may influence the motor s performance as shown below. 

Motors aro designed to develop rated output at 95% voltage Figure 1.9 Effect of voltage variation on the motor output... 

Table 24.3 Permissible voltage variations during temporary system disturbances...

At unity p.f. the voltage variation and hence the regulation is the least and maintains a near-flat voltage profile. This is the best condition to provide the highest level of system stability from a voltage point of view. 

By altering the dieleetric mix and its thickness it is possible to change the characteristics of an element to make it suitable for higher voltage variations and non-linear loads. 

Systems prone to frequent voltage variations Capacitor elements are non-self-healing and are generally provided with internal fuses An inductor coil may not be necessary with such capacitors... 

If voltage variation is also to be considered, then one may have to choose the next higher size. As in Table 30.8, one can choose an extra-heavy pipe of 5" size. 

Obviously, it is not very easy to measure voltage variations inside a piece of iron, but we can artificially transport the oxygen-reduction reaction away from the metal by using a piece of metal that does not normally undergo wet oxidation (e.g. platinum) and which serves merely as a cathode for the oxygen-reduction reaction. 

Table 7 -4-l-3b Minimum Ignition Voltage Variation with Capacitance and Electrode Diameter... 

Apart from considerations given to corrosion resistance and suitability for hazardous (classified) areas, the selection of electric motors for oil field applications is the same as the selection of electric motors for other industrial applications. One exception may be the selection of motors for areas where electric power is self-generated. Frequency and voltage variations may occasionally occur at such locations. For such locations, consideration should be given to specifying motors which are tolerant to at least 10% voltage variations and 5% frequency variations. 

Another important hut little-known piezoelectric effect is found in some electronic systems. Speaking produces pressure variations that propagate through the air. Forces are produced on anything in contact with this vibrating air so that when contact is with a piezoelectric crystal, tiny voltage variations are produced. A ci ystal microphone is designed to make use of this piezoelectric effect. 

Steady-state voltage regulation Acceptable transitent voltage variation Non-linearity characteristics of load current Percentage distortion in voltage Frequency tolerance Power factor of load Inmsh upon switch-on... 

Through measurement of the lateral-voltage variation of the position detectors, the torsional angle Oj of the cantilever can be given by... 

TABLE 2 Voltage Variation Factor /S as a Function of Tension (a) for the Uniform Membrane, and with Undulation Included in both Local (L) and Nonlocal (NL) Approximations, for Soft/ Rigid Membranes in the Metallic Approximation, Eq. (66)... 

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