Sulfur Hexafluoride Gas (SF6) Properties
Sulfur Hexafluoride Gas (SF6) Properties Heavy, chemically inert, non toxic No poisonous effect on the human body but decomposition products are poisonous Color less and odor less It is gaseous at normal room…
DC machines and Induction Machines Viva Questions & Answers
When DC Generator fails to build up the voltage, what are the reasons? No residual magnetism, reversal of field connections and the resistance in the load circuit may be greater…
Advantages and Disadvantages of Per Unit System
In power system analysis, per unit (pu) system is used to express a physical variable as a fraction of base or reference value. Per Unit (pu) is commonly used for…
Why Symmetrical Components Used for Unbalanced faults in Power System
Symmetrical Components: Any unbalanced three phase system of currents, voltages or other sinusoidal quantities can be resolved in to three balanced of phasors which are known as symmetrical components of…
Synchronous Generator Salient Pole vs Non Salient Pole
Salient Pole Synchronous Alternator: Salient pole Generators will have large diameter and short axial length Pole shoes cover 2/3 of the pitch Salient Poles are laminated in order to reduce eddy currents…
Why Armature is placed on Stator for Synchronous machines
Operation principle of synchronous machine is quite similar to dc machine. However difference exists in the synchronous machine as there is no need to rectify the time varying emf generated…
Advantages and Disadvantages of Slip Ring Induction Motor
Advantages: High Starting torque with low starting current. Maximum starting can be attained in the slip ring motor compared to squirrel cage motor by inserting an external resistance in each…
Squirrel Cage Induction Motor vs Slip Ring Induction Motor
Advantages of Squirrel-Cage Induction Motors The advantages of squirrel-cage motors compared with the slip ring induction motors are given below (i) They are more robust and cheaper (ii) Comparatively they have  higher efficiency…
How RTD Measuring the Temperature
Measuring temperature with RTD / Resistance thermometer The RTD resistance will change with respect to the temperature. So temperature will be measured by using the RTD resistance. The simplest way to…
Why Bias used in Proportional Controller ?
The P-Only Algorithm The P-Only controller computes a CO action every loop sample time T as:  CO = CObias + Kc∙e(t) Where: CObias = controller bias or null value…
