Electrical Engineering

 RESISTANCE IN SERIES  & PARALLEL CONNECTION (i) Series Connection (ii) Parallel Connection RESISTNCE IN SERIES The resistors R1, R2, R3 are connected in series across the supply voltage V .  The total current flowing through the circuit is I . The voltage across R1, R2, R3 are V1, V2, V3 respectively. V1=I*R1, V2=I*R2, V3=I*R3 V=V1+V2+V3 I*R=I*R1+I*R2+I*R3 I*R=I*(R1+R2+R3) R=R1+R2+R3 RESISTNCE IN PARALLEL The resistors R1, R2, R3 are connected in series parallel across the supply voltage V .  The total current flowing through the circuit is I . The current flowing through R1, R2, R3 are I1, I2, I3 respectively. I1=V/R1, I2= V/ R2, I3= V/ R3 I=I1+I2+I3 V/ R= V/ R1+ V/ R2+ V/ R3 V/ R= V/ (R1+R2+R3) 1/R=1/R1+1/R2+1/R3 For More Topics: Follow Us On: FACEBOOK

CONDUCTANCE It is the measure of how easily the current will flow through the conductor. The reciprocal of Resistance is called CONDUCTANCE and is denoted by "G" . Its unit is "MHO" or "SIEMENS".          G = 1/R = I/V. CONDUCTIVITY Conductivity or SPECIFIC CONDUCTANCE is the reciprocal of specific resistance. It represented as σ (SIGMA) and its unit is Mho/Mtr. σ  = 1/  ρ. For More Topics: Follow Us On: FACEBOOK

  GALVANIZATION It is the process of applying a protective ZINC coating to IRON/ STEEL to protect from RUSTING . The  PROCESS as follows: Rust removed iron piece in the mixture of ZINC CHLORIDE & AMONIUM CHLORIDE . After that, the Iron piece again dipped in MOLTEN ZINC at 450degree . The Galvanized Material allowed to pass through HOT ROLLER S to remove the EXCESS ZINC on the surface to provide uniform zinc coating. Finally it placed in HOT AIR CHAMBER for drying. For More Topics: Follow Us On: FACEBOOK

 TRANSFORMER RATING CALCULATION In this BLOG, we are going t discuss about the Calculation of   TRANSFORMER RATING : For Eg:- Maximum Load = 400KW. Diversity Factor = 0.7 Therefore, Expected Load in KW = 400*0.7 = 280KW Expected Load in KVA = 280/ 0.9 = 311KVA (Power Factor Considered as 0.9) 85% Loading Capacity is considered. Required KVA Rating = 311/ 0.85 = 366KVA Therefore, 400KVA transformer is used.  (400KVA is the n ext Available Rating above 366KVA) For More Topics: Follow Us On: FACEBOOK

LAW'S OF RESISTANCE The RESISTANCE of a Conductor varies, Directly with its LENGTH . Inversely to its CROSS-SECTIONAL AREA. Depends on NATURE of the materials. Depends on the TEMPERATURE.                                       R  ∝  L,  R  ∝  1/ A                                       R   ∝  L/A                                       R  =  ρ  * (L/A) Where   ρ is called SPECIFIC RESISTANCE (RESISTIVITY) and its unit is Ohm-Mtr . For More Topics: Follow Us ON: FACEBOOK  

 ELECTRIC CURRENT The continuous flow of electrons constitutes CURRENT. It denotes by "I" and its unit is AMPERE(A ). Current is also treated as CHARGE/TIME . So the unit is also COULOMB/SEC . ELECTRIC POTENTIAL Defined as the work done in bringing a unit positive charge from infinity to that point against the electric field. It denotes by "V" and its unit is Volt(V) . RESISTANCE The property of a conductor  by which it opposes the flow of current. It denotes by "R" and its unit is OHM( Ω) . Resistance (R)= Voltage (V)/ Current (I). For More Topics: Follow Us On: FACEBOOK