140 likes | 353 Views
INTRODUCTION 2 TYPES ; i. STAR NETWORK ii. DELTA NETWORK. 3 NETWORK TERMINAL. TRANSFORMATION STAR - DELTA. A. Ra. R1. R3. N. Rc. Rb. C. B. R2. c. B. DELTA. STAR. FORMULA ;. Transform star to delta R1 = Ra + Rb + RaRb/Rc R2 = Rb + Rc + RbRc/Ra R3 = Ra + Rc + RaRc/Rb. A. R3.
E N D
INTRODUCTION2 TYPES ;i. STAR NETWORKii. DELTA NETWORK 3 NETWORK TERMINAL
TRANSFORMATION STAR - DELTA A Ra R1 R3 N Rc Rb C B R2 c B DELTA STAR
FORMULA ; Transform star to delta • R1 = Ra + Rb + RaRb/Rc • R2 = Rb + Rc + RbRc/Ra • R3 = Ra + Rc + RaRc/Rb
A R3 R1 C B R2 TRANSFORMATION DELTA-STAR A Ra N Rc Rb B C
FORMULA ; Transform delta to star • Ra = R1R3/ R1+R2+R3 • Rb = R1R2 / R1+R2+R3 • RC = R2R3/ R1+R2+R3
A 4 8 C B 6 EXAMPLE Problem 1 Refer to the circuit below, transform the circuit to Star network
Answer • Ra = 8x4 / (8+6+4) • = 32/18 = 1.78 Ω • Rb = 8x6/ (8+6+4) • = 48/18 = 2.67Ω • Rc = 6x4 / (8+6+4) • = 24/18 = 1.33Ω
EXAMPLE Problem 2 Refer to the circuit, calculate ; • Equivalent resistance, RT • Total of current, IT 40 20 A 50 10 30 C B 30V
Solution ; The steps ; • Mark points A, B, C at each node to represent each of the resistance R1, R2 and R3. • Draw the Delta with the resistances taken as R1, R2 and R3. • Convert Delta to Star shape to find the value of Ra, Rb and Rc
Ra = 20 ohm • Rb = 5 ohm • Rc = 4 ohm
Answer ; • RT = 22.67 Ω • IT = V/RT = 30/22.67 = 1.32 A
EXAMPLE Problem 3 Refer to the circuit, calculate ; • Equivalent resistance, RT • Total of current, IT