Unit 4: Poly Phase Circuits Flashcards
(11 cards)
1
Q
Advantages of 3 Phase Circuits [3]
A
- Greater power density @ same ampage
- Provides rotating mag field (instead of pulsating)
- Lower wiring + labour costs
2
Q
Power Delivery
A
Delivers constant instantaneous electrical power.
Allows motors to be subject to smooth Torque.
3
Q
Conducting ability
A
Transmits 3 times more power w/ only 1 additional wire.
4
Q
Main 3-Phase Configurations
A
- Star Connection (Y)
- Delta Connection (Δ)
5
Q
Star Connection Overview
A
- Circuit can be solved per phase for balanced load
- Angle between V & I is load impedance angle
6
Q
Star Phase Voltages
A
Van = V < δ
Vbn = V < δ - 120
Vcn = V < δ +120
7
Q
Star Phase Currents
A
Ia = I < θ
Ib = I < θ - 120
Ic = I < θ +120
8
Q
Delta Connection Overview
A
- Circuit can be solved per phase for balanced load
- Angle between V & I is load impedance angle
9
Q
Delta Phase Voltages
A
Vab = V < δ
Vbc = V < δ - 120
Vca = V < δ +120
10
Q
Delta Phase Currents
A
Ia = I < θ
Ib = I < θ - 120
Ic = I < θ +120
11
Q
What if Vrms = Vph = V & Irms = Iph = I?
A
For Star => VL = V*√3
IL = I
For Delta => VL = V
IL = I*√3
