Delmars Unit 26 Three questions with complete solutions 2024

Delmars Unit 26 Three-Phase Circuits
The three-phase connection in which one end of each of the windings are
connected together is called a(n) _____ connection.
delta
wye
open delta
open wye - correct answer ✔wye


Which of these formulas is used to calculate total current delivered by the
alternator? - correct answer ✔IL(alt)=


What does EP(Load) represent?
phase current of the load
phase voltage of the alternator
phase voltage of the load
line voltage of the load - correct answer ✔phase voltage of the load


If Load 3 is pure capacitive, the current and voltage are 90 degrees out of
phase with each other and the power factor is zero.
True
False - correct answer ✔True


A wye-connected alternator that has phase voltages of 277 V is feeding two
loads. The first load is wye-connected inductors that have 40 Ω of XL. The
second load is delta-connected capacitors that have XC of 60 Ω. How much is
the alternator phase current?
6.93 A

, 14.93 A
24.62 A
28 A - correct answer ✔6.93 A


In a balanced three-phase system, the conductors need to be only about
_____ the size of conductors for a single-phase, two-wire system of the same
kilovolt-ampere (kVA) rating.
25%
30%
50%
75% - correct answer ✔75%


Which of these formulas is used to calculate three-phase watts of a three-
phase power circuit? - correct answer ✔P=


In a three-phase connection, what is the voltage measured across a single
winding?
line voltage
phase voltage - correct answer ✔phase voltage


A delta connected set of windings has a phase voltage of 480 V. What is the
line voltage?
277.14 V
480 V
831.36 V
1440 V - correct answer ✔480 V


Line current and phase current are the same in the _____ configuration.