eg 2 week 2 Flashcards
how much are 3 phase generators spaced apart from each other?
120 degrees
how many phases are delivering power when 1 phase is at 0?
2
in a wye system, coil current and phase current are?
the same
in a in a delta system, coil voltage and phase voltage are?
same
in a delta system, phase current is higher than coil current by a value of
1.732
in regards to fault protection, which system is more reliable?
four wire wye
which two systems appear the same in the field?
delta - ungrounded wye
all generators connected to a regional transmission network are all the same angle of rotation at any given time?
true
if a generator begins to lead or lag, protective equipment will automatically
open
most rotation errors in isolated locations on distribution lines are usually caused by?
line workers
changing the sequence of rotation will change what?
direction of motors
first step to phasing properly is to ?
verify meter is working properly
when the magnetic field peaks between the stator poles, what happens to the current?
induced in the rods of rotor
3 phase power delivered to a load is?
constant
the predominant electrical system used today is
wye
in a delta system voltage stays
the same
in a wye coil current stays
the same
phase current =
coil current x 1.732
a phasing meter is a what?
high voltage meter
in a delta system coil voltage =
system voltage
in a wye system voltage =
coil voltage x 1.732
what system is the most widely used system?
four wire wye system
if the phase sequence is unchanged , rotation will remain unchanged, true or false
true
in a delta system phase current =
coil current x 1.732
in a wye system coil current =
phase current
what has no reference to ground?
delta
what has no neutral?
delta
what are the same on a wye?
coil current and phase current
is there rotation for single phase?
no
what would be an indication you are in phase?
0 volts in sequence
what is a stator in a motor?
stationary part
what is a rotor in a motor?
the rotating part
line sequence a linecrew might spray in the street before working a pole?
ground grid
what is required before using a phasing meter?
phase tester
