3 Phase Flashcards
Wye connections are characterized by?
The fact that one terminal of each of the devices is connected together
In a wye connection, phase voltage is less or more than line and by what
Phase voltage is less than line by root3
In delta, phase voltage is what to line voltage
Phase and line the same in delta
Line current in delta is what to phase current
Line current in delta is more than phase by root3
Wye load has a voltage of 480v , what is the voltage dropped across each phase ?
480/root3 = 277.13 Ephase
Delta connection has a voltage of 560V how many colts dropped across each phase?
El =EP in delta = 560
A c generators are commonly referred to as?
Alternators
The voltage is induced in the part of the alternator called?
Armature
Between maximum positive and maximum negative values of a single phase alternating current or voltage the difference is ?
180
Between maximum positive and maximum negative of one phase of a three phase alternating current or voltage , difference of?
180
In wye connected balanced 3 phase system the line current values and the winding current values are
The same
In a balanced delta system, the line and coil voltages are
The same
A 3 phase a c generator is connected in WYE . Each 3 coil windings rated 4000 V A and 120 bolts the line voltage would be?
- 120xroot 3
3 phase generator connected in WYE . Voltage of each phase or coil would be?
- 480/root3
In a delta system line voltage to coil voltage is what ?
Equals coil voltage
In a 3 phase WYe circuit the power in WATTS is equal to?
Cosine/_ x ELine x I Line x root 3
Improvement of the power factor of a three phase circuit has this effect on the a c circuit
Decreases volt amps
Decreases current for the same power output power out
Line to line voltage of a c wye generator is 208 what’s voltage rating of each winding
- 208/ root 3
In three phase power systems , the delivered power…?
Never falls to 0
The three phase connection which one end of each of the windings are connected together is called the
WYE connection
In a three phase connection, voltage measured from one external voltage connector to another is the ________ voltage
Phase
In a 3 phase connection the current that flows in the winding is the ______ current
Phase
Line current and phase current are the same in?
WYE configuration
Three phase connection which all three of the coils are connected end to end to form a closed loop is the _______ connection?
Delta
Multiplying apparent power by the power factor gives you what?
True power
Calculating power ina. Three phase circuit, the product of line current and power factor are multiplied by what?
Square root 3
If a 3 phase load is purely reactive then power calculated has units of?
Vars
