3rd year level 1 lesson 5
73%
By stringing a fourth wire and reconnecting the substation transformer secondaries from delta to wye, the capacity of the circuit can be increased by ? .
False
In a delta connected 3-phase system, the line current is equal to the phase current.
Only one voltage is available between any two wires
In a delta system, ? .
1.73
In a delta system, the line current is equal to ? times the phase current.
False
In a wye connected system, the amount of voltage from the tip to the center of the Y (across a single winding) is known as the line voltage.
1.73
In a wye connected system, the line voltage is equal to ? times the phase voltage.
Line
In a wye connected system, the voltage from tip to tip (between the lines) is known as the ? voltage.
58%
The current flow in a wye circuit is about ? less than in an equivalent delta circuit.
3 wire
The delta system is also called a ? system.
Y
The two basic types of 3-phase distribution systems are symbolized by a delta symbol (Δ) and a(n) ? .
12470 Y
When a 3-phase, 3-wire, 7,200-volt delta circuit is cut over to a 3-phase, 4-wire wye circuit, the line voltage is ? .
Phase
In a delta system, the line voltage and the ? voltage are the same.
True
In a delta system, the three phases are connected in series.
True
The most commonly used 3-phase distribution system is the wye system.
7,200/12,470Y V
The most popular distribution voltage in use today is the ? system.
Wye
When a 3-phase transformer bank is connected in a ? configuration, one end of each coil is connected together at a common point.
200 amps
If the line current in a wye system is 200 amperes, the phase current is ? .
2400 wye
If the line voltage in a delta system is 2,400 volts, the phase voltage is ? .
346 A
If the phase current in a delta system is 200 amperes, the line current is ? .
120 V
If the phase-to-phase voltage in a wye system is 208 volts, the phase-to-neutral voltage is ? .
Phase
The voltage measured across a single winding or phase is known as the ? voltage.
120 degrees
The voltages of a 3-phase system are ? out-of-phase with each other.
4 wire
The wye system is also called a ? system.
False
There are three different voltages available in a wye connected system.