2-1-13

If the voltage across a winding of a wye-connected device is 480 volts, the line-to-line voltage would be ? . Select one: a.220 V b.277 V c.480 V d.830 V

d. 830 V

A 3-phase power source can be produced by rotating a magnetic field through three sets of coils arranged ? apart. Select one: a.30° b.60° c.90° d.120°

d.120°

For a wye connected device, the line voltage is higher than the phase voltage by a factor of ? . Select one: a.0.637 b.0.707 c.1.414 d.1.73

D. 1.73

A delta-connected device draws 200 amperes through each of the windings. The current through each of the lines is ? . Select one: a.127 A b.141 A c.283 A d.346 A

D. 346 A

A device is wye connected and has a phase voltage of 240 volts. What is the line voltage? Select one: a.152.9 V b.169.7 V c.339.4 V d.415.2 V

D. 415.2 V

For a wye connected device, the line current is equal to the ? current. Select one: a.average b.effective c.peak d.phase

D. Phase

A system that has a common connection for all three windings is ? connected. Select one: a.delta b.phase c.series d.wye

D. Wye

There is a point in a cycle when all three phases are at maximum. Select one: True False

False

There is a point in a cycle of a 3-phase voltage system when one phase is at zero while the other two phases are not. Select one: True False

True

Three-phase systems are used because of their technical and economic advantages. Select one: True False

True

Most electric power generated today is ? . Select one: a.2-phase b.3-phase c.DC d.single phase

B. 3-phase

Line voltage of a delta wired system is equal to phase voltage because the two are in ? with each other. Select one: a.common b.parallel c.series d.sync

B. Parallel

In a delta connection, the three windings are connected ? . Select one: a.180° apart b.at a common point c.end to end d.in parallel

C. End to end

Line current of a wye wired system is equal to the phase current because they are in ? with each other. Select one: a.common b.parallel c.series d.sync

C. Series

For a delta connected device, the line current is equal to ? times the phase current. Select one: a.0.637 b.0.707 c.1.414 d.1.73

D. 1.73

A device is delta connected and has a phase current of 600 amperes. What is the line current? Select one: a.382.2 A b.424.2 A c.848.4 A d.1,038 A

1038

For a ? connected device, the line voltage is equal to the phase voltage. Select one: a.delta b.parallel c.star d.wye

A. Delta

The two basic wiring schemes for 3-phase systems are wye and ? connections. Select one: a.delta b.progressive c.star d.triple wound

A. Delta

A 3-phase generator produces three ? voltages. Select one: a.equal b.in phase c.secondary d.unequal

A. Equal