WorksheetsLesson 6: Power Generation and Distribution
Total questions: 24
Worksheet time: 13mins
In North America, power is generated at a frequency of ? .
25 Hz
50 Hz
60 Hz
120 Hz
A(n) ? is a device that indicates whether two AC sources to be connected in parallel are in the correct phase relationship.
alternator
potentiometer
rotor
synchroscope
The ? is the voltage measured line-to-line.
line current
line voltage
winding current
winding voltage
The most efficient way to send electric power over transmission lines is at the lowest current possible.
True
False
The ? is the current flow through the individual windings.
line current
line voltage
winding current
winding voltage
A landfill generator runs on the methane gas created by decomposing trash.
True
False
The power in a single-phase circuit drops to zero ? every cycle.
once
twice
three times
four times
In an electric generating power plant, all generators must be connected in ? .
chain
line
parellel
series
The ? is the voltage measured across the windings.
line current
line voltage
winding current
winding voltage
A ? produces energy when a rotating coil cuts through magnetic flux.
generator
motor drive
synchroscope
transformer
The ? is the current flow through the lines to a load.
line current
line voltage
phase current
phase voltage
What was the primary transmission line problem that led up to a sequence of events that eventually caused the East Coast power blackout on August 14, 2003?
A car accident caused a transmission line to fall.
A wind storm caused multiple transmission poles to break.
An overhead transmission line became overheated and sagged, shorting to ground when it came into contact with a tree.
None of the above.
A(n) ? is a machine that converts mechanical energy into electrical energy by means of electromagnetic induction.
electrical transmitter
generator
motor drive
transformer
Which factors determine the amount of voltage produced by a generator?
I. The number of turns
II. The speed of rotation of the rotor
III. The strength of the magnetic field
IV. The load on the generator
I. and II. only
I. and III. only
II. and III. only
I., II., and III.
A stronger magnetic field, more turns, and faster rotation produce a higher voltage from a generator.
True
False
? is a method of synchronizing generators.
Chaining
Lights-out
Marking
Phase-timing
Utilities normally generate ? .
single-phase AC power
single-phase DC power
3-phase AC power
3-phase DC power
Magnetic force is used to rotate the coils in a generator.
True
False
In the three-lights-out method, a lamp is connected as a load across each phase of the two sources, A to A, B to B, and C to C.
True
False
In the one-light-out method, phases are connected A to B, B to A, and C to C.
True
False
In a 3-phase circuit, power varies during a cycle but never falls to zero.
True
False
Transformers are usually used to step up voltage at the point of use.
True
False
If the line voltage is 480 volts as shown, the winding voltage is ? .
120 V
208 V
240 V
277 V
How much power in kilovolt-amperes is delivered to a 3-phase transformer when the line voltage applied is 480 volts and the line current is 12 amps? (Round the FINAL answer to two decimal places.)
(a)
