問題一覧
1
Delta and three-wire Wye-systems look the same in the field?
- true
2
Consider that a phase sequence into a motor is CBA and the motor is rotating clockwise, which of the following sequences will cause the motor to rotate counterclockwise?
- ABC
3
What is recommended to take place before working on a corner pole to ensure that the jumpers will be reconnected properly?
- The jumper connections should be recorded
4
A parallel circuit is a circuit where?
- There is more than one path for current to flow
5
Inductance can be increased by?
Coiling the conductor
6
In a series circuit what remains constant throughout the the circuit?
- Amperage
7
A short circuit is defined as
A circuit where the load has been bypassed
8
Rotating a magnet near a conductor produces a current because?
The electrons are repelled and attracted due to the law of charges
9
All of the customer owned, three-phased motors on a distribution circuit spin in the same direction
true
10
Frequency
- The number of time that a generator rotates
11
A series circuit is a circuit where?
- There is only one path to follow
12
What is used to measure reactive power in a pure inductive circuit
- VARs
13
When current is in phase with voltage..
- They both rise and fall at the same time
14
In a parallel circuit, what remains constant throughout the circuit?
Voltage
15
In a open circuit, current will not flow
- True
16
What is an advantage of a three-phase system over a single-phase system?
- A 73% increase in power
17
Four wire Wye-systems are the overall preferred system by utility companies because?
- it’s more reliable in regard to fault protection
18
Induction only occurs?
- When the magnetic field expands and collapses
19
Phasing out is necessary when?
- Equipment is out dated and causes power factor problems
20
What effect do coil jumpers have on a power line circuit?
They increase inductance
21
If the phase voltage (phase-to-ground) of a Wye system is 12000 volts, what is the line voltage (phase-to-phase)?
- 20800 volts
22
Why are capacitors installed on power lines?
- To increase apparent power?
23
RMS stands for root mean square and is?
- a value of AC voltage that will produce the same amount of power as a like value of DC
24
A sine wave can be defined as?
- A graphical representation of what is happening to voltage in an AC circuit over time
25
The strength of generated voltage depends on three things. Which of the following is one of them?
- The strength of the magnetic field