NETA LEVEL 2 EXAM QUESTIONS WITH COMPLETE
SOLUTIONS VERIFIED
Losses in a rotating machine due to heat can have a dramatic effect on efficiency.
Which category of losses has the least influence on electric motors?
Friction
Core Losses: The energy required to magnetize the core and eddy current losses in the
stator core.
Stator Losses: I2R heating of the stator due to current flow in the stator windings.
Rotor Losses: I2 heating of rotor bars as induced current flows.
Friction and Windage Losses: Bearing and air friction on the rotor shaft and cooling fan.
Stray Load Losses: Leakage reactance fluxes induced by the load current.
Which of the following protective functions requires the least energy to trip a
circuit breaker?
L
S
I
G
G - ground fault
The sensing element or setting of a motor overload device that is not sufficient to
start or carry the load of a motor marked with a service factor of 1.15 or greater
shall not exceed _____
140%
What is the difference between a thermogram and a thermal image?
There is no difference; both terms refer to the same thing.
How many time constants are required for circuit parameters to normally reach
their final value in an inductive circuit?
5
, The time it takes a fiber optic signal to travel from one point to another over a
transmission channel is called
Propagation delay
True or False? With tight-buffered fiber optic cable, the buffering material does
not come in direct contact with the fiber.
False
Thermal relays are commonly used in motors against over-currents, which is
drawn because of:
Overloads
A three-phase 480-208Y/120V transformer rated 750kVA with an impedance of
4.6% is to be protected by a circuit breaker on the primary side with fuse
protection on the secondary side. What is the maximum standard trip setting that
should be used for this breaker?
2500A
NFPA70 Table 450.3(B)
According to ANSI/NETA MTS, how often should ground systems be electrically
tested assuming a multiplier of 1.0?
Once every two years
Which of the following components would you not expect to find inside an
Automatic Transfer Switch?
Current balance relay
Generally, high current test sets:
Provide high test currents at 10 volts or less
What are the risk categories used to determine maintenance and testing
procedures for SF6 gas-insulated equipment?
New gas, non-arced, normally arced, and heavily arced
Calculate the percentage differential mismatch for an electromechanical relay
protecting a 138kV-69kV Delta-Wye 50MVA Transformer with 250:5 CTs on the
primary and 500:5 CTs on the secondary, with CT ratio taps on the relay set to 5A
on the high side and 9A on the low side.
3.78%
SOLUTIONS VERIFIED
Losses in a rotating machine due to heat can have a dramatic effect on efficiency.
Which category of losses has the least influence on electric motors?
Friction
Core Losses: The energy required to magnetize the core and eddy current losses in the
stator core.
Stator Losses: I2R heating of the stator due to current flow in the stator windings.
Rotor Losses: I2 heating of rotor bars as induced current flows.
Friction and Windage Losses: Bearing and air friction on the rotor shaft and cooling fan.
Stray Load Losses: Leakage reactance fluxes induced by the load current.
Which of the following protective functions requires the least energy to trip a
circuit breaker?
L
S
I
G
G - ground fault
The sensing element or setting of a motor overload device that is not sufficient to
start or carry the load of a motor marked with a service factor of 1.15 or greater
shall not exceed _____
140%
What is the difference between a thermogram and a thermal image?
There is no difference; both terms refer to the same thing.
How many time constants are required for circuit parameters to normally reach
their final value in an inductive circuit?
5
, The time it takes a fiber optic signal to travel from one point to another over a
transmission channel is called
Propagation delay
True or False? With tight-buffered fiber optic cable, the buffering material does
not come in direct contact with the fiber.
False
Thermal relays are commonly used in motors against over-currents, which is
drawn because of:
Overloads
A three-phase 480-208Y/120V transformer rated 750kVA with an impedance of
4.6% is to be protected by a circuit breaker on the primary side with fuse
protection on the secondary side. What is the maximum standard trip setting that
should be used for this breaker?
2500A
NFPA70 Table 450.3(B)
According to ANSI/NETA MTS, how often should ground systems be electrically
tested assuming a multiplier of 1.0?
Once every two years
Which of the following components would you not expect to find inside an
Automatic Transfer Switch?
Current balance relay
Generally, high current test sets:
Provide high test currents at 10 volts or less
What are the risk categories used to determine maintenance and testing
procedures for SF6 gas-insulated equipment?
New gas, non-arced, normally arced, and heavily arced
Calculate the percentage differential mismatch for an electromechanical relay
protecting a 138kV-69kV Delta-Wye 50MVA Transformer with 250:5 CTs on the
primary and 500:5 CTs on the secondary, with CT ratio taps on the relay set to 5A
on the high side and 9A on the low side.
3.78%
