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WorksheetsENG4216
Total questions: 30
Worksheet time: 1hrs 28mins
Lock out / tag out is the procedure.
To keep the machines in lock forever
To put tags with names of machine parts
To carry out maintenance jobs safely
To get permission for maintenance job
If you see damaged a wire during maintenance job then what action shall you take.
Replace the damaged wire with any wire
Ignore the damage and cover it with other wires
Just put a warning label
Repair it as per the manufacturer standards without reducing the protection
What preparations must be made before work to handle any emergency?
Locate nearest first aid and firefighting equipment
Locate nearest bathroom
Locate nearest mall
Locate nearest cafeteria
Work permit is a document used to;
Estimate the cost of any maintenance
Take permission to start any maintenance work
Ensure the availability of spare parts needed for maintenance
Describe the skills of the technicians doing maintenance work
How to get authorization to carry out any maintenance work in industry?
By taking verbal permission
By asking your supervisor on email
By using work permit form
By asking any colleague
A step up transformer;
Decrease the voltage at output
Keep the voltage same at input and output
Increase the voltage at output
Changes the voltage all the time
Basic construction of transformer contains three parts, which are;
Primary winding, Secondary Winding and Rotor
Rotor, Stator and Winding
Primary winding, Secondary Winding and Iron core
Armature, Shaft and bearings
A transformer used to transfer complex signals, containing large number of frequencies, form one circuit to another is called;
Signal Transformer
Power Transformer
Auto Transformer
Instrument Transformer
Which of the following turns ratio is considered a “step down” transformer?
2 : 3
2 : 5
10 : 1
1 : 1
Power loss caused by magnetism that remains in a material after the magnetizing force has been removed is called;
Eddy current loss
Hysteresis loss
Resistive loss
Dielectric loss
What type of power transformer installation is commonly used for industrial applications?
Delta – Star (Δ - Y)
Star – Delta (Y - Δ)
Star – Star (Y - Y)
Delta – Delta (Δ - Δ)
What type of power transformer installation is commonly used for interior wiring systems?
Delta – Star (Δ - Y)
Star – Delta (Y - Δ)
Star – Star (Y - Y)
Delta – Delta (Δ - Δ)
Describe the construction type of 3 phase transformer shown in the picture.
Air core
Core type
Shell type
None of the choices
What is the connection type of 3 phase transformer as shown in the figure?
Star Delta
Star Star
Delta Star
Delta Delta
Which 3phase transformer is used to convert 3-wire system to 4-wire system with neutral available.
Delta – Star (Δ - Y)
Star – Delta (Y - Δ)
Star – Star (Y - Y)
Delta – Delta (Δ - Δ)
What is the function of oil in a transformer?
for cooling and insulation
for hydraulic functions
for reducing friction between moving parts
for load balancing
Which of the following testing that will check the insulation integrity of the transformer?
insulation resistance test
winding resistance test
short circuit test
voltage test
Which of the following is a requirement for the parallel operation of transformers?
The same bushings
The same weight
The same price tag
The same percent impedance
The leads from the primary and secondary windings must be safely brought out of the transformer’s tank to form a terminal connection point for the line and load connections. This is done by using a component called ____
Bushings
control panel
Terminal Block
Switches
What type of transformer cooling is described in the picture?
ONAN
ONAF
OFAF
ODAF
What type of transformer cooling is described in the picture?
ONAN
ONAF
OFAF
OFWF
The voltage between any two lines of 3 phase circuit is called ______.
line voltage
phase voltage
open circuit voltage
short circuit voltage
In a 3-phase, Star (Y) system, the voltage between any line and neutral is called ____
line voltage
phase voltage
open circuit voltage
short circuit voltage
Determine the current in the secondary circuit of transformer as shown.
10A
1A
5A
0A
Determine the voltage across the load in the transformer circuit shown.
120V
12V
10V
1V
In a 3phase, delta-star (Y) connected transformer, if the secondary line-to-line voltage is 415V, what is the phase voltage on the secondary?
239.6V
415V
127.5V
718.8V
What is the primary impedance of a transformer with a secondary impedance of 100 Ω and a turns ratio of 100:1?
1 kΩ
1 MΩ
100 Ω
10 Ω
What is the turn’s ratio of a transformer that has primary voltage of 600 V and secondary voltage of 100 V?
6:1
5:1
3:1
10:1
Transformers are rated in terms of _____
Watts (W)
Volt-ampere (VA)
horsepower (hp)
Reactive volt-ampere (VAR)
A transformer used to step up or step down the voltage in transmission/distribution systems, is called ____
power transformer
instrument transformer
audio transformer
auto-transformer
