Transformers

Which specific type of induction principle do transformers use?
1. mutual induction
2. static induction
3. self induction
4. AC induction
What type of transformer can output different voltage levels simultaneously?
1. auto transformer
2. multi-tapped transformer
3. heavy power transformer
4. low loss transformer
How is a transformer rated for power?
1. V x I
2. V x R
3. V / I
4. V/R
What type of induction does a transformer use?
1. electrical
2. static
3. dynamic
4. self
What is the voltage output of a yellow site transformer?
1. 230v
2. 110v
3. 400v
4. 25v
What RATING is used for transformers?
1. watts
2. VA
3. VAr
4. A
Identify this type of transformer design
1. core-type
2. shell-type
3. toroid-type
4. induction-type
Identify this type of transformer design
1. shell-type
2. core-type
3. toroid-type
4. induction-type
Identify the construction material used in the core of a transformer
1. iron
2. copper
3. nickel
4. aluminium
Identify the type of transformer shown here?
1. polyphase type
2. dual phase type
3. single phase type
4. direct current type
Identify the method not used to cool large transformers?
1. water cooled
2. oil cooled
3. air cooled
4. gas cooled
Identify the gas used to cool and insulate large power transformers?
1. SF6
2. SF2
3. SF4
4. SF8
Identify the type of transformer used for 'step-up' application?
1. powerstation transformer
2. LED lighting transformer
3. worksite (yellow) transformer
4. intruder alarm control panel transformer
Identify this type of transformer design
1. toroid-type
2. RF-type
3. donut-type
4. power-type
a transformer has Vp=200v and Vs=10v. If Np=1000 turns calculate Ns
1. 50 turns
2. 20000 turns
3. 2000 turns
4. 500 turns
a transformer has Ip=12A and Is=3A. If Vs=1000v, calculate Vp
1. 4000v
2. 250v
3. 230v
4. 3333.3v
a transformer has Ns= 5000 turns and Is= 20A. If Np = 1000 turns, calculate Ip
1. 100A
2. 4A
3. 40A
4. 10A
a transformer has Vs=2850v and Vp=500v. If Ip = 16A, calculate Is
1. 2.81A
2. 91.2A
3. 44.4A
4. 0.55A
Identify the type of loss that can occur in the transformer windings
1. copper loss
2. hysteresis loss
3. eddy current loss
4. transient loss
Identify the type of transformer loss that can be reduced by laminating the Iron core
1. copper loss
2. hysteresis loss
3. eddy current loss
4. transient loss
Identify the type of transformer loss that can be reduced by adding silicon to the Iron core
1. copper loss
2. hysteresis loss
3. eddy current loss
4. transient loss
Identify the formula for Transformer Regulation (as a %)
1. (Vno-load – Vfull-load) / Vfull-load (x100)
2. (Vno-load – Vfull-load) / Vno-load (x100)
3. (Vfull-load – Vno-load) / Vno-load (x100)
4. (Vno-load + Vfull-load) / Vfull-load (x100)
a transformer has the following output voltage values; 46v (full load), 48v (no load), 110v (input voltage). Calculate the transformer regulation as a percentage.
1. 2.2%
2. 44.6%
3. 12.8%
4. 4.3 %
a transformer has the following output voltage values; 18v (full load), 24v (no load), 230v (input voltage). Calculate the transformer regulation as a percentage.
1. 5.2%
2. 33.3%
3. 40.8%
4. 14.3 %
a transformer has the following output voltage values; 46v (full load), 48v (no load), 110v (input voltage). Calculate the transformer ratio at full load.
1. 4.8:1
2. 5:1
3. 1:2.39
4. 2.4:1
a transformer has the following output voltage values; 18v (full load), 24v (no load), 230v (input voltage). Calculate the transformer ratio at no-load
1. 9.58:1
2. 1:12.78:
3. 6.85:1
4. 16.66:1
a transformer has the following output voltage values; 46v and 5.5A(full load), 50v and 0.05A (no load), 110v (input voltage). Calculate the transformer power rating at no load
1. 253VA
2. 2.5VA
3. 55VA
4. 16.6VA
a transformer has the following output voltage values; 12v and 0.1A (no load), 8v and 5.5A(full load),100v (input voltage). Calculate the transformer power rating at full load
1. 33VA
2. 12VA
3. 14.4VA
4. 44VA
the output voltage from a transformer need to be measured. How should the voltmeter be connected
1. in series with the supply
2. in parallel with the supply
3. in parallel with the output
4. in series with the output
the input current from a transformer need to be measured. How should the ammeter be connected
1. in series with the supply
2. in parallel with the supply
3. in parallel with the output
4. in series with the output
What type of transformer can operate using a single winding for the input voltage and has a 'tapping' on the same winding for the output voltage?
1. auto transformer
2. multi-tapped transformer
3. large power transformer
4. low loss transformer

Transformers

Transformer Basics 1, types, designs, calculations, ratings and uses - 10 questions from a bank of questions© K.Brown 2025

Transformer Basics 1, types, designs, calculations, ratings and uses - 10 questions from a bank of questions
© K.Brown 2025