Answer ALL questions. Look for any feedback given if you get an answer incorrect. Keep choosing an answer until you get it correct. CORRECT or INCORRECT answers are indicated at the TOP of the page. A score is given at the TOP of the page when the exercise has been completed.
Which induction principle do transformers use?
mutual induction
static induction
self induction
none of the answers shown here
transformers suffer from losses in the form of heat. What is the name given to these losses?
Copper losses
Iron losses
Power losses
Current losses
Iron losses in a transformer are in two different forms. Eddy currents are one form. What is the other?
copper losses
hysteresis losses
current losses
magnetic losses
What type of transformer is shown here that can output different voltage levels simultaneously?
auto transformer
multi-tapped transformer
heavy power transformer
low loss transformer
What are eddy current losses?
heat loss caused by the windings
magnetic loss in the transformer
induced currents are retained in the iron core
degradation of the iron core
How are eddy current losses reduced?
laminating a silicon/iron core
using high quality copper conductors
cooling the transformer
using a circular core (toroidal)
A transformer is rated at 10kW but is only delivering 9.8kW. Copper losses are 0.33kW and Iron losses are 0.2kW. Calculate the efficiency of the transformer.
90.4%
98%
88.6%
99%
A transformer has 400 turns (Pri) and 200v (Pri), it produces 100v (Sec) with load = 10 ohms. Calculate current (Pri).Click here for formula (if you really need it!!)
5A
10A
2.5A
15A
How is a transformer rated for power?
V x I
V x I x Cos0
1.732xVxIxCos0
V/R
A 3 phase 10kVA transformer has a pf=0.9. Calculate the Line current for this transformer.
16A
20A
6A
26A
What type of transformer is shown here?
multitapped
auto
heavy duty
low-loss
What type of transformer is shown in this circuit diagram?
high frequency
low loss
auto
multi tapped
"With this type of transformer, there is a danger that a short-circuit in the windings could cause 'mains' voltage to appear at the secondary terminals". Which type of transformer is being referred to here?