Electrical Chapter 11 Quiz Flashcards
What are the two windings of a transformer called?
Primary and Secondary
If a transformer has a turns ratio of 1:4, what is the voltage ratio?
1:4
If a transformer has a turns ratio of 1:4, what is the current ratio?
4:1
If a transformer has a turns ratio of 1:4, what is the power ratio?
1:1
If a transformer has a turns ratio of 1:4 and 115V is applied to the primary, how many volts are on the secondary?
460V (115x4)
Why are transformer iron cores laminated?
Minimize Eddy Current Losses, which produce heat
What type of electrical service is most common for residential dwellings?
120V/240V single phase
Why do control transformers usually have two primary coils?
So you can use different voltages (Tyically 240V or 480V)
What do “X” markings on a transformer represent?
Lower Voltage
What do “H” markings on a transformer represent?
High Voltage
When connecting the primary of a control transformer to high voltage, are the coils connected in series or parallel?
Series
When connecting the primary of a control transformer to low voltage, are the coils connected in series or parallel?
Parallel
Is a transformer’s VA rating based on the primary ot secondary of a the transformer?
Secondary
What information is needed to size a transformer?
•Input Voltage Available
•Output Voltage Desired
•Output Current Required
Can you use a transformer for DC voltage?
No
