Transformer Types
A transformer used to convert high-voltage from the power company, down to 120 / 240 V to our homes
Distribution Transformer
A transformer has a turns ratio of 1:4, if the secondary is 480v, what is the primary?
120v
A transformer has 8 windings in its primary core and 5 in its secondary coil. If the primary voltage is 240 V, find the secondary voltage.
150V
The output winding of a transformer
Secondary
Volts / Turns
Volts per turn
Transformer with more than one set of lead wires
multi tapped
A transformer has a 240v primary and 120v secondary. With an ohm load of 20 ohms connected, what does Ip equal
3 amps
40V
Any transformer flux that doesn't follow the core, and escapes into the surrounding area.
Flux Leakage
Is=KVA / Es
Primary Current
Transformer with only one set of windings for both the primary, and secondary
auto transformer
A transformer has a turns ratio of 1:4, primary is 120V, what is the secondary voltage
480v
Ep=7200v Es=720v
Find turns ratio
10:1
A transformer core assembled by winding a long continuous tape of metal into a spiral
toroid / tape wound
Z x I =
E (voltage)
The industrial use transformer usually has 240v or 480v primary, then 120v secondary
control
A transformer has a turns ratio of 1:4, on the secondary side a load 8 ohms, and a current flow 11 amp, find Ep
22v
If a transformer has a turns ratio of 5:1, and an input of 240v for the primary, and the load connected has a current flow of 30 amps. What does Ip equal?
6 Amps
A transformer in which the current on the primary, is higher, than the current on the secondary.
Step-up
E/Z
I
A transformer where the winding's are not connected physically
isolation
A transformer has input of 120v for the primary, and the secondary has a current flow of 10 amps, and an impedance of 6 ohms. What is the turns ratio
2:1
A transformer has input of 150v for the primary, and the secondary has a current flow of 15 amps, and an impedance of 20 ohms. What does Ip equal
30 amps
Even when no load is connected, there will be some small current required to magnetize the core
excitation current
To find the total current for the primary side in a multi-tap
Multiply for step up
Divide for step down
then add