PHEP 23

Question 1

What component allows transmission of electricity between insulated circuits?

Answer 1

Transformers

Question 2

What winding that receives energy inductively?

Answer 2

Secondary Winding

Question 3

What characteristics do transformer output power have compared to input?

Answer 3

Different voltage at same frequency

Question 4

What type of AC machines are Transformers?

Answer 4

Static AC Machines

Question 5

What is the relationship between current, voltage and turns of wire?

Answer 5

V_1 * I_1 = V_2 * I_2
V_1 / T_1 = V_2 / T_2
I_1 * T_1 = I_2 * T_2

Question 6

What type of transformer has a higher voltage on the secondary winding?

Answer 6

Step-up Transformer

Question 7

What type of transformer only has 1 physical winding?

Answer 7

Auto-transformer

Question 8

What should never be done to the secondary of a potential transformer?

Answer 8

Short Circuited

Question 9

How are the windings wound on core configuration transformers?

Answer 9

A section of primary and secondary windings are wound around each leg of the core.

Question 10

What does current transformers do?

Answer 10

Steps amount of current down.

Question 11

What is hysteresis

Answer 11

Frictions between molecules due to alternating current

Question 12

How does current change between phase and line inside a Y-connected transformer?

Answer 12

Line Current = Phase Current

Question 13

Street Lighting systems use what kinds of transformers?

Answer 13

Constant current transformers

Question 14

What units do transformer ratings use?

Answer 14

VA, KVA, MVA

Question 15

What is the purpose of a bushing?

Answer 15

Serve as entrances for main leads into a transformer

Question 16

What is the purpose of a conservator

Answer 16

Preserve dielectric strength of transformer oil

Question 17

What should never be done on current transformer secondaries?

Answer 17

Secondaries should never be opened before the device is disconnected from its power source

Question 18

What losses are there in an energized transformer if there is no load on the secondary?

Answer 18

Iron losses

Question 19

In a transformer what must exist between the primary and secondary to supply the required primary current to supply the transformer losses & load on the secondary?

Answer 19

Balanced Condition