Quiz sheet for autotransformers

An auto-transformer has 

A) a section of winding that is common to both primary and secondary windings

B) has two electrically isolated windings

C) has electric and magnetic isolation 

D) the same number of turns on the primary winding as on the secondary

ANSWER: A

Autotransformer's are an excellent choice for 

A) reduced voltage motor starting

B) isolation of supply from ground

C) Protected Extra Low Voltage supply

D) reducing voltage for swimming pools

ANSWER: A

Compared to a double wound transformer of the same rating, an auto-transformer 

A) requires less material to manufacture 

B) is larger in physical size

C) has lower efficiency

D) has higher losses

ANSWER: A

If the meter connected to a current transformer is to be removed while the supply is energised, the current transformer must be 

A) short circuited on the secondary terminals

B) short circuited on the primary terminals

C) open circuited on the secondary terminals

D) open circuited on the secondary terminals

ANSWER: A

State one example of an application of an auto transformer

A) Motor starter

B) Current transformer

C) Potential transformer

D) Isolation transformer.

ANSWER: A

The current in the common section of an auto-transformer when loaded is equal to the

A) difference between the primary and secondary currents

B) phasor sum of the primary and secondary currents

C) phasor difference between the primary and secondary currents

D) sum of the primary and secondary currents

ANSWER: A

Last modified: Sunday, 30 May 2021, 8:49 PM