A step-up transformer has _____ number of turns on primary winding and _____ number of turns on secondary winding.

A. Less, More

B. More, More

C. More, Less

D. Less, Less

Answer 

A. Less, More

Explanation 

• A step-up transformer has more secondary winding than primary windings, this increases the voltage from the primary to the secondary side of the transformer.
• A transformer in which the output (secondary) voltage is greater than its input (primary) voltage is called a step-up transformer. The step-up transformer decreases the output current for keeping the input and output power of the system equal.
• A Step-up transformer is used in transmission lines for transforming the high voltage produced by the alternator. The power loss of the transmission line is directly proportional to the square of the current that flows through it.
• The output current of the step-up transformer is less, and hence it is used for reducing the power loss. The step-up transformer is also used for starting the electrical motor, in the microwave oven, X-rays machines, etc.
• The number of turns on the secondary of the transformer is greater than that of the primary, i.e., T2 > T1. Thus the voltage turn ratio of the step-up transformer is 1:2. The primary winding of the step-up transformer is made up of thick insulated copper wire because the low magnitude current flows through it.

Power System MCQs With Explanation 

 

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