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Electrical Lab Transformers Period 3 SAIT-Alberta > Autotransformers > Flashcards

Flashcards in Autotransformers Deck (9)
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1

What is the main principles of operation in an autotransformer?

Electromagnetic induction;

Mutual and Self.

2

What are the two autotransformer windings called?

Common winding;

Series winding.

3

Does the transformer ratio of volts/ turn still apply to autotransformers?

Yes, the V/T of the common and series windings will be identical.

4

When comparing mutual induction transformers and autotransformers of similar coils, which has a higher capacity?

The autotransformer.

5

What is transformed apparent power?

The VA that is transformed through mutual induction in the common winding.

SX = VCom • ICom.

6

What is conducted apparent power?

The VA that is conducted, through the series winding.

SC = VCom • ISer.

7

The total apparent power of an autotransformer is ____________.

The sum the of conducted and transformed apparent power.

8

What is an autotransformer best suited for?

Small Voltage changes (Variac);

When smaller, cheaper, better Voltage regulation and higher capacity (over mutual induction transformers) is desired;

 

9

What are the major flaws of autotransformers?

They do not isolate the secondary from ground;

Higher available fault current;

Equipment may see source voltage in a step down common winding failure.