# Current Transformer Interview Questions

current transformer interview questions :Current transformer are very useful electrical equipment in the power industry so often asked question about current transformer So this topic are need consider to exam or interview, following best given Current Transformer Interview Questions in that. It will help in your exam or when you will face any interview.

#### 1.what is current transformer ?

• Current transformer means that instrument transformer which have primary site coil of one or more number of large cross sectional area.
• Current Transformer is connected in series with the (phase) carrying high current.

#### 2.What is current transformer function or how does a current transformer work?

• Current transformer often used in power system, Current is very high range in the whole power system so how can you measure it?
• Any meter can not measure high range current in the phase so that time we need current transformer.
• There is current transformer decrease current value mean step down current value and you can get secondary site 0-5 ampere.
• Secondary site of current transformer is always connected with ammeter.
• At the time you think about one doubt in your mind ,primary site is taken high current and current transformer is given range between 0-5A ,So how shown right value of current in the system.
• Answer that we will use instrument of digital ammeter which inbuilt program ,secondary site 0-5 ampere convert to its original value which flow in the system and shown on the meter display.
• You can see follow figure.

#### 3.How many Current Transformer connected with Three Phase System ?

In the three phase system , each phase R , Y , B connected with separately three CT (current transformer ) and average value shown of current in the digital ammeter.

#### 4.Current Transformer is connected in Series or parallel ?

• Current Transformer oftanaly connected in series with phase.
• You know very well ,current can be measured in series( with phase) and voltage can be measured across the two phase (Line).

#### 5.Current Transformer is connected low tension site or high tension site?

CT connected both site low tension (LT) and high tension (HT) site but PT always connected high voltage site because any meter can measure upto 440 voltage.

#### 6.How many types of current transformer ?

Mainly three types of current transformer based on its construction.

1. Wound Type
2. Bar type
3. Toroidal type

#### 7.What is the working principle of current transformer ?

• These transformers are step up transformer or we can say that current transformer step up the value of voltage from primary to secondary .
• Hence according to transformation ratio the current will reduce from secondary.
• And keep mind current point of view ,these are step down transformers which step down the current from primary to secondary.

#### 8.What is the current transformer ratio?

Now for transformer,

#### 9.Why current transformer secondary is always short circuited ?

• Never open the secondary winding circuit of a current transformer while its primary winding is energized .
• When you kept open secondary winding of current transformer that time it will produce too much huge voltage drop secondary site due to current transformer can be a blast.
• So keep this point in your mind when you will work with energized current transformer ,first step is do De-energised current transformer then go ahead for work

#### 10.What is applications of current transformers ?

Following are the main applications of current transformer ..

• Current transformers are used in a panel board of substation and grid station to measure the bus bar current which is very high.
• Current transformers are widely used in a power measuring circuits. the current coil of wattmeter is connected with the current transformer.
• Current transformer are also used in a powerhouse substation and the power panel in conjunction with the relay  .

This all current transformer interview questions  very important consider to your exam and interview.

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