Transformation ratio, KVA rating.

 Rating of an electrical machine / equipment is defined as the output power available from

the same continuously / intermittently without exceeding allowable limit of temperature

rise.

In case of motor or equipment it is expressed as HP or KW.

But, in relation to transformers, the 'kVA rating' of a transformer gives information that how

much apparent power can flow through a transformer without exceeding a temperature rise

associated with the class of insulation used. Transformer always rated in KVA instead of KW.

Main work of transformer is to transmit the power and not to consume the power.

Transformers deals with active and reactive power.

The size of a transformer is determined by the kVA of the load (load demands active power

and reactive power also).

Temperature rise in transformers is due to two types of losses:

iron loss which depend on the applied voltage, and the copper losses which are dependent

on the current flowing through windings.

Types of transformer, Core construction & different parts of

transformer and their function.

Types of Transformers

Transformers Based on Voltage Levels

1. Step-Up Transformer

2. Step-Down Transformer

3. 1:1 Isolation Transformer

 Transformer Based on the Core Medium Used

1. Air Core Transformer

2. Iron Core Transformer

a. Core Type Transformer

b. Shell Type Transformer

c. Berry Type Transformer

 Transformers Based on Winding Arrangement

1. AutoTransformer

2. Two Winding Transformer

3. Three winding transformer

 Transformers Based on Usage

1. Power Transformer

2. Distribution Transformer

3. Instrumentation Transformer

a. Measurement Transformer

b. Protection Transformers

 Transformers Based on the Place of Use

1. indoor transformers

2. outdoor transformers