Types of Transformers
There are three types of power transformers:
- Step-down transformers
- Step-up transformers
- Isolation transformers
They differ according to the transformation ratio of each type of transformer.
The transformation ratio of a transformer is symbolized by m, and is defined as the number of turns of the secondary winding divided by the number of turns of the primary winding.
The following formula applies: m = N₂ / N₁
- m: is the transformation ratio
- N₁: number of primary turns
- N₂: number of secondary turns
There is also a transformer ratio that determines the ratio between the voltage applied to the primary of the transformer and that induced in the secondary.
Here is the following formula: m = U₂ / U₁
- m: is the transformation ratio
- U₁: voltage applied to the primary
- U₂: voltage applied to the secondary
After various calculations, the relationship between the voltages and the coils in a transformer can be expressed by the following formula: m = N₂ / N₁ = U₂ / U₁
With this ratio defined, the types of transformers can be determined.
If the ratio m:
- Is greater than 1, the transformer is said to be an elevator transformer
- Is equal to 1, the transformer is used for circuit separation
- Is less than 1, the transformer is a step-down transformer
Sometimes the transformer is reversible and the new ratio is calculated in the same way.
Autotransformers will also have the same transformation ratio linked to the number of turns and the voltage. The number of primary turns will be the total number of turns and the secondary will be a part of these turns.
