The two-winding transformer has one primary and one secondary winding per phase. It is by far the most common design and the basis of practically all distribution and power transformers worldwide. Despite its simple basic structure, it allows for very powerful and durable designs. Despite all the special designs available, the two-winding transformer remains the standard product of energy technology – a classic that stays modern through continuous refinement.
How does a two-winding transformer differ from a multi-winding transformer?
While the two-winding transformer has only one primary and one secondary winding per phase, multi-winding transformers (e.g. three-winding transformers) have additional windings, for example for different secondary voltages or auxiliary windings for station service power. Two-winding transformers are simpler to manufacture, more compact, and sufficient for most standard applications.
Key Characteristics at a Glance
- One primary and one secondary winding per phase
- Standard design for distribution and power transformers
- Simple design and maintenance
- Available in all voltage and power classes
- Often combined with a tap changer for voltage regulation
- A classic design suitable for nearly every voltage and power class
- Optimal material use for standard applications
Frequently Asked Questions
When is a three-winding transformer the better choice?
Whenever two different secondary voltages need to be tapped from a single transformer, or two separate grids need to be supplied. Three-winding transformers are also common in combination with generators and station-service power supplies in power plants.
Does a two-winding transformer have higher efficiency?
For a comparable design, two-winding transformers are usually somewhat more efficient than multi-winding transformers, since less material is used and there are fewer internal coupling losses. However, the exact difference depends heavily on the specific design parameters.
When does a special design make sense compared with the standard?
When special requirements exist, such as multiple secondary voltages, a compact installation space, extreme environmental conditions, or special vector groups. In standard applications, the two-winding transformer is hard to beat in terms of efficiency and cost-effectiveness.
How is cost-effectiveness optimized over the service life?
Total cost of ownership analyses account for purchase price, expected losses, maintenance costs, service life, and disposal costs. More efficient units with higher acquisition costs often pay for themselves several times over during their service life – especially under continuous, high-utilization operation.
For your next transformer project – whether standard or special design – we advise you on the optimal design. Contact our engineering experts.